---
title: "Reply to a comment thread"
method: POST
path: "/projects/{projectId}/comment-threads/{threadId}/replies"
tags: ["Comments"]
---

# Reply to a comment thread

`POST /projects/{projectId}/comment-threads/{threadId}/replies`

## Request

- Base URL: `https://app.flora.ai/api/v1`
- URL: `https://app.flora.ai/api/v1/projects/{projectId}/comment-threads/{threadId}/replies`
- Auth: HTTP bearer

Posts a reply on an open comment thread. Resolved threads return `input_validation_error`. Missing threads and inaccessible projects return 404. Mutating public API requests support an optional Idempotency-Key header for client retries; duplicate keys within two hours return idempotency_duplicate.

## Path parameters

- `projectId` string, required: Project identifier
- `threadId` string, required: Comment thread identifier

## Request body

- object
  - `body` string, required: Plain-text comment body
  - `author` 'user': Who the comment is attributed to. `user` posts as the credential's user. Defaults to `user`.

## Response `201`

Reply posted.

- object
  - `comment_id` string, required: Comment identifier
  - `body` string, required: Plain-text comment body
  - `author` object, required
    - `type` 'user' | 'anonymous' | 'flora', required: Author kind
    - `name` string, required: Display name
    - `profile_image_url` string, uri: Author profile image URL
  - `created_at` number, required: When the comment was created, as a Unix timestamp in milliseconds

## Other responses

- `400`: 400
- `401`: 401
- `402`: 402
- `403`: 403
- `404`: 404
- `409`: 409
- `429`: 429
- `500`: 500
- `503`: 503

## Changes

- **2026-10-28** `a8351619f225`: 9 warning
  - added the new `not_configured` enum value to the `error/code` response property for the response status `400`
  - added the new `not_configured` enum value to the `error/code` response property for the response status `401`
  - added the new `not_configured` enum value to the `error/code` response property for the response status `402`
  - added the new `not_configured` enum value to the `error/code` response property for the response status `403`
  - …5 more
- **2026-10-16** `e54130373b10`: 1 info
  - endpoint added

[Operation history](https://skmtc.dev/florafauna-ai/apis/flora-ai-api/changes/projects/:projectId/comment-threads/:threadId/replies/post.md)

---

[API](https://skmtc.dev/florafauna-ai/apis/flora-ai-api.md) - [All operations](https://skmtc.dev/florafauna-ai/apis/flora-ai-api/llms.txt) - [OpenAPI document](https://skmtc.dev/florafauna-ai/apis/flora-ai-api/revisions/87cfe2c4ac29?raw)