diff --git a/README.md b/README.md
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+++ b/README.md
@@ -21,6 +21,7 @@ One `weed` binary serves an S3 object store, a POSIX file system, and a lakehous
 
 - [Download Binaries for different platforms](https://github.com/seaweedfs/seaweedfs/releases/latest)
 - [Wiki Documentation](https://github.com/seaweedfs/seaweedfs/wiki)
+- [HTTP REST API](REST_API.md) for the filer, master, and volume servers
 - Community: [Slack](https://join.slack.com/t/seaweedfs/shared_invite/enQtMzI4MTMwMjU2MzA3LTEyYzZmZWYzOGQ3MDJlZWMzYmI0OTE4OTJiZjJjODBmMzUxNmYwODg0YjY3MTNlMjBmZDQ1NzQ5NDJhZWI2ZmY), [Twitter](https://twitter.com/SeaweedFS), [Telegram](https://t.me/Seaweedfs), [Reddit](https://www.reddit.com/r/SeaweedFS/), [Mailing List](https://groups.google.com/d/forum/seaweedfs)
 - [SeaweedFS White Paper](https://github.com/seaweedfs/seaweedfs/wiki/SeaweedFS_Architecture.pdf) and introduction slides: [2025.5](https://docs.google.com/presentation/d/1tdkp45J01oRV68dIm4yoTXKJDof-EhainlA0LMXexQE/edit?usp=sharing), [2021.5](https://docs.google.com/presentation/d/1DcxKWlINc-HNCjhYeERkpGXXm6nTCES8mi2W5G0Z4Ts/edit?usp=sharing), [2019.3](https://www.slideshare.net/chrislusf/seaweedfs-introduction)
 
diff --git a/REST_API.md b/REST_API.md
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+# SeaweedFS HTTP REST API
+
+SeaweedFS exposes three HTTP surfaces:
+
+| Service | Default port | Addressing |
+|---------|--------------|------------|
+| Filer | 8888 | File system paths (`/dir/name`) |
+| Master | 9333 | File id assignment and cluster topology |
+| Volume server | 8080 | File content by file id (`vid,fid`) |
+
+Most clients only need the filer API (paths) or the S3 API. The master and
+volume APIs are the lower-level blob store interface.
+
+Conventions applying to all three:
+
+- Responses are JSON unless noted otherwise. Append `&pretty=y` to pretty-print.
+- A file id (`fid`) has the form `volumeId,fileKeyCookie`, e.g. `3,01637037d6`.
+  An optional suffix selects a reserved id from a `count` assignment
+  (`3,01637037d6_1`, `_2`, ...), and an optional extension
+  (`3,01637037d6.jpg`) sets the content type on reads.
+- `replication` is a 3-digit replica placement `xyz`: `x` copies in other
+  data centers, `y` on other racks in the same data center, `z` on other
+  volume servers on the same rack. `000` = no replication, `001` = one copy
+  on the same rack, `010` = one copy on a different rack, `100` = one copy in
+  another data center, `200` = two copies in two other data centers, `110` =
+  one copy in another data center plus one on another rack.
+- `ttl` units: `m` minute, `h` hour, `d` day, `w` week, `M` month, `y` year.
+
+## Filer API (port 8888)
+
+The filer presents a POSIX-like namespace over the volume servers.
+
+### Upload a file
+
+```bash
+# PUT the raw body to the target path
+curl -T /home/chris/myphoto.jpg "http://localhost:8888/dir/myphoto.jpg"
+
+# or POST as multipart form (the part filename becomes the entry name)
+curl -F file=@/home/chris/myphoto.jpg "http://localhost:8888/dir/"
+```
+
+Response `201 Created`:
+
+```json
+{"name":"myphoto.jpg","size":43234,"eTag":"0x6c656...","mtime":"...","chunks":[...]}
+```
+
+Query parameters:
+
+| Parameter | Description | Default |
+|-----------|-------------|---------|
+| `collection` | collection name | empty |
+| `replication` | replica placement code | filer default |
+| `ttl` | file expiration, e.g. `3d` | never |
+| `disk` | disk type to store on | filer default |
+| `fsync` | `true` fsyncs on the volume server | false |
+| `dataCenter` | preferred data center | empty |
+| `rack` | preferred rack | empty |
+| `dataNode` | preferred volume server | empty |
+| `saveInside` | store small content inside the metadata instead of a volume | false |
+| `maxMB` | split the upload into chunks of this many MB | filer `-maxMB` |
+| `mode` | unix permission bits, e.g. `0644` | `0660` |
+| `op` | `append` appends to an existing file | overwrite |
+| `skipCheckParentDir` | `true` skips the parent-directory existence check | false |
+
+### Create a directory
+
+```bash
+curl -X POST "http://localhost:8888/dir/newdir/"
+```
+
+A POST to a path ending in `/` with no content creates the directory,
+including missing parents.
+
+### Read a file
+
+```bash
+curl "http://localhost:8888/dir/myphoto.jpg"
+```
+
+Supports `Range` requests (`Accept-Ranges: bytes`), `ETag`, and the
+`If-None-Match` / `If-Modified-Since` conditional headers. `HEAD` returns
+headers only. Entry headers stored as extended attributes are echoed back,
+minus internal `Seaweed-` and `xattr-` keys.
