diff --git a/backend/_example/memory_store/accessor/admin.go b/backend/_example/memory_store/accessor/admin.go
index 59a5f0d2..efc4f09d 100644
--- a/backend/_example/memory_store/accessor/admin.go
+++ b/backend/_example/memory_store/accessor/admin.go
@@ -9,6 +9,7 @@ package accessor
 import (
 	log "github.com/go-pkgz/lgr"
 	"github.com/pkg/errors"
+
 	"github.com/umputun/remark/backend/app/store/admin"
 )
 
diff --git a/backend/_example/memory_store/accessor/data.go b/backend/_example/memory_store/accessor/data.go
index 7c045c1e..94705230 100644
--- a/backend/_example/memory_store/accessor/data.go
+++ b/backend/_example/memory_store/accessor/data.go
@@ -14,9 +14,8 @@ import (
 
 	"github.com/pkg/errors"
 
-	"github.com/umputun/remark/backend/app/store/engine"
-
 	"github.com/umputun/remark/backend/app/store"
+	"github.com/umputun/remark/backend/app/store/engine"
 )
 
 const lastLimit = 1000
diff --git a/backend/_example/memory_store/go.sum b/backend/_example/memory_store/go.sum
index 10a9ebac..1c2a3f90 100644
--- a/backend/_example/memory_store/go.sum
+++ b/backend/_example/memory_store/go.sum
@@ -157,6 +157,7 @@ github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZb
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/rakyll/statik v0.1.6/go.mod h1:OEi9wJV/fMUAGx1eNjq75DKDsJVuEv1U0oYdX6GX8Zs=
 github.com/rogpeppe/go-internal v1.3.0/go.mod h1:M8bDsm7K2OlrFYOpmOWEs/qY81heoFRclV5y23lUDJ4=
+github.com/rs/xid v1.2.1 h1:mhH9Nq+C1fY2l1XIpgxIiUOfNpRBYH1kKcr+qfKgjRc=
 github.com/rs/xid v1.2.1/go.mod h1:+uKXf+4Djp6Md1KODXJxgGQPKngRmWyn10oCKFzNHOQ=
 github.com/russross/blackfriday/v2 v2.0.1 h1:lPqVAte+HuHNfhJ/0LC98ESWRz8afy9tM/0RK8m9o+Q=
 github.com/russross/blackfriday/v2 v2.0.1/go.mod h1:+Rmxgy9KzJVeS9/2gXHxylqXiyQDYRxCVz55jmeOWTM=
@@ -220,6 +221,7 @@ golang.org/x/exp v0.0.0-20191002040644-a1355ae1e2c3/go.mod h1:NOZ3BPKG0ec/BKJQgn
 golang.org/x/image v0.0.0-20190227222117-0694c2d4d067/go.mod h1:kZ7UVZpmo3dzQBMxlp+ypCbDeSB+sBbTgSJuh5dn5js=
 golang.org/x/image v0.0.0-20190523035834-f03afa92d3ff/go.mod h1:kZ7UVZpmo3dzQBMxlp+ypCbDeSB+sBbTgSJuh5dn5js=
 golang.org/x/image v0.0.0-20190802002840-cff245a6509b/go.mod h1:FeLwcggjj3mMvU+oOTbSwawSJRM1uh48EjtB4UJZlP0=
+golang.org/x/image v0.0.0-20191009234506-e7c1f5e7dbb8 h1:hVwzHzIUGRjiF7EcUjqNxk3NCfkPxbDKRdnNE1Rpg0U=
 golang.org/x/image v0.0.0-20191009234506-e7c1f5e7dbb8/go.mod h1:FeLwcggjj3mMvU+oOTbSwawSJRM1uh48EjtB4UJZlP0=
 golang.org/x/lint v0.0.0-20181026193005-c67002cb31c3/go.mod h1:UVdnD1Gm6xHRNCYTkRU2/jEulfH38KcIWyp/GAMgvoE=
 golang.org/x/lint v0.0.0-20190227174305-5b3e6a55c961/go.mod h1:wehouNa3lNwaWXcvxsM5YxQ5yQlVC4a0KAMCusXpPoU=
diff --git a/backend/_example/memory_store/server/admin.go b/backend/_example/memory_store/server/admin.go
new file mode 100644
index 00000000..9c1d38be
--- /dev/null
+++ b/backend/_example/memory_store/server/admin.go
@@ -0,0 +1,87 @@
+/*
+ * Copyright 2020 Umputun. All rights reserved.
+ * Use of this source code is governed by a MIT-style
+ * license that can be found in the LICENSE file.
+ */
+
+package server
+
+import (
+	"encoding/json"
+
+	"github.com/go-pkgz/jrpc"
+	"github.com/umputun/remark/backend/app/store/admin"
+)
+
+// get admin key
+func (s *RPC) admKeyHndl(id uint64, _ json.RawMessage) (rr jrpc.Response) {
+	key, err := s.adm.Key()
+	if err != nil {
+		return jrpc.Response{Error: err.Error()}
+	}
+	return jrpc.EncodeResponse(id, key, err)
+}
+
+// get admins list
+func (s *RPC) admAdminsHndl(id uint64, params json.RawMessage) (rr jrpc.Response) {
+	var siteID string
+	if err := json.Unmarshal(params, &siteID); err != nil {
+		return jrpc.Response{Error: err.Error()}
+	}
+
+	admins, err := s.adm.Admins(siteID)
+	if err != nil {
+		return jrpc.Response{Error: err.Error()}
+	}
+	return jrpc.EncodeResponse(id, admins, err)
+}
+
+// get admin email
+func (s *RPC) admEmailHndl(id uint64, params json.RawMessage) (rr jrpc.Response) {
+	var siteID string
+	if err := json.Unmarshal(params, &siteID); err != nil {
+		return jrpc.Response{Error: err.Error()}
+	}
+
+	email, err := s.adm.Email(siteID)
+	if err != nil {
+		return jrpc.Response{Error: err.Error()}
+	}
+	return jrpc.EncodeResponse(id, email, err)
+}
+
+// return site enabled status
+func (s *RPC) admEnabledHndl(id uint64, params json.RawMessage) (rr jrpc.Response) {
+	var siteID string
+	if err := json.Unmarshal(params, &siteID); err != nil {
+		return jrpc.Response{Error: err.Error()}
+	}
+
+	ok, err := s.adm.Enabled(siteID)
+	if err != nil {
+		return jrpc.Response{Error: err.Error()}
+	}
+	return jrpc.EncodeResponse(id, ok, err)
+}
+
+// onEvent returns nothing, callback to OnEvent
+func (s *RPC) admEventHndl(id uint64, params json.RawMessage) (rr jrpc.Response) {
+	var siteID string
+	var ps []interface{}
+	if err := json.Unmarshal(params, &ps); err != nil {
+		return jrpc.Response{Error: err.Error()}
+	}
+	siteID, ok := ps[0].(string)
+	if !ok {
+		return jrpc.Response{Error: "wrong siteID type"}
+	}
+	evType, ok := ps[1].(float64)
+	if !ok {
+		return jrpc.Response{Error: "wrong event type"}
+	}
+	err := s.adm.OnEvent(siteID, admin.EventType(evType))
+	if err != nil {
+		return jrpc.Response{Error: err.Error()}
+	}
+	return jrpc.EncodeResponse(id, nil, err)
+}
diff --git a/backend/_example/memory_store/server/admin_test.go b/backend/_example/memory_store/server/admin_test.go
new file mode 100644
index 00000000..f91b3998
--- /dev/null
+++ b/backend/_example/memory_store/server/admin_test.go
@@ -0,0 +1,88 @@
+/*
+ * Copyright 2020 Umputun. All rights reserved.
+ * Use of this source code is governed by a MIT-style
+ * license that can be found in the LICENSE file.
+ */
+
+package server
+
+import (
+	"fmt"
+	"net/http"
+	"testing"
+	"time"
+
+	"github.com/go-pkgz/jrpc"
+	"github.com/stretchr/testify/assert"
+	"github.com/umputun/remark/backend/app/store/admin"
+)
+
+func TestRPC_admKeyHndl(t *testing.T) {
+	_, port, teardown := prepTestStore(t)
+	defer teardown()
+	api := fmt.Sprintf("http://localhost:%d/test", port)
+
+	ra := admin.RPC{Client: jrpc.Client{API: api, Client: http.Client{Timeout: 1 * time.Second}}}
+	key, err := ra.Key()
+	assert.NoError(t, err)
+	assert.Equal(t, "secret", key)
+}
+
+func TestRPC_admAdminsHndl(t *testing.T) {
+	_, port, teardown := prepTestStore(t)
+	defer teardown()
+	api := fmt.Sprintf("http://localhost:%d/test", port)
+
+	ra := admin.RPC{Client: jrpc.Client{API: api, Client: http.Client{Timeout: 1 * time.Second}}}
+	_, err := ra.Admins("bad site")
+	assert.EqualError(t, err, "site bad site not found")
+
+	admins, err := ra.Admins("test-site")
+	assert.NoError(t, err)
+	assert.Equal(t, []string{"id1", "id2"}, admins)
+}
+
+func TestRPC_admEmailHndl(t *testing.T) {
+	_, port, teardown := prepTestStore(t)
+	defer teardown()
+	api := fmt.Sprintf("http://localhost:%d/test", port)
+
+	ra := admin.RPC{Client: jrpc.Client{API: api, Client: http.Client{Timeout: 1 * time.Second}}}
+	_, err := ra.Admins("bad site")
+	assert.EqualError(t, err, "site bad site not found")
+
+	email, err := ra.Email("test-site")
+	assert.NoError(t, err)
+	assert.Equal(t, "admin@example.com", email)
+}
+
+func TestRPC_admEnabledHndl(t *testing.T) {
+	_, port, teardown := prepTestStore(t)
+	defer teardown()
+	api := fmt.Sprintf("http://localhost:%d/test", port)
+
+	ra := admin.RPC{Client: jrpc.Client{API: api, Client: http.Client{Timeout: 1 * time.Second}}}
+	_, err := ra.Enabled("bad site")
+	assert.EqualError(t, err, "site bad site not found")
+
+	ok, err := ra.Enabled("test-site")
+	assert.NoError(t, err)
+	assert.Equal(t, true, ok)
+
+	ok, err = ra.Enabled("test-site-disabled")
+	assert.NoError(t, err)
+	assert.Equal(t, false, ok)
+}
+
+func TestRPC_admEventHndl(t *testing.T) {
+	_, port, teardown := prepTestStore(t)
+	defer teardown()
+	api := fmt.Sprintf("http://localhost:%d/test", port)
+
+	ra := admin.RPC{Client: jrpc.Client{API: api, Client: http.Client{Timeout: 1 * time.Second}}}
+	err := ra.OnEvent("bad site", admin.EvCreate)
+	assert.EqualError(t, err, "site bad site not found")
+
+	err = ra.OnEvent("test-site", admin.EvCreate)
+	assert.NoError(t, err)
+}
diff --git a/backend/_example/memory_store/server/data.go b/backend/_example/memory_store/server/data.go
