---
title: "Comment on a thread"
description: "Write to the team, not the sender."
url: "https://openemail.uk/docs/api/team/comments/create"
area: "API"
category: "Mailbox"
---

# Comment on a thread

Write to the team, not the sender.

`POST /threads/{id}/comments`

## POST /threads/{id}/comments

Write to the team, not the sender.

## Example

Needs `threads:write`. `body` is up to 10,000 characters, and `mentions` holds up to 20 user ids from the `team` of the thread. Each person mentioned is emailed. Answers 201 with the comment.

**curl**

```
curl -X POST "$OE/threads/thr_7c1e4a90/comments" -H "$AUTH" -H "Content-Type: application/json" \
  -d '{ "body": "Grace, can you take this one? They want the invoice sent again.", "mentions": ["usr_2f9c1d"] }'
```

**Response**

```
{
  "object": "thread_comment",
  "id": "tcm_5e0b9c7a2d4f4e1b8a6c3d2e1f0a9b8c",
  "threadId": "thr_7c1e4a90",
  "author": {
    "object": "team_member",
    "id": "usr_8a41be",
    "name": "Ada Lovelace",
    "email": "ada@example.com"
  },
  "body": "Grace, can you take this one? They want the invoice sent again.",
  "mentions": [{
      "object": "team_member",
      "id": "usr_2f9c1d",
      "name": "Grace Hopper",
      "email": "grace@example.com"
    }],
  "createdAt": "2026-10-14T09:15:02.000Z",
  "editedAt": null
}
```

> Mentioning somebody who cannot see the thread is a 422 `invalid_parameter` on `mentions`, and nothing is saved. Sending the same request twice adds two comments.

> A key acts for the workspace owner. A key limited to particular addresses or domains reaches only the threads that arrived at them, and any other thread is a 404.

## Reference

- [`POST /threads/{id}/comments`](https://openemail.uk/docs/api/reference/team-inbox#post-threads-id-comments): full reference