diff --git a/app/rest/api/rest.go b/app/rest/api/rest.go
index cf871921..40abed6d 100644
--- a/app/rest/api/rest.go
+++ b/app/rest/api/rest.go
@@ -138,6 +138,12 @@ func (s *Rest) createCommentCtrl(w http.ResponseWriter, r *http.Request) {
 	comment.PrepareUntrusted() // clean all fields user not suppoed to set
 	comment.User = user
 	comment.User.IP = strings.Split(r.RemoteAddr, ":")[0]
+
+	if comment.Validate() != nil {
+		rest.SendErrorJSON(w, r, http.StatusBadRequest, err, "invalid comment")
+		return
+	}
+
 	comment.Text = string(blackfriday.Run([]byte(comment.Text), blackfriday.WithExtensions(mdExt)))
 	log.Printf("[DEBUG] create comment %+v", comment)
 
@@ -165,6 +171,17 @@ func (s *Rest) previewCommentCtrl(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
+	user, err := rest.GetUserInfo(r)
+	if err != nil { // this not suppose to happen (handled by Auth), just dbl-check
+		rest.SendErrorJSON(w, r, http.StatusUnauthorized, err, "can't get user info")
+		return
+	}
+	comment.User = user
+	if err := comment.Validate(); err != nil {
+		rest.SendErrorJSON(w, r, http.StatusBadRequest, err, "invalid comment")
+		return
+	}
+
 	comment.Text = string(blackfriday.Run([]byte(comment.Text), blackfriday.WithExtensions(mdExt)))
 	comment.Sanitize()
 	render.HTML(w, r, comment.Text)
diff --git a/app/rest/api/rest_test.go b/app/rest/api/rest_test.go
index 62cdee3d..831f0c88 100644
--- a/app/rest/api/rest_test.go
+++ b/app/rest/api/rest_test.go
@@ -63,7 +63,7 @@ func TestServer_Preview(t *testing.T) {
 	defer cleanup(srv)
 
 	r := strings.NewReader(`{"text": "test 123", "locator":{"url": "https://radio-t.com/blah1", "site": "radio-t"}}`)
-	resp, err := http.Post(fmt.Sprintf("http://127.0.0.1:%d/api/v1/preview", port), "application/json", r)
+	resp, err := http.Post(fmt.Sprintf("http://dev:password@127.0.0.1:%d/api/v1/preview", port), "application/json", r)
 	assert.Equal(t, http.StatusOK, resp.StatusCode)
 	b, err := ioutil.ReadAll(resp.Body)
 	assert.Nil(t, err)
@@ -90,7 +90,7 @@ BKT
 	j = strings.Replace(j, "\n", "\\n", -1)
 	t.Log(j)
 	r := strings.NewReader(j)
-	resp, err := http.Post(fmt.Sprintf("http://127.0.0.1:%d/api/v1/preview", port), "application/json", r)
+	resp, err := http.Post(fmt.Sprintf("http://dev:password@127.0.0.1:%d/api/v1/preview", port), "application/json", r)
 	assert.Equal(t, http.StatusOK, resp.StatusCode)
 	b, err := ioutil.ReadAll(resp.Body)
 	assert.Nil(t, err)
diff --git a/app/store/comment.go b/app/store/comment.go
index de1b551d..28c461aa 100644
--- a/app/store/comment.go
+++ b/app/store/comment.go
@@ -3,6 +3,7 @@ package store
 import (
 	"crypto/hmac"
 	"crypto/sha1"
+	"errors"
 	"fmt"
 	"html/template"
 	"log"
@@ -62,6 +63,9 @@ type BlockedUser struct {
 	Timestamp time.Time `json:"time"`
 }
 
+// MaxCommentSize defines max size of comment's text
+const MaxCommentSize = 2048
+
 // PrepareUntrusted preprocess comment received from untrusted source by clearing all
 // autogen fields and reset everything users not supposed to provide
 func (c *Comment) PrepareUntrusted() {
@@ -95,6 +99,20 @@ func (c *Comment) Sanitize() {
 	// c.Text = strings.Replace(c.Text, "\t", "", -1)
 }
 
+// Validate comment
+func (c *Comment) Validate() error {
+	if c.Text == "" {
+		return errors.New("empty comment text")
+	}
+	if len(c.Text) > MaxCommentSize {
+		return errors.New("comment text exceeded max allowed size")
+	}
+	if c.User.ID == "" || c.User.Name == "" {
+		return errors.New("empty user info")
+	}
+	return nil
+}
+
 // hashIP replace sensitive fields with hashes
 func (u *User) hashIP(secret string) {
 
diff --git a/app/store/comment_test.go b/app/store/comment_test.go
index 33713083..0180c80f 100644
--- a/app/store/comment_test.go
+++ b/app/store/comment_test.go
@@ -4,6 +4,7 @@ import (
 	"testing"
 	"time"
 
+	"github.com/pkg/errors"
 	"github.com/stretchr/testify/assert"
 )
 
@@ -32,6 +33,31 @@ func TestComment_Sanitize(t *testing.T) {
 	}
 }
 
+func TestComment_Validate(t *testing.T) {
+	longText := ""
+	for i := 0; i < 4000; i++ {
+		longText += "X"
+	}
+	tbl := []struct {
+		inp Comment
+		err error
+	}{
+		{inp: Comment{}, err: errors.New("empty comment text")},
+		{inp: Comment{Text: "something blah", User: User{ID: "myid", Name: "name"}}, err: nil},
+		{inp: Comment{Text: "something blah", User: User{ID: "myid"}}, err: errors.New("empty user info")},
+		{inp: Comment{Text: longText, User: User{ID: "myid", Name: "name"}}, err: errors.New("comment text exceeded max allowed size")},
+	}
+
+	for n, tt := range tbl {
+		e := tt.inp.Validate()
+		if tt.err == nil {
+			assert.Nil(t, e, "check #%d", n)
+			continue
+		}
+		assert.EqualError(t, tt.err, e.Error(), "check #%d", n)
+	}
+}
+
 func TestComment_PrepareUntrusted(t *testing.T) {
 	comment := Comment{
 		Text:      `blah`,