new file mode 100644
index 00000000..9b6a9424
--- /dev/null
+++ b/backend/_example/memory_store/server/data.go
@@ -0,0 +1,124 @@
+/*
+ * Copyright 2020 Umputun. All rights reserved.
+ * Use of this source code is governed by a MIT-style
+ * license that can be found in the LICENSE file.
+ */
+
+package server
+
+import (
+	"encoding/json"
+
+	"github.com/go-pkgz/jrpc"
+	"github.com/umputun/remark/backend/app/store"
+	"github.com/umputun/remark/backend/app/store/engine"
+)
+
+func (s *RPC) createHndl(id uint64, params json.RawMessage) (rr jrpc.Response) {
+	comment := store.Comment{}
+	if err := json.Unmarshal(params, &comment); err != nil {
+		return jrpc.Response{Error: err.Error()}
+	}
+	commentID, err := s.eng.Create(comment)
+	return jrpc.EncodeResponse(id, commentID, err)
+}
+
+// Find comments
+func (s *RPC) findHndl(id uint64, params json.RawMessage) (rr jrpc.Response) {
+	req := engine.FindRequest{}
+	if err := json.Unmarshal(params, &req); err != nil {
+		return jrpc.Response{Error: err.Error()}
+	}
+	resp, err := s.eng.Find(req)
+	return jrpc.EncodeResponse(id, resp, err)
+}
+
+// Get comment
+func (s *RPC) getHndl(id uint64, params json.RawMessage) (rr jrpc.Response) {
+	req := engine.GetRequest{}
+	if err := json.Unmarshal(params, &req); err != nil {
+		return jrpc.Response{Error: err.Error()}
+	}
+	comment, err := s.eng.Get(req)
+	return jrpc.EncodeResponse(id, comment, err)
+}
+
+// Update comment
+func (s *RPC) updateHndl(id uint64, params json.RawMessage) (rr jrpc.Response) {
+	comment := store.Comment{}
+	if err := json.Unmarshal(params, &comment); err != nil {
+		return jrpc.Response{Error: err.Error()}
+	}
+	err := s.eng.Update(comment)
+	return jrpc.EncodeResponse(id, nil, err)
+}
+
+// counts for site and users
+func (s *RPC) countHndl(id uint64, params json.RawMessage) (rr jrpc.Response) {
+	req := engine.FindRequest{}
+	if err := json.Unmarshal(params, &req); err != nil {
+		return jrpc.Response{Error: err.Error()}
+	}
+	count, err := s.eng.Count(req)
+	return jrpc.EncodeResponse(id, count, err)
+}
+
+// info get post meta info
+func (s *RPC) infoHndl(id uint64, params json.RawMessage) (rr jrpc.Response) {
+	req := engine.InfoRequest{}
+	if err := json.Unmarshal(params, &req); err != nil {
+		return jrpc.Response{Error: err.Error()}
+	}
+	info, err := s.eng.Info(req)
+	return jrpc.EncodeResponse(id, info, err)
+}
+
+// flagHndl get and sets flag value
+func (s *RPC) flagHndl(id uint64, params json.RawMessage) (rr jrpc.Response) {
+	req := engine.FlagRequest{}
+	if err := json.Unmarshal(params, &req); err != nil {
+		return jrpc.Response{Error: err.Error()}
+	}
+	status, err := s.eng.Flag(req)
+	return jrpc.EncodeResponse(id, status, err)
+}
+
+// listFlagsHndl list flags for given request
+func (s *RPC) listFlagsHndl(id uint64, params json.RawMessage) (rr jrpc.Response) {
+	req := engine.FlagRequest{}
+	if err := json.Unmarshal(params, &req); err != nil {
+		return jrpc.Response{Error: err.Error()}
+	}
+	flags, err := s.eng.ListFlags(req)
+	return jrpc.EncodeResponse(id, flags, err)
+}
+
+// userDetailHndl sets or gets single detail value, or gets all details for requested site.
+// userDetailHndl returns list even for single entry request is a compromise in order to have both single detail getting and setting
+// and all site's details listing under the same function (and not to extend engine interface by two separate functions).
+func (s *RPC) userDetailHndl(id uint64, params json.RawMessage) (rr jrpc.Response) {
+	req := engine.UserDetailRequest{}
+	if err := json.Unmarshal(params, &req); err != nil {
+		return jrpc.Response{Error: err.Error()}
+	}
+	value, err := s.eng.UserDetail(req)
+	return jrpc.EncodeResponse(id, value, err)
+}
+
+// deleteHndl delete post(s), user, comment, user details, or everything
+func (s *RPC) deleteHndl(id uint64, params json.RawMessage) (rr jrpc.Response) {
+	req := engine.DeleteRequest{}
+	if err := json.Unmarshal(params, &req); err != nil {
+		return jrpc.Response{Error: err.Error()}
+	}
+	err := s.eng.Delete(req)
+	return jrpc.EncodeResponse(id, nil, err)
+}
+
+// close store
+func (s *RPC) closeHndl(_ uint64, _ json.RawMessage) (rr jrpc.Response) {
+	if err := s.eng.Close(); err != nil {
+		return jrpc.Response{Error: err.Error()}
+	}
+	return jrpc.Response{}
+}
diff --git a/backend/_example/memory_store/server/data_test.go b/backend/_example/memory_store/server/data_test.go
new file mode 100644
index 00000000..938e73c0
--- /dev/null
+++ b/backend/_example/memory_store/server/data_test.go
@@ -0,0 +1,305 @@
+/*
+ * Copyright 2020 Umputun. All rights reserved.
+ * Use of this source code is governed by a MIT-style
+ * license that can be found in the LICENSE file.
+ */
+
+package server
+
+import (
+	"fmt"
+	"net/http"
+	"testing"
+	"time"
+
+	"github.com/go-pkgz/jrpc"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+	"github.com/umputun/remark/backend/app/store"
+	"github.com/umputun/remark/backend/app/store/engine"
+)
+
+func TestRPC_createHndl(t *testing.T) {
+	_, port, teardown := prepTestStore(t)
+	defer teardown()
+	api := fmt.Sprintf("http://localhost:%d/test", port)
+
+	re := engine.RPC{Client: jrpc.Client{API: api, Client: http.Client{Timeout: 1 * time.Second}}}
+	id, err := re.Create(store.Comment{ID: "123456", Locator: store.Locator{SiteID: "test-site", URL: "http://example.com/post1"},
+		Text: "text 123", User: store.User{ID: "u1", Name: "user1"}})
+	assert.NoError(t, err)
+	assert.Equal(t, "123456", id)
+}
+
+func TestRPC_findHndl(t *testing.T) {
+	_, port, teardown := prepTestStore(t)
+	defer teardown()
+	api := fmt.Sprintf("http://localhost:%d/test", port)
+
+	re := engine.RPC{Client: jrpc.Client{API: api, Client: http.Client{Timeout: 1 * time.Second}}}
+	findReq := engine.FindRequest{Locator: store.Locator{SiteID: "test-site", URL: "http://example.com/post1"}}
+	comments, err := re.Find(findReq)
+	require.NoError(t, err)
+	assert.Equal(t, 0, len(comments))
+
+	c := store.Comment{ID: "123456", Locator: store.Locator{SiteID: "test-site", URL: "http://example.com/post1"},
+		Text: "text 123", User: store.User{ID: "u1", Name: "user1"}}
+	id, err := re.Create(c)
+	assert.NoError(t, err)
+	assert.Equal(t, "123456", id)
+
+	comments, err = re.Find(findReq)
+	require.NoError(t, err)
+	assert.Equal(t, 1, len(comments))
+	assert.Equal(t, c, comments[0])
+}
+
+func TestRPC_getHndl(t *testing.T) {
+	_, port, teardown := prepTestStore(t)
+	defer teardown()
+	api := fmt.Sprintf("http://localhost:%d/test", port)
+
+	re := engine.RPC{Client: jrpc.Client{API: api, Client: http.Client{Timeout: 1 * time.Second}}}
+	req := engine.GetRequest{
+		Locator:   store.Locator{SiteID: "test-site", URL: "http://example.com/post1"},
+		CommentID: "123456",
+	}
+
+	_, err := re.Get(req)
+	assert.EqualError(t, err, "not found")
+
+	c := store.Comment{ID: "123456", Locator: store.Locator{SiteID: "test-site", URL: "http://example.com/post1"},
+		Text: "text 123", User: store.User{ID: "u1", Name: "user1"}}
+	_, err = re.Create(c)
+	assert.NoError(t, err)
+
+	comment, err := re.Get(req)
+	assert.NoError(t, err)
+	assert.Equal(t, c, comment)
+}
+
+func TestRPC_updateHndl(t *testing.T) {
+	_, port, teardown := prepTestStore(t)
+	defer teardown()
+	api := fmt.Sprintf("http://localhost:%d/test", port)
+
+	re := engine.RPC{Client: jrpc.Client{API: api, Client: http.Client{Timeout: 1 * time.Second}}}
+
+	c := store.Comment{ID: "123456", Locator: store.Locator{SiteID: "test-site", URL: "http://example.com/post1"},
+		Text: "text 123", User: store.User{ID: "u1", Name: "user1"}}
+	err := re.Update(c)
+	assert.EqualError(t, err, "not found")
+
+	_, err = re.Create(c)
+	assert.NoError(t, err)
+
+	c.Text = "updates"
+	err = re.Update(c)
+	assert.NoError(t, err)
+
+	req := engine.GetRequest{
+		Locator:   store.Locator{SiteID: "test-site", URL: "http://example.com/post1"},
+		CommentID: "123456",
+	}
+	comment, err := re.Get(req)
+	assert.NoError(t, err)
+	assert.Equal(t, c, comment)
+}
+
+func TestRPC_countHndl(t *testing.T) {
+	_, port, teardown := prepTestStore(t)
+	defer teardown()
+	api := fmt.Sprintf("http://localhost:%d/test", port)
