---
title: "Join videos"
method: POST
path: "/tools/concat_videos"
---

# Join videos

`POST /tools/concat_videos`

Join two or more videos end-to-end into a single file. Async — returns 202 with a pending job; poll GET /tool_jobs/{uid} until `status` is `completed` or `failed`.

## Request body

- object
  - `video_urls` string[], required — Two or more URLs in play order
  - `transition` 'none' | 'fade' | 'dissolve' | 'wipeleft' | 'slideleft' — How each clip flows into the next. Defaults to none
  - `transition_duration` number — Only used when transition is set. Defaults to 1
  - `width` integer — Defaults to the first video's width, capped at 1920 on the long edge
  - `height` integer — Defaults to the first video's height, capped at 1080 on the short edge
  - `fps` integer — Defaults to the highest frame rate among the inputs, capped at 60
  - `metadata` string — Arbitrary metadata string stored with the tool run

## Response `202`

Tool run accepted

- object
  - `uid` string
  - `tool` 'concat_videos'
  - `status` 'pending' | 'running' | 'completed' | 'failed' — pending → running → completed / failed
  - `progress` integer — 0-100 job progress, 100 once completed
  - `inputs` object — Inputs the job was created with
  - `outputs` object
    - `video_url` string, uri
  - `metadata` string, nullable — Arbitrary metadata string round-tripped from the create request
  - `self` string, uri
  - `created_at` string, date-time
  - `completed_at` string, date-time, nullable
  - `error_message` string, nullable — Human-readable failure reason (only present on failed jobs)

## Other responses

- `402` — API quota exhausted — upgrade required
- `404` — Unknown tool
- `422` — Input validation failure

---

[API](https://skmtc.dev/bannerbear/apis/bannerbear-v5-api.md) · [All operations](https://skmtc.dev/bannerbear/apis/bannerbear-v5-api/llms.txt) · [OpenAPI document](https://skmtc-service-production.skmtc.workers.dev/v1/apis/bannerbear/bannerbear-v5-api/revisions/6aa425420a10/schema)