+
+Entry metadata instead of content:
+
+```bash
+curl "http://localhost:8888/dir/myphoto.jpg?metadata=true"
+```
+
+`metadata=true&resolveManifest=true` additionally resolves chunked-manifest
+entries into their real chunk list.
+
+### List a directory
+
+```bash
+curl -H "Accept: application/json" "http://localhost:8888/dir/?limit=10&lastFileName=a.jpg"
+```
+
+| Parameter | Description | Default |
+|-----------|-------------|---------|
+| `limit` | max entries per page | filer `-dirListLimit` |
+| `lastFileName` | resume listing after this entry name | empty |
+| `namePattern` | include only names matching the wildcard | empty |
+| `namePatternExclude` | exclude names matching the wildcard | empty |
+
+The JSON response carries `Path`, `Entries`, `Limit`, `LastFileName`,
+`ShouldDisplayLoadMore`, and `EmptyFolder`. Without the `Accept` header the
+filer renders its HTML browser.
+
+### Move and copy
+
+```bash
+curl -X POST "http://localhost:8888/dir/newname.jpg?mv.from=/dir/myphoto.jpg"
+curl -X POST "http://localhost:8888/dir/copy.jpg?cp.from=/dir/myphoto.jpg"
+```
+
+`mv.from` renames or moves the source to the request path (`204 No Content`).
+`cp.from` copies it.
+
+### Append
+
+```bash
+curl -T chunk2.bin "http://localhost:8888/dir/file.bin?op=append"
+```
+
+### Delete
+
+```bash
+curl -X DELETE "http://localhost:8888/dir/myphoto.jpg"
+curl -X DELETE "http://localhost:8888/dir/?recursive=true"
+```
+
+| Parameter | Description | Default |
+|-----------|-------------|---------|
+| `recursive` | delete a non-empty directory tree | false; when the filer runs with `filer.options.recursive_delete=true`, deletes are recursive unless `recursive=false` |
+| `ignoreRecursiveError` | keep deleting remaining entries after an error | false |
+| `skipChunkDeletion` | remove only the metadata, keep volume data | false |
+
+### Tagging
+
+Tags are carried as `Seaweed-`-prefixed request headers, not query
+parameters; `?tagging` selects the tagging handler and `?tagging=K1,K2`
+lists the keys to remove. Header names are canonicalized on write
+(`Seaweed-k1` is stored as `Seaweed-K1`), and the delete list is matched
+case-sensitively against the stored names.
+
+```bash
+curl -X PUT -H "Seaweed-k1: v1" -H "Seaweed-k2: v2" "http://localhost:8888/dir/file.jpg?tagging"
+curl -X DELETE "http://localhost:8888/dir/file.jpg?tagging=K1,K2"
+```
+
+### Read by file id
+
+```bash
+curl "http://localhost:8888/?proxyChunkId=3,01637037d6"
+```
+
+The filer proxies the chunk read to the right volume server, so only the
+filer port needs to be exposed.
+
+### Resumable uploads
+
+The filer serves the [TUS protocol](https://tus.io/) for resumable uploads
+(`POST`, `PATCH`, `HEAD` on upload URLs). It is enabled by default at
+`/.tus`; `-tusBasePath` changes the endpoint base path.
+
+### Health
+
+`GET /healthz` and `GET /readyz` return `200 OK`.
+
+## Master API (port 9333)
+
+Write-affecting endpoints are automatically proxied to the current leader, so
+any master in the quorum can serve them.
+
+### Assign a file id
+
+```bash
+curl "http://localhost:9333/dir/assign?count=1&replication=001&collection=turbo&dataCenter=dc1&ttl=3d&disk=ssd"
+{"count":1,"fid":"3,01637037d6","url":"127.0.0.1:8080","publicUrl":"localhost:8080"}
+```
+
+Upload the file content to `http://<url>/<fid>` afterwards. With `count>1`,
+use `<fid>_1`, `<fid>_2`, ... for the additional ids.
+
+| Parameter | Description | Default |
+|-----------|-------------|---------|
+| `count` | file ids to reserve | 1 |
+| `collection` | collection name | empty |
+| `dataCenter` | preferred data center | empty |
+| `rack` | preferred rack | empty |
+| `dataNode` | preferred volume server | empty |
+| `replication` | replica placement | master `-defaultReplication` |
+| `ttl` | file expiration, e.g. `3d` | never |
+| `disk` | disk type | empty |
+| `dataSize` | expected file size in bytes | 0 |
+| `preallocate` | bytes to preallocate for new volumes | master `-volumePreallocate` |
+| `writableVolumeCount` | grow this many volumes when none are writable | master default |
+| `memoryMapMaxSizeMb` | memory-mapped file size (Windows) | 0 |
+
+### Look up a volume or file id
+
+```bash
+curl "http://localhost:9333/dir/lookup?volumeId=3"
+{"locations":[{"url":"localhost:8080","publicUrl":"localhost:8080"}]}
+```
+
+| Parameter | Description | Default |
+|-----------|-------------|---------|
+| `volumeId` | volume id; a full `vid,fid` is accepted too | required |
+| `fileId` | like `volumeId`, but also returns a write JWT when security is on | empty |
+| `collection` | speeds up the lookup | empty |
+| `read` | `yes` generates a read JWT instead of a write JWT | empty |
+
+### Store a file in one call
+
+```bash
+curl -F file=@/home/chris/report.pdf "http://localhost:9333/submit?collection=turbo&replication=001"
+{"fileName":"report.pdf","fid":"3,01637037d6","fileUrl":"localhost:8080/3,01637037d6","size":43234,"eTag":"0x6c656..."}
+```
+
+`POST /submit` accepts multipart file data plus the `dir/assign` placement
+parameters (`count`, `collection`, `dataCenter`, `rack`, `replication`,
+`ttl`, `disk`), assigns a file id, uploads to the volume server, and returns
+the result.