+
+	re := engine.RPC{Client: jrpc.Client{API: api, Client: http.Client{Timeout: 1 * time.Second}}}
+	findReq := engine.FindRequest{Locator: store.Locator{SiteID: "test-site", URL: "http://example.com/post1"}}
+	count, err := re.Count(findReq)
+	require.NoError(t, err)
+	assert.Equal(t, 0, count)
+
+	c := store.Comment{ID: "123456", Locator: store.Locator{SiteID: "test-site", URL: "http://example.com/post1"},
+		Text: "text 123", User: store.User{ID: "u1", Name: "user1"}}
+	id, err := re.Create(c)
+	assert.NoError(t, err)
+	assert.Equal(t, "123456", id)
+
+	count, err = re.Count(findReq)
+	require.NoError(t, err)
+	assert.Equal(t, 1, count)
+}
+
+func TestRPC_infoHndl(t *testing.T) {
+	_, port, teardown := prepTestStore(t)
+	defer teardown()
+	api := fmt.Sprintf("http://localhost:%d/test", port)
+
+	re := engine.RPC{Client: jrpc.Client{API: api, Client: http.Client{Timeout: 1 * time.Second}}}
+
+	c := store.Comment{ID: "123456", Locator: store.Locator{SiteID: "test-site", URL: "http://example.com/post1"},
+		Text: "text 123", User: store.User{ID: "u1", Name: "user1"}}
+	id, err := re.Create(c)
+	assert.NoError(t, err)
+	assert.Equal(t, "123456", id)
+
+	infoReq := engine.InfoRequest{Locator: store.Locator{SiteID: "test-site", URL: "http://example.com/post1"}}
+	info, err := re.Info(infoReq)
+	require.NoError(t, err)
+	assert.Equal(t, 1, len(info))
+	i := info[0]
+	assert.Equal(t, store.PostInfo{URL: "http://example.com/post1", Count: 1}, i)
+}
+
+func TestRPC_flagHndl(t *testing.T) {
+	_, port, teardown := prepTestStore(t)
+	defer teardown()
+	api := fmt.Sprintf("http://localhost:%d/test", port)
+
+	re := engine.RPC{Client: jrpc.Client{API: api, Client: http.Client{Timeout: 1 * time.Second}}}
+
+	c := store.Comment{ID: "123456", Locator: store.Locator{SiteID: "test-site", URL: "http://example.com/post1"},
+		Text: "text 123", User: store.User{ID: "u1", Name: "user1"}}
+	id, err := re.Create(c)
+	assert.NoError(t, err)
+	assert.Equal(t, "123456", id)
+
+	flagReq := engine.FlagRequest{
+		Flag: engine.Verified,
+		Locator: store.Locator{
+			SiteID: "test-site",
+		},
+		UserID: "u1",
+	}
+	status, err := re.Flag(flagReq)
+	require.NoError(t, err)
+	assert.Equal(t, false, status)
+
+	flagReq.Update = engine.FlagTrue
+	status, err = re.Flag(flagReq)
+	require.NoError(t, err)
+	assert.Equal(t, true, status)
+
+	flagReq.Update = engine.FlagNonSet
+	status, err = re.Flag(flagReq)
+	require.NoError(t, err)
+	assert.Equal(t, true, status)
+}
+
+func TestRPC_listFlagsHndl(t *testing.T) {
+	_, port, teardown := prepTestStore(t)
+	defer teardown()
+	api := fmt.Sprintf("http://localhost:%d/test", port)
+
+	re := engine.RPC{Client: jrpc.Client{API: api, Client: http.Client{Timeout: 1 * time.Second}}}
+
+	c := store.Comment{ID: "123456", Locator: store.Locator{SiteID: "test-site", URL: "http://example.com/post1"},
+		Text: "text 123", User: store.User{ID: "u1", Name: "user1"}}
+	id, err := re.Create(c)
+	assert.NoError(t, err)
+	assert.Equal(t, "123456", id)
+
+	flagReq := engine.FlagRequest{
+		Flag:   engine.Verified,
+		UserID: "u1",
+		Locator: store.Locator{
+			SiteID: "test-site",
+		},
+	}
+	flags, err := re.ListFlags(flagReq)
+	require.NoError(t, err)
+	assert.Equal(t, []interface{}{}, flags)
+
+	flagReq.Update = engine.FlagTrue
+	status, err := re.Flag(flagReq)
+	require.NoError(t, err)
+	assert.Equal(t, true, status)
+
+	flags, err = re.ListFlags(flagReq)
+	require.NoError(t, err)
+	assert.Equal(t, []interface{}{"u1"}, flags)
+}
+
+func TestRPC_userDetailHndl(t *testing.T) {
+	_, port, teardown := prepTestStore(t)
+	defer teardown()
+	api := fmt.Sprintf("http://localhost:%d/test", port)
+
+	re := engine.RPC{Client: jrpc.Client{API: api, Client: http.Client{Timeout: 1 * time.Second}}}
+
+	// add to entries to DB before we start
+	result, err := re.UserDetail(engine.UserDetailRequest{Locator: store.Locator{SiteID: "test-site"}, UserID: "u1", Detail: engine.UserEmail, Update: "test@example.com"})
+	assert.NoError(t, err, "No error inserting entry expected")
+	assert.ElementsMatch(t, []engine.UserDetailEntry{{UserID: "u1", Email: "test@example.com"}}, result)
+	result, err = re.UserDetail(engine.UserDetailRequest{Locator: store.Locator{SiteID: "test-site"}, UserID: "u2", Detail: engine.UserEmail, Update: "other@example.com"})
+	assert.NoError(t, err, "No error inserting entry expected")
+	assert.ElementsMatch(t, []engine.UserDetailEntry{{UserID: "u2", Email: "other@example.com"}}, result)
+
+	// try to change existing entry with wrong SiteID
+	result, err = re.UserDetail(engine.UserDetailRequest{Locator: store.Locator{SiteID: "bad"}, UserID: "u2", Detail: engine.UserEmail, Update: "not_relevant"})
+	assert.NoError(t, err, "Updating existing entry with wrong SiteID doesn't produce error")
+	assert.ElementsMatch(t, []engine.UserDetailEntry{}, result, "Updating existing entry with wrong SiteID doesn't change anything")
+
+	// stateless tests without changing the state we set up before
+	var testData = []struct {
+		req      engine.UserDetailRequest
+		error    string
+		expected []engine.UserDetailEntry
+	}{
+		{req: engine.UserDetailRequest{Locator: store.Locator{SiteID: "test-site"}, UserID: "u1", Detail: engine.UserEmail},
+			expected: []engine.UserDetailEntry{{UserID: "u1", Email: "test@example.com"}}},
+		{req: engine.UserDetailRequest{Locator: store.Locator{SiteID: "bad"}, UserID: "u1", Detail: engine.UserEmail},
+			expected: []engine.UserDetailEntry{}},
+		{req: engine.UserDetailRequest{Locator: store.Locator{SiteID: "test-site"}, UserID: "u1xyz", Detail: engine.UserEmail},
+			expected: []engine.UserDetailEntry{}},
+		{req: engine.UserDetailRequest{Detail: engine.UserEmail, Update: "new_value"},
+			error: `userid cannot be empty in request for single detail`},
+		{req: engine.UserDetailRequest{Detail: engine.UserDetail("bad")},
+			error: `unsupported detail "bad"`},
+		{req: engine.UserDetailRequest{Update: "not_relevant", Detail: engine.AllUserDetails},
+			error: `unsupported request with userdetail all`},
+		{req: engine.UserDetailRequest{Locator: store.Locator{SiteID: "test-site"}, Detail: engine.AllUserDetails},
+			expected: []engine.UserDetailEntry{{UserID: "u1", Email: "test@example.com"}, {UserID: "u2", Email: "other@example.com"}}},
+	}
+
+	for i, x := range testData {
+		result, err := re.UserDetail(x.req)
+		if x.error != "" {
+			assert.EqualError(t, err, x.error, "Error should match expected for case %d", i)
+		} else {
+			assert.NoError(t, err, "Error is not expected expected for case %d", i)
+		}
+		assert.ElementsMatch(t, x.expected, result, "Result should match expected for case %d", i)
+	}
+}
+
+func TestRPC_deleteHndl(t *testing.T) {
+	_, port, teardown := prepTestStore(t)
+	defer teardown()
+	api := fmt.Sprintf("http://localhost:%d/test", port)
+
+	re := engine.RPC{Client: jrpc.Client{API: api, Client: http.Client{Timeout: 1 * time.Second}}}
+	req := engine.DeleteRequest{
+		Locator:   store.Locator{SiteID: "test-site", URL: "http://example.com/post1"},
+		CommentID: "123456",
+	}
+
+	err := re.Delete(req)
+	assert.EqualError(t, err, "not found")
+
+	c := store.Comment{ID: "123456", Locator: store.Locator{SiteID: "test-site", URL: "http://example.com/post1"},
+		Text: "text 123", User: store.User{ID: "u1", Name: "user1"}}
+	_, err = re.Create(c)
+	assert.NoError(t, err)
+
+	err = re.Delete(req)
+	assert.NoError(t, err)
+}
+
+func TestRPC_closeHndl(t *testing.T) {
+	_, port, teardown := prepTestStore(t)
+	defer teardown()
+	api := fmt.Sprintf("http://localhost:%d/test", port)
+
+	re := engine.RPC{Client: jrpc.Client{API: api, Client: http.Client{Timeout: 1 * time.Second}}}
+	err := re.Close()
+	assert.NoError(t, err)
+}
diff --git a/backend/_example/memory_store/server/rpc.go b/backend/_example/memory_store/server/rpc.go
index e5b1414d..b5ce3290 100644
--- a/backend/_example/memory_store/server/rpc.go
+++ b/backend/_example/memory_store/server/rpc.go
@@ -1,11 +1,14 @@
+/*
+ * Copyright 2020 Umputun. All rights reserved.
+ * Use of this source code is governed by a MIT-style
+ * license that can be found in the LICENSE file.
+ */
+
 package server
 
 import (
-	"encoding/json"
-
 	"github.com/go-pkgz/jrpc"
 
-	"github.com/umputun/remark/backend/app/store"
 	"github.com/umputun/remark/backend/app/store/admin"
 	"github.com/umputun/remark/backend/app/store/engine"
 )
@@ -50,185 +53,3 @@ func (s *RPC) addHandlers() {
 		"event":   s.admEventHndl,
 	})
 }
-
-func (s *RPC) createHndl(id uint64, params json.RawMessage) (rr jrpc.Response) {
-	comment := store.Comment{}
-	if err := json.Unmarshal(params, &comment); err != nil {
-		return jrpc.Response{Error: err.Error()}
-	}
-	commentID, err := s.eng.Create(comment)
-	return jrpc.EncodeResponse(id, commentID, err)
-}
-
-// Find comments
-func (s *RPC) findHndl(id uint64, params json.RawMessage) (rr jrpc.Response) {
-	req := engine.FindRequest{}
-	if err := json.Unmarshal(params, &req); err != nil {
-		return jrpc.Response{Error: err.Error()}
-	}
-	resp, err := s.eng.Find(req)
-	return jrpc.EncodeResponse(id, resp, err)
-}
-
-// Get comment
-func (s *RPC) getHndl(id uint64, params json.RawMessage) (rr jrpc.Response) {
-	req := engine.GetRequest{}
-	if err := json.Unmarshal(params, &req); err != nil {
-		return jrpc.Response{Error: err.Error()}
-	}
-	comment, err := s.eng.Get(req)
-	return jrpc.EncodeResponse(id, comment, err)
-}
-
-// Update comment
-func (s *RPC) updateHndl(id uint64, params json.RawMessage) (rr jrpc.Response) {
-	comment := store.Comment{}
-	if err := json.Unmarshal(params, &comment); err != nil {
-		return jrpc.Response{Error: err.Error()}
-	}
-	err := s.eng.Update(comment)
-	return jrpc.EncodeResponse(id, nil, err)
-}
-
-// counts for site and users
-func (s *RPC) countHndl(id uint64, params json.RawMessage) (rr jrpc.Response) {
-	req := engine.FindRequest{}
-	if err := json.Unmarshal(params, &req); err != nil {
-		return jrpc.Response{Error: err.Error()}
-	}
-	count, err := s.eng.Count(req)
-	return jrpc.EncodeResponse(id, count, err)
-}
-
-// info get post meta info
-func (s *RPC) infoHndl(id uint64, params json.RawMessage) (rr jrpc.Response) {
-	req := engine.InfoRequest{}
-	if err := json.Unmarshal(params, &req); err != nil {
-		return jrpc.Response{Error: err.Error()}
-	}
-	info, err := s.eng.Info(req)
-	return jrpc.EncodeResponse(id, info, err)
-}
-
-// flagHndl get and sets flag value
-func (s *RPC) flagHndl(id uint64, params json.RawMessage) (rr jrpc.Response) {
-	req := engine.FlagRequest{}
-	if err := json.Unmarshal(params, &req); err != nil {
-		return jrpc.Response{Error: err.Error()}
-	}
-	status, err := s.eng.Flag(req)
-	return jrpc.EncodeResponse(id, status, err)
-}
-
-// listFlagsHndl list flags for given request
-func (s *RPC) listFlagsHndl(id uint64, params json.RawMessage) (rr jrpc.Response) {
-	req := engine.FlagRequest{}
-	if err := json.Unmarshal(params, &req); err != nil {
-		return jrpc.Response{Error: err.Error()}
-	}
-	flags, err := s.eng.ListFlags(req)
-	return jrpc.EncodeResponse(id, flags, err)
-}
-
-// userDetailHndl sets or gets single detail value, or gets all details for requested site.
-// userDetailHndl returns list even for single entry request is a compromise in order to have both single detail getting and setting
-// and all site's details listing under the same function (and not to extend engine interface by two separate functions).
-func (s *RPC) userDetailHndl(id uint64, params json.RawMessage) (rr jrpc.Response) {
-	req := engine.UserDetailRequest{}
-	if err := json.Unmarshal(params, &req); err != nil {
-		return jrpc.Response{Error: err.Error()}
-	}
-	value, err := s.eng.UserDetail(req)
-	return jrpc.EncodeResponse(id, value, err)
-}
-
-// deleteHndl delete post(s), user, comment, user details, or everything
-func (s *RPC) deleteHndl(id uint64, params json.RawMessage) (rr jrpc.Response) {
-	req := engine.DeleteRequest{}
-	if err := json.Unmarshal(params, &req); err != nil {
-		return jrpc.Response{Error: err.Error()}
-	}
-	err := s.eng.Delete(req)
-	return jrpc.EncodeResponse(id, nil, err)
-}
-
-// close store
-func (s *RPC) closeHndl(id uint64, _ json.RawMessage) (rr jrpc.Response) {
-	if err := s.eng.Close(); err != nil {
-		return jrpc.Response{Error: err.Error()}
-	}
-	return jrpc.Response{}
-}
-
-// get admin key
-func (s *RPC) admKeyHndl(id uint64, _ json.RawMessage) (rr jrpc.Response) {
-	key, err := s.adm.Key()
-	if err != nil {
-		return jrpc.Response{Error: err.Error()}
-	}
-	return jrpc.EncodeResponse(id, key, err)
-}
-
-// get admins list
-func (s *RPC) admAdminsHndl(id uint64, params json.RawMessage) (rr jrpc.Response) {
-	var siteID string
-	if err := json.Unmarshal(params, &siteID); err != nil {
-		return jrpc.Response{Error: err.Error()}
-	}
-
-	admins, err := s.adm.Admins(siteID)
-	if err != nil {
-		return jrpc.Response{Error: err.Error()}
-	}
-	return jrpc.EncodeResponse(id, admins, err)
-}
-
-// get admin email
-func (s *RPC) admEmailHndl(id uint64, params json.RawMessage) (rr jrpc.Response) {
-	var siteID string
-	if err := json.Unmarshal(params, &siteID); err != nil {
-		return jrpc.Response{Error: err.Error()}
-	}
-
-	email, err := s.adm.Email(siteID)
-	if err != nil {
-		return jrpc.Response{Error: err.Error()}
-	}
-	return jrpc.EncodeResponse(id, email, err)
-}
-
-// return site enabled status
-func (s *RPC) admEnabledHndl(id uint64, params json.RawMessage) (rr jrpc.Response) {
-	var siteID string
-	if err := json.Unmarshal(params, &siteID); err != nil {
-		return jrpc.Response{Error: err.Error()}
-	}
-
-	ok, err := s.adm.Enabled(siteID)
-	if err != nil {
-		return jrpc.Response{Error: err.Error()}
-	}
-	return jrpc.EncodeResponse(id, ok, err)
-}
-
-// onEvent returns nothing, callback to OnEvent
-func (s *RPC) admEventHndl(id uint64, params json.RawMessage) (rr jrpc.Response) {
-	var siteID string
-	ps := []interface{}{}
-	if err := json.Unmarshal(params, &ps); err != nil {
-		return jrpc.Response{Error: err.Error()}
-	}
-	siteID, ok := ps[0].(string)
-	if !ok {
-		return jrpc.Response{Error: "wrong siteID type"}
-	}
-	evType, ok := ps[1].(float64)
-	if !ok {
-		return jrpc.Response{Error: "wrong event type"}
-	}
-	err := s.adm.OnEvent(siteID, admin.EventType(evType))
-	if err != nil {
-		return jrpc.Response{Error: err.Error()}
-	}
-	return jrpc.EncodeResponse(id, nil, err)
-}
diff --git a/backend/_example/memory_store/server/rpc_test.go b/backend/_example/memory_store/server/rpc_test.go
index 5142cf8c..d9d395ef 100644
--- a/backend/_example/memory_store/server/rpc_test.go
+++ b/backend/_example/memory_store/server/rpc_test.go
@@ -1,5 +1,5 @@
 /*
- * Copyright 2019 Umputun. All rights reserved.
+ * Copyright 2020 Umputun. All rights reserved.
  * Use of this source code is governed by a MIT-style
  * license that can be found in the LICENSE file.
  */
@@ -16,369 +16,11 @@ import (
 
 	"github.com/go-pkgz/jrpc"
 	log "github.com/go-pkgz/lgr"
-	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
-	"github.com/umputun/remark/backend/app/store"
-	"github.com/umputun/remark/backend/app/store/admin"
-	"github.com/umputun/remark/backend/app/store/engine"
 
 	"github.com/umputun/remark/memory_store/accessor"
 )
 