+
+### Redirect to a file
+
+```bash
+curl -v "http://localhost:9333/3,01637037d6"
+```
+
+`GET /{fileId}` answers `308 Permanent Redirect` to a volume server holding
+the file, preserving the query string (e.g. image-resize parameters).
+
+### Cluster status
+
+```bash
+curl "http://localhost:9333/dir/status?pretty=y"   # full topology tree
+curl "http://localhost:9333/vol/status?pretty=y"   # every volume on every node
+curl "http://localhost:9333/collection/info?collection=turbo"
+curl "http://localhost:9333/collection/info?collection=turbo&detail=true"
+```
+
+`collection/info` returns aggregated `TotalSize`, `FileCount`, `UsedSize`,
+`VolumeCount`; `detail=true` splits them per volume layout.
+
+### Grow volumes
+
+```bash
+curl "http://localhost:9333/vol/grow?count=4&replication=001&collection=turbo&ttl=5d&disk=ssd&dataCenter=dc1&rack=rack1"
+{"count":4}
+```
+
+`count` is required; the placement parameters match `dir/assign`. One volume
+serves one write at a time, so pre-allocated volumes raise write concurrency.
+
+### Vacuum deleted space
+
+```bash
+curl "http://localhost:9333/vol/vacuum?garbageThreshold=0.4"
+```
+
+| Parameter | Description | Default |
+|-----------|-------------|---------|
+| `garbageThreshold` | minimum deleted-bytes ratio before a volume is compacted | master `-garbageThreshold` (0.3) |
+
+Vacuuming makes a volume read-only, copies live needles to a new volume, and
+swaps it in.
+
+### Delete a collection
+
+```bash
+curl "http://localhost:9333/col/delete?collection=benchmark"
+```
+
+Deletes all volumes of the collection, including erasure-coded shards.
+`204 No Content` on success.
+
+### Health
+
+```bash
+curl -I "http://localhost:9333/healthz"     # liveness
+curl -I "http://localhost:9333/readyz"      # readiness
+curl "http://localhost:9333/"               # web UI
+```
+
+## Volume server API (port 8080)
+
+The volume server stores file content by file id. Clients normally get the
+volume URL from `dir/assign` or `dir/lookup`.
+
+### Upload
+
+```bash
+curl -F file=@/home/chris/myphoto.jpg "http://127.0.0.1:8080/3,01637037d6"
+{"name":"myphoto.jpg","size":43234,"eTag":"0x6c656...","mime":"image/jpeg","contentMd5":"..."}
+```
+
+PUT or POST the body (or a multipart `file` part) to `/{vid},{fid}`.
+`204 No Content` is returned when the content is unchanged. `?ts=<unix>`
+sets the stored modification time.
+
+### Read
+
+```bash
+curl "http://127.0.0.1:8080/3,01637037d6"
+curl "http://127.0.0.1:8080/3,01637037d6.jpg"        # sets Content-Type from the extension
+```
+
+Supports `Range` and `HEAD`. Image files can be resized server-side:
+
+| Parameter | Description |
+|-----------|-------------|
+| `width`, `height` | resize bounds in pixels |
+| `mode` | `fit` (contain) or `fill` (cover); omitted resizes to `width`/`height` |
+| `crop_x1`, `crop_y1`, `crop_x2`, `crop_y2` | explicit crop rectangle |
+| `cm` | `false` returns the chunk-manifest blob instead of resolving it |
+| `readDeleted` | `true` reads soft-deleted needles |
+| `collection` | passed through redirects for the right volume |
+
+### Delete
+
+```bash
+curl -X DELETE "http://127.0.0.1:8080/3,01637037d6"
+{"size":43234}
+```
+
+`?ts=<unix>` sets the deletion timestamp. Replicated volumes propagate the
+delete to every replica.
+
+### Status
+
+```bash
+curl "http://localhost:8080/status?pretty=y"  # disk and volume inventory
+curl -I "http://localhost:8080/healthz"       # liveness/readiness
+```
+
+`OPTIONS` preflights answer CORS headers. When `-port.public` differs from
+`-port`, the volume server opens a separate read-only public listener on
+that port; `-publicUrl` sets the address it advertises to clients.