-func TestRPC_createHndl(t *testing.T) {
-	_, port, teardown := prepTestStore(t)
-	defer teardown()
-	api := fmt.Sprintf("http://localhost:%d/test", port)
-
-	re := engine.RPC{Client: jrpc.Client{API: api, Client: http.Client{Timeout: 1 * time.Second}}}
-	id, err := re.Create(store.Comment{ID: "123456", Locator: store.Locator{SiteID: "test-site", URL: "http://example.com/post1"},
-		Text: "text 123", User: store.User{ID: "u1", Name: "user1"}})
-	assert.NoError(t, err)
-	assert.Equal(t, "123456", id)
-}
-
-func TestRPC_findHndl(t *testing.T) {
-	_, port, teardown := prepTestStore(t)
-	defer teardown()
-	api := fmt.Sprintf("http://localhost:%d/test", port)
-
-	re := engine.RPC{Client: jrpc.Client{API: api, Client: http.Client{Timeout: 1 * time.Second}}}
-	findReq := engine.FindRequest{Locator: store.Locator{SiteID: "test-site", URL: "http://example.com/post1"}}
-	comments, err := re.Find(findReq)
-	require.NoError(t, err)
-	assert.Equal(t, 0, len(comments))
-
-	c := store.Comment{ID: "123456", Locator: store.Locator{SiteID: "test-site", URL: "http://example.com/post1"},
-		Text: "text 123", User: store.User{ID: "u1", Name: "user1"}}
-	id, err := re.Create(c)
-	assert.NoError(t, err)
-	assert.Equal(t, "123456", id)
-
-	comments, err = re.Find(findReq)
-	require.NoError(t, err)
-	assert.Equal(t, 1, len(comments))
-	assert.Equal(t, c, comments[0])
-}
-
-func TestRPC_getHndl(t *testing.T) {
-	_, port, teardown := prepTestStore(t)
-	defer teardown()
-	api := fmt.Sprintf("http://localhost:%d/test", port)
-
-	re := engine.RPC{Client: jrpc.Client{API: api, Client: http.Client{Timeout: 1 * time.Second}}}
-	req := engine.GetRequest{
-		Locator:   store.Locator{SiteID: "test-site", URL: "http://example.com/post1"},
-		CommentID: "123456",
-	}
-
-	_, err := re.Get(req)
-	assert.EqualError(t, err, "not found")
-
-	c := store.Comment{ID: "123456", Locator: store.Locator{SiteID: "test-site", URL: "http://example.com/post1"},
-		Text: "text 123", User: store.User{ID: "u1", Name: "user1"}}
-	_, err = re.Create(c)
-	assert.NoError(t, err)
-
-	comment, err := re.Get(req)
-	assert.NoError(t, err)
-	assert.Equal(t, c, comment)
-}
-
-func TestRPC_updateHndl(t *testing.T) {
-	_, port, teardown := prepTestStore(t)
-	defer teardown()
-	api := fmt.Sprintf("http://localhost:%d/test", port)
-
-	re := engine.RPC{Client: jrpc.Client{API: api, Client: http.Client{Timeout: 1 * time.Second}}}
-
-	c := store.Comment{ID: "123456", Locator: store.Locator{SiteID: "test-site", URL: "http://example.com/post1"},
-		Text: "text 123", User: store.User{ID: "u1", Name: "user1"}}
-	err := re.Update(c)
-	assert.EqualError(t, err, "not found")
-
-	_, err = re.Create(c)
-	assert.NoError(t, err)
-
-	c.Text = "updates"
-	err = re.Update(c)
-	assert.NoError(t, err)
-
-	req := engine.GetRequest{
-		Locator:   store.Locator{SiteID: "test-site", URL: "http://example.com/post1"},
-		CommentID: "123456",
-	}
-	comment, err := re.Get(req)
-	assert.NoError(t, err)
-	assert.Equal(t, c, comment)
-}
-
-func TestRPC_countHndl(t *testing.T) {
-	_, port, teardown := prepTestStore(t)
-	defer teardown()
-	api := fmt.Sprintf("http://localhost:%d/test", port)
-
-	re := engine.RPC{Client: jrpc.Client{API: api, Client: http.Client{Timeout: 1 * time.Second}}}
-	findReq := engine.FindRequest{Locator: store.Locator{SiteID: "test-site", URL: "http://example.com/post1"}}
-	count, err := re.Count(findReq)
-	require.NoError(t, err)
-	assert.Equal(t, 0, count)
-
-	c := store.Comment{ID: "123456", Locator: store.Locator{SiteID: "test-site", URL: "http://example.com/post1"},
-		Text: "text 123", User: store.User{ID: "u1", Name: "user1"}}
-	id, err := re.Create(c)
-	assert.NoError(t, err)
-	assert.Equal(t, "123456", id)
-
-	count, err = re.Count(findReq)
-	require.NoError(t, err)
-	assert.Equal(t, 1, count)
-}
-
-func TestRPC_infoHndl(t *testing.T) {
-	_, port, teardown := prepTestStore(t)
-	defer teardown()
-	api := fmt.Sprintf("http://localhost:%d/test", port)
-
-	re := engine.RPC{Client: jrpc.Client{API: api, Client: http.Client{Timeout: 1 * time.Second}}}
-
-	c := store.Comment{ID: "123456", Locator: store.Locator{SiteID: "test-site", URL: "http://example.com/post1"},
-		Text: "text 123", User: store.User{ID: "u1", Name: "user1"}}
-	id, err := re.Create(c)
-	assert.NoError(t, err)
-	assert.Equal(t, "123456", id)
-
-	infoReq := engine.InfoRequest{Locator: store.Locator{SiteID: "test-site", URL: "http://example.com/post1"}}
-	info, err := re.Info(infoReq)
-	require.NoError(t, err)
-	assert.Equal(t, 1, len(info))
-	i := info[0]
-	assert.Equal(t, store.PostInfo{URL: "http://example.com/post1", Count: 1}, i)
-}
-
-func TestRPC_flagHndl(t *testing.T) {
-	_, port, teardown := prepTestStore(t)
-	defer teardown()
-	api := fmt.Sprintf("http://localhost:%d/test", port)
-
-	re := engine.RPC{Client: jrpc.Client{API: api, Client: http.Client{Timeout: 1 * time.Second}}}
-
-	c := store.Comment{ID: "123456", Locator: store.Locator{SiteID: "test-site", URL: "http://example.com/post1"},
-		Text: "text 123", User: store.User{ID: "u1", Name: "user1"}}
-	id, err := re.Create(c)
-	assert.NoError(t, err)
-	assert.Equal(t, "123456", id)
-
-	flagReq := engine.FlagRequest{
-		Flag: engine.Verified,
-		Locator: store.Locator{
-			SiteID: "test-site",
-		},
-		UserID: "u1",
-	}
-	status, err := re.Flag(flagReq)
-	require.NoError(t, err)
-	assert.Equal(t, false, status)
-
-	flagReq.Update = engine.FlagTrue
-	status, err = re.Flag(flagReq)
-	require.NoError(t, err)
-	assert.Equal(t, true, status)
-
-	flagReq.Update = engine.FlagNonSet
-	status, err = re.Flag(flagReq)
-	require.NoError(t, err)
-	assert.Equal(t, true, status)
-}
-
-func TestRPC_listFlagsHndl(t *testing.T) {
-	_, port, teardown := prepTestStore(t)
-	defer teardown()
-	api := fmt.Sprintf("http://localhost:%d/test", port)
-
-	re := engine.RPC{Client: jrpc.Client{API: api, Client: http.Client{Timeout: 1 * time.Second}}}
-
-	c := store.Comment{ID: "123456", Locator: store.Locator{SiteID: "test-site", URL: "http://example.com/post1"},
-		Text: "text 123", User: store.User{ID: "u1", Name: "user1"}}
-	id, err := re.Create(c)
-	assert.NoError(t, err)
-	assert.Equal(t, "123456", id)
-
-	flagReq := engine.FlagRequest{
-		Flag:   engine.Verified,
-		UserID: "u1",
-		Locator: store.Locator{
-			SiteID: "test-site",
-		},
-	}
-	flags, err := re.ListFlags(flagReq)
-	require.NoError(t, err)
-	assert.Equal(t, []interface{}{}, flags)
-
-	flagReq.Update = engine.FlagTrue
-	status, err := re.Flag(flagReq)
-	require.NoError(t, err)
-	assert.Equal(t, true, status)
-
-	flags, err = re.ListFlags(flagReq)
-	require.NoError(t, err)
-	assert.Equal(t, []interface{}{"u1"}, flags)
-}
-
-func TestRPC_userDetailHndl(t *testing.T) {
-	_, port, teardown := prepTestStore(t)
-	defer teardown()
-	api := fmt.Sprintf("http://localhost:%d/test", port)
-
-	re := engine.RPC{Client: jrpc.Client{API: api, Client: http.Client{Timeout: 1 * time.Second}}}
-
-	// add to entries to DB before we start
-	result, err := re.UserDetail(engine.UserDetailRequest{Locator: store.Locator{SiteID: "test-site"}, UserID: "u1", Detail: engine.UserEmail, Update: "test@example.com"})
-	assert.NoError(t, err, "No error inserting entry expected")
-	assert.ElementsMatch(t, []engine.UserDetailEntry{{UserID: "u1", Email: "test@example.com"}}, result)
-	result, err = re.UserDetail(engine.UserDetailRequest{Locator: store.Locator{SiteID: "test-site"}, UserID: "u2", Detail: engine.UserEmail, Update: "other@example.com"})
-	assert.NoError(t, err, "No error inserting entry expected")
-	assert.ElementsMatch(t, []engine.UserDetailEntry{{UserID: "u2", Email: "other@example.com"}}, result)
-
-	// try to change existing entry with wrong SiteID
-	result, err = re.UserDetail(engine.UserDetailRequest{Locator: store.Locator{SiteID: "bad"}, UserID: "u2", Detail: engine.UserEmail, Update: "not_relevant"})
-	assert.NoError(t, err, "Updating existing entry with wrong SiteID doesn't produce error")
-	assert.ElementsMatch(t, []engine.UserDetailEntry{}, result, "Updating existing entry with wrong SiteID doesn't change anything")
-
-	// stateless tests without changing the state we set up before
-	var testData = []struct {
-		req      engine.UserDetailRequest
-		error    string
-		expected []engine.UserDetailEntry
-	}{
-		{req: engine.UserDetailRequest{Locator: store.Locator{SiteID: "test-site"}, UserID: "u1", Detail: engine.UserEmail},
-			expected: []engine.UserDetailEntry{{UserID: "u1", Email: "test@example.com"}}},
-		{req: engine.UserDetailRequest{Locator: store.Locator{SiteID: "bad"}, UserID: "u1", Detail: engine.UserEmail},
-			expected: []engine.UserDetailEntry{}},
-		{req: engine.UserDetailRequest{Locator: store.Locator{SiteID: "test-site"}, UserID: "u1xyz", Detail: engine.UserEmail},
-			expected: []engine.UserDetailEntry{}},
-		{req: engine.UserDetailRequest{Detail: engine.UserEmail, Update: "new_value"},
-			error: `userid cannot be empty in request for single detail`},
-		{req: engine.UserDetailRequest{Detail: engine.UserDetail("bad")},
-			error: `unsupported detail "bad"`},
-		{req: engine.UserDetailRequest{Update: "not_relevant", Detail: engine.AllUserDetails},
-			error: `unsupported request with userdetail all`},
-		{req: engine.UserDetailRequest{Locator: store.Locator{SiteID: "test-site"}, Detail: engine.AllUserDetails},
-			expected: []engine.UserDetailEntry{{UserID: "u1", Email: "test@example.com"}, {UserID: "u2", Email: "other@example.com"}}},
-	}
-
-	for i, x := range testData {
-		result, err := re.UserDetail(x.req)
-		if x.error != "" {
-			assert.EqualError(t, err, x.error, "Error should match expected for case %d", i)
-		} else {
-			assert.NoError(t, err, "Error is not expected expected for case %d", i)
-		}
-		assert.ElementsMatch(t, x.expected, result, "Result should match expected for case %d", i)
-	}
-}
-
-func TestRPC_deleteHndl(t *testing.T) {
-	_, port, teardown := prepTestStore(t)
-	defer teardown()
-	api := fmt.Sprintf("http://localhost:%d/test", port)
-
-	re := engine.RPC{Client: jrpc.Client{API: api, Client: http.Client{Timeout: 1 * time.Second}}}
-	req := engine.DeleteRequest{
-		Locator:   store.Locator{SiteID: "test-site", URL: "http://example.com/post1"},
-		CommentID: "123456",
-	}
-
-	err := re.Delete(req)
-	assert.EqualError(t, err, "not found")
-
-	c := store.Comment{ID: "123456", Locator: store.Locator{SiteID: "test-site", URL: "http://example.com/post1"},
-		Text: "text 123", User: store.User{ID: "u1", Name: "user1"}}
-	_, err = re.Create(c)
-	assert.NoError(t, err)
-
-	err = re.Delete(req)
-	assert.NoError(t, err)
-}
-
-func TestRPC_closeHndl(t *testing.T) {
-	_, port, teardown := prepTestStore(t)
-	defer teardown()
-	api := fmt.Sprintf("http://localhost:%d/test", port)
-
-	re := engine.RPC{Client: jrpc.Client{API: api, Client: http.Client{Timeout: 1 * time.Second}}}
-	err := re.Close()
-	assert.NoError(t, err)
-}
-func TestRPC_admKeyHndl(t *testing.T) {
-	_, port, teardown := prepTestStore(t)
-	defer teardown()
-	api := fmt.Sprintf("http://localhost:%d/test", port)
-
-	ra := admin.RPC{Client: jrpc.Client{API: api, Client: http.Client{Timeout: 1 * time.Second}}}
-	key, err := ra.Key()
-	assert.NoError(t, err)
-	assert.Equal(t, "secret", key)
-}
-
-func TestRPC_admAdminsHndl(t *testing.T) {
-	_, port, teardown := prepTestStore(t)
-	defer teardown()
-	api := fmt.Sprintf("http://localhost:%d/test", port)
-
-	ra := admin.RPC{Client: jrpc.Client{API: api, Client: http.Client{Timeout: 1 * time.Second}}}
-	_, err := ra.Admins("bad site")
-	assert.EqualError(t, err, "site bad site not found")
-
-	admins, err := ra.Admins("test-site")
-	assert.NoError(t, err)
-	assert.Equal(t, []string{"id1", "id2"}, admins)
-}
-
-func TestRPC_admEmailHndl(t *testing.T) {
-	_, port, teardown := prepTestStore(t)
-	defer teardown()
-	api := fmt.Sprintf("http://localhost:%d/test", port)
-
-	ra := admin.RPC{Client: jrpc.Client{API: api, Client: http.Client{Timeout: 1 * time.Second}}}
-	_, err := ra.Admins("bad site")
-	assert.EqualError(t, err, "site bad site not found")
-
-	email, err := ra.Email("test-site")
-	assert.NoError(t, err)
-	assert.Equal(t, "admin@example.com", email)
-}
-
-func TestRPC_admEnabledHndl(t *testing.T) {
-	_, port, teardown := prepTestStore(t)
-	defer teardown()
-	api := fmt.Sprintf("http://localhost:%d/test", port)
-
-	ra := admin.RPC{Client: jrpc.Client{API: api, Client: http.Client{Timeout: 1 * time.Second}}}
-	_, err := ra.Enabled("bad site")
-	assert.EqualError(t, err, "site bad site not found")
-
-	ok, err := ra.Enabled("test-site")
-	assert.NoError(t, err)
-	assert.Equal(t, true, ok)
-
-	ok, err = ra.Enabled("test-site-disabled")
-	assert.NoError(t, err)
-	assert.Equal(t, false, ok)
-}
-
-func TestRPC_admEventHndl(t *testing.T) {
-	_, port, teardown := prepTestStore(t)
-	defer teardown()
-	api := fmt.Sprintf("http://localhost:%d/test", port)
-
-	ra := admin.RPC{Client: jrpc.Client{API: api, Client: http.Client{Timeout: 1 * time.Second}}}
-	err := ra.OnEvent("bad site", admin.EvCreate)
-	assert.EqualError(t, err, "site bad site not found")
-
-	err = ra.OnEvent("test-site", admin.EvCreate)
-	assert.NoError(t, err)
-}
-
 func chooseRandomUnusedPort() (port int) {
 	for i := 0; i < 10; i++ {
 		port = 40000 + int(rand.Int31n(10000))
diff --git a/backend/app/rest/api/rest_public.go b/backend/app/rest/api/rest_public.go
index efd86781..e53f6b9a 100644
--- a/backend/app/rest/api/rest_public.go
+++ b/backend/app/rest/api/rest_public.go
@@ -1,6 +1,7 @@
 package api
 
 import (
+	"bytes"
 	"crypto/sha1" // nolint
 	"encoding/base64"
 	"io"
@@ -436,7 +437,7 @@ func (s *public) loadPictureCtrl(w http.ResponseWriter, r *http.Request) {
 	}
 
 	id := chi.URLParam(r, "user") + "/" + chi.URLParam(r, "id")
-	imgRdr, size, err := s.imageService.Load(id)
+	img, err := s.imageService.Load(id)
 	if err != nil {
 		rest.SendErrorJSON(w, r, http.StatusBadRequest, err, "can't get image "+id, rest.ErrAssetNotFound)
 		return
@@ -452,16 +453,10 @@ func (s *public) loadPictureCtrl(w http.ResponseWriter, r *http.Request) {
 		}
 	}
 
-	defer func() {
-		if e := imgRdr.Close(); e != nil {
-			log.Printf("[WARN] failed to close reader for picture %s, %v", id, e)
-		}
-	}()
-
 	w.Header().Set("Content-Type", imgContentType(id))
-	w.Header().Set("Content-Length", strconv.Itoa(int(size)))
+	w.Header().Set("Content-Length", strconv.Itoa(len(img)))
 	w.WriteHeader(http.StatusOK)
-	if _, err = io.Copy(w, imgRdr); err != nil {
+	if _, err = io.Copy(w, bytes.NewReader(img)); err != nil {
 		log.Printf("[WARN] can't send response to %s, %s", r.RemoteAddr, err)
 	}
 }
diff --git a/backend/app/rest/proxy/image.go b/backend/app/rest/proxy/image.go
index c53c4880..3a5f7484 100644
--- a/backend/app/rest/proxy/image.go
+++ b/backend/app/rest/proxy/image.go
@@ -3,7 +3,7 @@ package proxy
 import (
 	"bytes"
 	"context"
-	"crypto/sha1" // nolint
+	"crypto/sha1" //nolint:gosec // not used for cryptography
 	"encoding/base64"
 	"fmt"
 	"io"
@@ -100,40 +100,25 @@ func (p Image) Handler(w http.ResponseWriter, r *http.Request) {
 	}
 
 	imgURL := string(src)
-	var imgReader io.ReadCloser
+	var img []byte
 	imgID, err := cachedImgID(imgURL)
 	if err != nil {
 		rest.SendErrorJSON(w, r, http.StatusBadRequest, err, "can't parse image url "+imgURL, rest.ErrAssetNotFound)
 		return
 	}
 	if p.CacheExternal {
-		imgReader, _, err = p.ImageService.Load(imgID)
-		if err != nil {
-			imgReader = nil
-		}
+		img, _ = p.ImageService.Load(imgID)
 	}
-	if imgReader == nil {
-		imgReader, err = p.downloadImage(context.Background(), imgURL)
+	if img == nil {
+		img, err = p.downloadImage(context.Background(), imgURL)
 		if err != nil {
 			rest.SendErrorJSON(w, r, http.StatusNotFound, err, "can't get image "+imgURL, rest.ErrAssetNotFound)
 			return
 		}
 		if p.CacheExternal {
-			var buf bytes.Buffer
-			// We need to duplicate data into a new buffer because `cacheImage` would read provider Reader
-			// and we would need another one to read data for response
-			p.cacheImage(io.TeeReader(imgReader, &buf), imgID)
-			if err := imgReader.Close(); err != nil {
-				log.Printf("[WARN] can't close image reader, %s", err)
-			}
-			imgReader = ioutil.NopCloser(&buf)
+			p.cacheImage(bytes.NewReader(img), imgID)
 		}
 	}
-	defer func() {
-		if e := imgReader.Close(); e != nil {
-			log.Printf("[WARN] can't close image reader, %s", e)
-		}
-	}()
 
 	// enforce client-side caching
 	etag := `"` + r.URL.Query().Get("src") + `"`
@@ -147,7 +132,7 @@ func (p Image) Handler(w http.ResponseWriter, r *http.Request) {
 	}
 
 	w.Header().Add("Content-Type", "image/*")
-	_, err = io.Copy(w, imgReader)
+	_, err = io.Copy(w, bytes.NewReader(img))
 	if err != nil {
 		log.Printf("[WARN] can't copy image stream, %s", err)
 	}
@@ -162,8 +147,8 @@ func (p Image) cacheImage(r io.Reader, imgID string) {
 	p.ImageService.Submit(func() []string { return []string{id} })
 }
 
-// download an image. Returns a Reader which has to be closed by a caller
-func (p Image) downloadImage(ctx context.Context, imgURL string) (io.ReadCloser, error) {
+// download an image.
+func (p Image) downloadImage(ctx context.Context, imgURL string) ([]byte, error) {
 	log.Printf("[DEBUG] downloading image %s", imgURL)
 
 	timeout := 60 * time.Second // default
@@ -197,11 +182,11 @@ func (p Image) downloadImage(ctx context.Context, imgURL string) (io.ReadCloser,
 	if err != nil {
 		return nil, errors.Errorf("unable to read image body")
 	}
-	return ioutil.NopCloser(bytes.NewBuffer(imgData)), nil
+	return imgData, nil
 }
 
 func sha1Str(s string) string {
-	return fmt.Sprintf("%x", sha1.Sum([]byte(s))) // nolint
+	return fmt.Sprintf("%x", sha1.Sum([]byte(s))) //nolint:gosec // not used for cryptography
 }
 
 // generates ID for a cached image.
diff --git a/backend/app/rest/proxy/image_test.go b/backend/app/rest/proxy/image_test.go
index 0122bd25..8b1ce808 100644
--- a/backend/app/rest/proxy/image_test.go
+++ b/backend/app/rest/proxy/image_test.go
@@ -1,7 +1,6 @@
 package proxy
 
 import (
-	"bytes"
 	"encoding/base64"
 	"fmt"
 	"io"
@@ -16,6 +15,7 @@ import (
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/mock"
 	"github.com/stretchr/testify/require"
+
 	"github.com/umputun/remark/backend/app/store/image"
 )
 
@@ -112,9 +112,9 @@ func TestImage_RoutesCachingImage(t *testing.T) {
 	imgURL := httpSrv.URL + "/image/img1.png"
 	encodedImgURL := base64.URLEncoding.EncodeToString([]byte(imgURL))
 
-	imageStore.On("Load", mock.Anything).Once().Return(nil, int64(0), nil)
+	imageStore.On("Load", mock.Anything).Once().Return(nil, nil)
 	imageStore.On("SaveWithID", mock.Anything, mock.Anything).Once().Run(func(args mock.Arguments) { _, _ = ioutil.ReadAll(args.Get(1).(io.Reader)) }).Return("", nil)
-	imageStore.On("commit", mock.Anything).Once().Return(nil)
+	imageStore.On("Commit", mock.Anything).Once().Return(nil)
 
 	resp, err := http.Get(ts.URL + "/?src=" + encodedImgURL)
 	require.Nil(t, err)
@@ -124,7 +124,7 @@ func TestImage_RoutesCachingImage(t *testing.T) {
 
 	imageStore.AssertCalled(t, "Load", mock.Anything)
 	imageStore.AssertCalled(t, "SaveWithID", "cached_images/4b84b15bff6ee5796152495a230e45e3d7e947d9-"+sha1Str(imgURL), mock.Anything)
-	imageStore.AssertCalled(t, "commit", mock.Anything)
+	imageStore.AssertCalled(t, "Commit", mock.Anything)
 }
 
 func TestImage_RoutesUsingCachedImage(t *testing.T) {
@@ -144,8 +144,8 @@ func TestImage_RoutesUsingCachedImage(t *testing.T) {
 	encodedImgURL := base64.URLEncoding.EncodeToString([]byte(httpSrv.URL + "/image/img1.png"))
 
 	// In order to validate that cached data used cache "will return" some other data from what http server would
-	imageReader := ioutil.NopCloser(bytes.NewReader([]byte(fmt.Sprintf("%256s", "X"))))
-	imageStore.On("Load", mock.Anything).Once().Return(imageReader, int64(256), nil)
+	testImage := []byte(fmt.Sprintf("%256s", "X"))
+	imageStore.On("Load", mock.Anything).Once().Return(testImage, nil)
 
 	resp, err := http.Get(ts.URL + "/?src=" + encodedImgURL)
 	require.Nil(t, err)
diff --git a/backend/app/store/engine/engine_mock.go b/backend/app/store/engine/engine_mock.go
index 603373da..47a66e3b 100644
--- a/backend/app/store/engine/engine_mock.go
+++ b/backend/app/store/engine/engine_mock.go
@@ -2,10 +2,8 @@
 
 package engine
 
-import (
-	mock "github.com/stretchr/testify/mock"
-	store "github.com/umputun/remark/backend/app/store"
-)
+import mock "github.com/stretchr/testify/mock"
+import store "github.com/umputun/remark/backend/app/store"
 
 // MockInterface is an autogenerated mock type for the Interface type
 type MockInterface struct {
diff --git a/backend/app/store/image/bolt_store.go b/backend/app/store/image/bolt_store.go
index e9588006..f1d13a1c 100644
--- a/backend/app/store/image/bolt_store.go
+++ b/backend/app/store/image/bolt_store.go
@@ -5,7 +5,6 @@ import (
 	"context"
 	"encoding/binary"
 	"io"
-	"io/ioutil"
 	"path"
 	"time"
 
@@ -93,8 +92,8 @@ func (b *Bolt) Save(_ string, userID string, r io.Reader) (id string, err error)
 }
 
 // Commit file stored in staging bucket by copying it to permanent bucket
-// Data from staging bucket not removed immediately, but would be removed on cleanup
-func (b *Bolt) commit(id string) error {
+// Data from staging bucket not removed immediately, but would be removed on Cleanup
+func (b *Bolt) Commit(id string) error {
 	err := b.db.Update(func(tx *bolt.Tx) error {
 		data := tx.Bucket([]byte(imagesStagedBktName)).Get([]byte(id))
 		if data == nil {
@@ -107,27 +106,27 @@ func (b *Bolt) commit(id string) error {
 }
 
 // Load image from DB
-// returns ReadCloser and caller should call close after processing completed.
-func (b *Bolt) Load(id string) (io.ReadCloser, int64, error) {
-	buf := &bytes.Buffer{}
-	var size int = 0
+func (b *Bolt) Load(id string) ([]byte, error) {
+	var data []byte
 	err := b.db.View(func(tx *bolt.Tx) error {
-		data := tx.Bucket([]byte(imagesBktName)).Get([]byte(id))
+		data = tx.Bucket([]byte(imagesBktName)).Get([]byte(id))
 		if data == nil {
 			data = tx.Bucket([]byte(imagesStagedBktName)).Get([]byte(id))
 		}
 		if data == nil {
 			return errors.Errorf("can't load image %s", id)
 		}
-		var err error
-		size, err = buf.Write(data)
-		return errors.Wrapf(err, "failed to write for %s", id)
+		return nil
 	})
-	return ioutil.NopCloser(buf), int64(size), err
+	if err != nil {
+		// separate error handler to return nil and not empty []byte
+		return nil, err
+	}
+	return data, nil
 }
 
 // Cleanup runs scan of staging and removes old data based on ttl
-func (b *Bolt) cleanup(_ context.Context, ttl time.Duration) error {
+func (b *Bolt) Cleanup(_ context.Context, ttl time.Duration) error {
 	err := b.db.Update(func(tx *bolt.Tx) error {
 		c := tx.Bucket([]byte(insertTimeBktName)).Cursor()
 
diff --git a/backend/app/store/image/bolt_store_test.go b/backend/app/store/image/bolt_store_test.go
index d206c49a..27e01fed 100644
--- a/backend/app/store/image/bolt_store_test.go
+++ b/backend/app/store/image/bolt_store_test.go
@@ -31,7 +31,7 @@ func TestBoltStore_SaveCommit(t *testing.T) {
 	})
 	assert.NoError(t, err)
 
-	err = svc.commit(id)
+	err = svc.Commit(id)
 	require.NoError(t, err)
 
 	err = svc.db.View(func(tx *bolt.Tx) error {
@@ -53,16 +53,11 @@ func TestBoltStore_LoadAfterSave(t *testing.T) {
 	assert.Contains(t, id, "user1")
 	t.Log(id)
 
-	r, sz, err := svc.Load(id)
-	assert.NoError(t, err)
-	defer func() { assert.NoError(t, r.Close()) }()
-	data, err := ioutil.ReadAll(r)
-
+	data, err := svc.Load(id)
 	assert.NoError(t, err)
 	assert.Equal(t, 1462, len(data))
-	assert.Equal(t, int64(1462), sz)
 
-	_, _, err = svc.Load("abcd")
+	_, err = svc.Load("abcd")
 	assert.Error(t, err)
 }
 
@@ -90,7 +85,7 @@ func TestBoltStore_Cleanup(t *testing.T) {
 	time.Sleep(100 * time.Millisecond)
 	img3 := save("blah_ff3.png", "user2")
 
-	err := svc.cleanup(context.Background(), time.Since(img1ts)) // clean first images
+	err := svc.Cleanup(context.Background(), time.Since(img1ts)) // clean first images
 	assert.NoError(t, err)
 
 	assertBoltImgNil(t, svc.db, imagesStagedBktName, img1)
@@ -98,10 +93,10 @@ func TestBoltStore_Cleanup(t *testing.T) {
 	assertBoltImgNotNil(t, svc.db, imagesStagedBktName, img2)
 	assertBoltImgNotNil(t, svc.db, imagesStagedBktName, img3)
 
-	err = svc.commit(img3)
+	err = svc.Commit(img3)
 	require.NoError(t, err)
 
-	err = svc.cleanup(context.Background(), time.Millisecond*10)
+	err = svc.Cleanup(context.Background(), time.Millisecond*10)
 	assert.NoError(t, err)
 
 	assertBoltImgNil(t, svc.db, imagesStagedBktName, img2)
diff --git a/backend/app/store/image/fs_store.go b/backend/app/store/image/fs_store.go
index ab9b4a05..80377d6b 100644
--- a/backend/app/store/image/fs_store.go
+++ b/backend/app/store/image/fs_store.go
@@ -70,8 +70,8 @@ func (f *FileSystem) Save(fileName string, userID string, r io.Reader) (id strin
 }
 
 // Commit file stored in staging location by moving it to permanent location
-func (f *FileSystem) commit(id string) error {
-	log.Printf("[DEBUG] commit image %s", id)
+func (f *FileSystem) Commit(id string) error {
+	log.Printf("[DEBUG] Commit image %s", id)
 	stagingImage, permImage := f.location(f.Staging, id), f.location(f.Location, id)
 
 	if err := os.MkdirAll(path.Dir(permImage), 0700); err != nil {
@@ -83,34 +83,33 @@ func (f *FileSystem) commit(id string) error {
 }
 
 // Load image from FS. Uses id to get partition subdirectory.
-// returns ReadCloser and caller should call close after processing completed.
-func (f *FileSystem) Load(id string) (io.ReadCloser, int64, error) {
+func (f *FileSystem) Load(id string) ([]byte, error) {
 
 	// get image file by id. first try permanent location and if not found - staging
-	img := func(id string) (file string, st os.FileInfo, err error) {
+	img := func(id string) (file string, err error) {
 		file = f.location(f.Location, id)
-		st, err = os.Stat(file)
+		_, err = os.Stat(file)
 		if err != nil {
 			file = f.location(f.Staging, id)
-			st, err = os.Stat(file)
+			_, err = os.Stat(file)
 		}
-		return file, st, errors.Wrapf(err, "can't get image stats for %s", id)
+		return file, errors.Wrapf(err, "can't get image stats for %s", id)
 	}
 
-	imgFile, st, err := img(id)
+	imgFile, err := img(id)
 	if err != nil {
-		return nil, 0, errors.Wrapf(err, "can't get image file for %s", id)
+		return nil, errors.Wrapf(err, "can't get image file for %s", id)
 	}
 
-	fh, err := os.Open(imgFile) // nolint
+	fh, err := os.Open(imgFile) //nolint:gosec
 	if err != nil {
-		return nil, 0, errors.Wrapf(err, "can't load image %s", id)
+		return nil, errors.Wrapf(err, "can't load image %s", id)
 	}
-	return fh, st.Size(), nil
+	return ioutil.ReadAll(fh)
 }
 
 // Cleanup runs scan of staging and removes old files based on ttl
-func (f *FileSystem) cleanup(_ context.Context, ttl time.Duration) error {
+func (f *FileSystem) Cleanup(_ context.Context, ttl time.Duration) error {
 
 	if _, err := os.Stat(f.Staging); os.IsNotExist(err) {
 		return nil
diff --git a/backend/app/store/image/fs_store_test.go b/backend/app/store/image/fs_store_test.go
index 08926301..d2077d81 100644
--- a/backend/app/store/image/fs_store_test.go
+++ b/backend/app/store/image/fs_store_test.go
@@ -129,7 +129,7 @@ func TestFsStore_SaveAndCommit(t *testing.T) {
 
 	id, err := svc.Save("file1.png", "user1", gopherPNG())
 	require.NoError(t, err)
-	err = svc.commit(id)
+	err = svc.Commit(id)
 	require.NoError(t, err)
 
 	imgStaging := svc.location(svc.Staging, id)
@@ -161,14 +161,10 @@ func TestFsStore_LoadAfterSave(t *testing.T) {
 	assert.NoError(t, err)
 	t.Log(id)
 
-	r, sz, err := svc.Load(id)
-	assert.NoError(t, err)
-	defer func() { assert.NoError(t, r.Close()) }()
-	data, err := ioutil.ReadAll(r)
+	data, err := svc.Load(id)
 	assert.NoError(t, err)
 	assert.Equal(t, 1462, len(data))
-	assert.Equal(t, int64(1462), sz)
-	_, _, err = svc.Load("abcd")
+	_, err = svc.Load("abcd")
 	assert.Error(t, err)
 }
 
@@ -180,17 +176,13 @@ func TestFsStore_LoadAfterCommit(t *testing.T) {
 	id, err := svc.Save("blah_ff1.png", "user1", gopherPNG())
 	assert.NoError(t, err)
 	t.Log(id)
-	err = svc.commit(id)
+	err = svc.Commit(id)
 	require.NoError(t, err)
 
-	r, sz, err := svc.Load(id)
-	assert.NoError(t, err)
-	defer func() { assert.NoError(t, r.Close()) }()
-	data, err := ioutil.ReadAll(r)
+	data, err := svc.Load(id)
 	assert.NoError(t, err)
 	assert.Equal(t, 1462, len(data))
-	assert.Equal(t, int64(1462), sz)
-	_, _, err = svc.Load("abcd")
+	_, err = svc.Load("abcd")
 	assert.Error(t, err)
 }
 
@@ -260,13 +252,13 @@ func TestFsStore_Cleanup(t *testing.T) {
 	img3 := save("blah_ff3.png", "user2")
 
 	time.Sleep(200 * time.Millisecond) // make first image expired
-	err := svc.cleanup(context.Background(), time.Millisecond*300)
+	err := svc.Cleanup(context.Background(), time.Millisecond*300)
 	assert.NoError(t, err)
 
 	_, err = os.Stat(img1)
 	assert.Error(t, err, "no file on staging anymore")
 	// sometimes two images for user1 are put into same directory, which means that
-	// after first image cleanup it's not empty and won't be deleted
+	// after first image Cleanup it's not empty and won't be deleted
 	_, err = os.Stat(path.Dir(img1))
 	if path.Dir(img1) != path.Dir(img2) {
 		assert.Error(t, err, "no dir %s on staging anymore", path.Dir(img1))
@@ -280,7 +272,7 @@ func TestFsStore_Cleanup(t *testing.T) {
 	assert.NoError(t, err, "file on staging")
 
 	time.Sleep(200 * time.Millisecond) // make all images expired
-	err = svc.cleanup(context.Background(), time.Millisecond*300)
+	err = svc.Cleanup(context.Background(), time.Millisecond*300)
 	assert.NoError(t, err)
 
 	_, err = os.Stat(img2)
diff --git a/backend/app/store/image/image.go b/backend/app/store/image/image.go
index a229cf86..7a55e5f6 100644
--- a/backend/app/store/image/image.go
+++ b/backend/app/store/image/image.go
@@ -41,16 +41,19 @@ type Service struct {
 	term     int32 // term value used atomically to detect emergency termination
 }
 
+// To regenerate mock run from this directory:
+// sh -c "mockery -inpkg -name Store -print > /tmp/image-mock.tmp && mv /tmp/image-mock.tmp image_mock.go"
+
 // Store defines interface for saving and loading pictures.
-// Declares two-stage save with commit. Save stores to staging area and Commit moves to the final location
+// Declares two-stage save with Commit. Save stores to staging area and Commit moves to the final location
 type Store interface {
 	Save(fileName string, userID string, r io.Reader) (id string, err error) // get name and reader and returns ID of stored (staging) image
 	SaveWithID(id string, r io.Reader) (string, error)                       // store image for passed id to staging
-	Load(id string) (io.ReadCloser, int64, error)                            // load image by ID. Caller has to close the reader.
+	Load(id string) ([]byte, error)                                          // load image by ID. Caller has to close the reader.
 	SizeLimit() int                                                          // max image size
 
-	commit(id string) error                               // move image from staging to permanent
-	cleanup(ctx context.Context, ttl time.Duration) error // run removal loop for old images on staging
+	Commit(id string) error                               // move image from staging to permanent
+	Cleanup(ctx context.Context, ttl time.Duration) error // run removal loop for old images on staging
 }
 
 const submitQueueSize = 5000
@@ -78,7 +81,7 @@ func (s *Service) Submit(idsFn func() []string) {
 					time.Sleep(time.Millisecond * 10) // small sleep to relive busy wait but keep reactive for term (close)
 				}
 				for _, id := range req.idsFn() {
-					if err := s.commit(id); err != nil {
+					if err := s.Commit(id); err != nil {
 						log.Printf("[WARN] failed to commit image %s", id)
 					}
 				}
@@ -124,7 +127,7 @@ func (s *Service) Cleanup(ctx context.Context) {
 			log.Printf("[INFO] cleanup terminated, %v", ctx.Err())
 			return
 		case <-time.After(s.TTL / 2): // cleanup call on every 1/2 TTL
-			if err := s.Store.cleanup(ctx, s.TTL); err != nil {
+			if err := s.Store.Cleanup(ctx, s.TTL); err != nil {
 				log.Printf("[WARN] failed to cleanup, %v", err)
 			}
 		}
@@ -136,7 +139,7 @@ func (s *Service) Close() {
 	log.Printf("[INFO] close image service ")
 	atomic.StoreInt32(&s.term, 1) // enforce non-delayed commits for all ids left in submitCh
 	for {
-		// set to 0 by commit goroutine after everything waited on TTL sent
+		// set to 0 by Commit goroutine after everything waited on TTL sent
 		if atomic.LoadInt32(&s.term) == 0 {
 			break
 		}
diff --git a/backend/app/store/image/image_mock.go b/backend/app/store/image/image_mock.go
index 3ab8c2b5..8c23293c 100644
--- a/backend/app/store/image/image_mock.go
+++ b/backend/app/store/image/image_mock.go
@@ -2,48 +2,65 @@
 
 package image
 
-import (
-	context "context"
-	io "io"
-
-	mock "github.com/stretchr/testify/mock"
-
-	time "time"
-)
+import context "context"
+import io "io"
+import mock "github.com/stretchr/testify/mock"
+import time "time"
 
 // MockStore is an autogenerated mock type for the Store type
 type MockStore struct {
 	mock.Mock
 }
 
-// Load provides a mock function with given fields: id
-func (_m *MockStore) Load(id string) (io.ReadCloser, int64, error) {
+// Cleanup provides a mock function with given fields: ctx, ttl
+func (_m *MockStore) Cleanup(ctx context.Context, ttl time.Duration) error {
+	ret := _m.Called(ctx, ttl)
+
+	var r0 error
+	if rf, ok := ret.Get(0).(func(context.Context, time.Duration) error); ok {
+		r0 = rf(ctx, ttl)
+	} else {
+		r0 = ret.Error(0)
+	}
+
+	return r0
+}
+
+// Commit provides a mock function with given fields: id
+func (_m *MockStore) Commit(id string) error {
 	ret := _m.Called(id)
 
-	var r0 io.ReadCloser
-	if rf, ok := ret.Get(0).(func(string) io.ReadCloser); ok {
+	var r0 error
+	if rf, ok := ret.Get(0).(func(string) error); ok {
+		r0 = rf(id)
+	} else {
+		r0 = ret.Error(0)
+	}
+
+	return r0
+}
+
+// Load provides a mock function with given fields: id
+func (_m *MockStore) Load(id string) ([]byte, error) {
+	ret := _m.Called(id)
+
+	var r0 []byte
+	if rf, ok := ret.Get(0).(func(string) []byte); ok {
 		r0 = rf(id)
 	} else {
 		if ret.Get(0) != nil {
-			r0 = ret.Get(0).(io.ReadCloser)
+			r0 = ret.Get(0).([]byte)
 		}
 	}
 
-	var r1 int64
-	if rf, ok := ret.Get(1).(func(string) int64); ok {
+	var r1 error
+	if rf, ok := ret.Get(1).(func(string) error); ok {
 		r1 = rf(id)
 	} else {
-		r1 = ret.Get(1).(int64)
+		r1 = ret.Error(1)
 	}
 
-	var r2 error
-	if rf, ok := ret.Get(2).(func(string) error); ok {
-		r2 = rf(id)
-	} else {
-		r2 = ret.Error(2)
-	}
-
-	return r0, r1, r2
+	return r0, r1
 }
 
 // Save provides a mock function with given fields: fileName, userID, r
@@ -101,31 +118,3 @@ func (_m *MockStore) SizeLimit() int {
 
 	return r0
 }
-
-// cleanup provides a mock function with given fields: ctx, ttl
-func (_m *MockStore) cleanup(ctx context.Context, ttl time.Duration) error {
-	ret := _m.Called(ctx, ttl)
-
-	var r0 error
-	if rf, ok := ret.Get(0).(func(context.Context, time.Duration) error); ok {
-		r0 = rf(ctx, ttl)
-	} else {
-		r0 = ret.Error(0)
-	}
-
-	return r0
-}
-
-// commit provides a mock function with given fields: id
-func (_m *MockStore) commit(id string) error {
-	ret := _m.Called(id)
-
-	var r0 error
-	if rf, ok := ret.Get(0).(func(string) error); ok {
-		r0 = rf(id)
-	} else {
-		r0 = ret.Error(0)
-	}
-
-	return r0
-}
diff --git a/backend/app/store/image/image_test.go b/backend/app/store/image/image_test.go
index 5a7a7c4d..5d55789c 100644
--- a/backend/app/store/image/image_test.go
+++ b/backend/app/store/image/image_test.go
@@ -37,49 +37,49 @@ func TestService_ExtractPictures2(t *testing.T) {
 
 func TestService_Cleanup(t *testing.T) {
 	store := MockStore{}
-	store.On("cleanup", mock.Anything, mock.Anything).Times(10).Return(nil)
+	store.On("Cleanup", mock.Anything, mock.Anything).Times(10).Return(nil)
 
 	svc := Service{Store: &store, TTL: 100 * time.Millisecond}
 	ctx, cancel := context.WithTimeout(context.Background(), time.Millisecond*549)
 	defer cancel()
 	svc.Cleanup(ctx)
-	store.AssertNumberOfCalls(t, "cleanup", 10)
+	store.AssertNumberOfCalls(t, "Cleanup", 10)
 }
 
 func TestService_Submit(t *testing.T) {
 	store := MockStore{}
-	store.On("commit", mock.Anything, mock.Anything).Times(5).Return(nil)
+	store.On("Commit", mock.Anything, mock.Anything).Times(5).Return(nil)
 	svc := Service{Store: &store, ImageAPI: "/blah/", TTL: time.Millisecond * 100}
 	svc.Submit(func() []string { return []string{"id1", "id2", "id3"} })
 	svc.Submit(func() []string { return []string{"id4", "id5"} })
 	svc.Submit(nil)
-	store.AssertNumberOfCalls(t, "commit", 0)
+	store.AssertNumberOfCalls(t, "Commit", 0)
 	time.Sleep(time.Millisecond * 150)
-	store.AssertNumberOfCalls(t, "commit", 5)
+	store.AssertNumberOfCalls(t, "Commit", 5)
 }
 
 func TestService_Close(t *testing.T) {
 	store := MockStore{}
-	store.On("commit", mock.Anything, mock.Anything).Times(5).Return(nil)
+	store.On("Commit", mock.Anything, mock.Anything).Times(5).Return(nil)
 	svc := Service{Store: &store, ImageAPI: "/blah/", TTL: time.Millisecond * 500}
 	svc.Submit(func() []string { return []string{"id1", "id2", "id3"} })
 	svc.Submit(func() []string { return []string{"id4", "id5"} })
 	svc.Submit(nil)
 	svc.Close()
-	store.AssertNumberOfCalls(t, "commit", 5)
+	store.AssertNumberOfCalls(t, "Commit", 5)
 }
 
 func TestService_SubmitDelay(t *testing.T) {
 	store := MockStore{}
-	store.On("commit", mock.Anything, mock.Anything).Times(5).Return(nil)
+	store.On("Commit", mock.Anything, mock.Anything).Times(5).Return(nil)
 	svc := Service{Store: &store, ImageAPI: "/blah/", TTL: time.Millisecond * 100}
 	svc.Submit(func() []string { return []string{"id1", "id2", "id3"} })
 	time.Sleep(150 * time.Millisecond) // let first batch to pass TTL
 	svc.Submit(func() []string { return []string{"id4", "id5"} })
 	svc.Submit(nil)
-	store.AssertNumberOfCalls(t, "commit", 3)
+	store.AssertNumberOfCalls(t, "Commit", 3)
 	svc.Close()
-	store.AssertNumberOfCalls(t, "commit", 5)
+	store.AssertNumberOfCalls(t, "Commit", 5)
 }
 
 func TestService_resize(t *testing.T) {
diff --git a/backend/app/store/service/service_test.go b/backend/app/store/service/service_test.go
index d4ba3700..bf15b6dc 100644
--- a/backend/app/store/service/service_test.go
+++ b/backend/app/store/service/service_test.go
@@ -1277,7 +1277,7 @@ func TestService_submitImages(t *testing.T) {
 	lgr.Setup(lgr.Debug, lgr.CallerFile, lgr.CallerFunc)
 
 	mockStore := image.MockStore{}
-	mockStore.On("commit", mock.Anything, mock.Anything).Times(2).Return(nil)
+	mockStore.On("Commit", mock.Anything, mock.Anything).Times(2).Return(nil)
 	imgSvc := &image.Service{Store: &mockStore, TTL: time.Millisecond * 50}
 
 	// two comments for https://radio-t.com