> ## Documentation Index > Fetch the complete documentation index at: https://docs.magichour.ai/llms.txt > Use this file to discover all available pages before exploring further. # Character Replace API Reference - Magic Hour Docs > **What this API does** Create the same Character Replace you can make in the browser, but programmatically, so you can automate it, run it at scale, or connect it to your own app or workflow. **Good for** - Automation and batch processing - Adding character replace into apps, pipelines, or tools **How it works (3 steps)** 1) Upload your inputs (video, image, or audio) with [Generate Upload URLs](https://docs.magichour.ai/api-reference/files/generate-asset-upload-urls) and copy the `file_path`. 2) Send a request to create a character replace job with the basic fields. 3) Check the job status until it's `complete`, then download the result from `downloads`. **Key options** - Inputs: usually a file, sometimes a YouTube link, depending on project type - Resolution: free users are limited to 576px; higher plans unlock HD and larger sizes - Extra fields: e.g. `face_swap_mode`, `start_seconds`/`end_seconds`, or a text prompt **Cost** Credits are only charged for the frames that actually render. You'll see an estimate when the job is queued, and the final total after it's done. For detailed examples, see the [product page](https://magichour.ai/products/character-replace). ## OpenAPI ````yaml post /v1/character-replace openapi: 3.0.2 info: title: Magic Hour API version: beta description: > Magic Hour provides an API (beta) that can be integrated into your own application to generate videos and images using AI. Webhook documentation can be found [here](https://magichour.ai/docs/webhook). If you have any questions, please reach out to us via [discord](https://discord.gg/JX5rgsZaJp). # Authentication Every request requires an API key. To get started, first generate your API key [here](https://magichour.ai/settings/developer). Then, add the `Authorization` header to the request. | Key | Value | |-|-| | Authorization | Bearer mhk_live_apikey | > **Warning**: any API call that renders a video will utilize credits in your account. termsOfService: https://magichour.ai/terms-of-service servers: - url: https://api.magichour.ai security: [] tags: - name: Files description: API related to uploading assets used for video generation - name: Image Projects description: API related to image projects - name: Video Projects description: API related to video projects - name: Audio Projects description: API related to audio projects paths: /v1/character-replace: post: tags: - Video Projects summary: Character Replace description: >- **What this API does** Create the same Character Replace you can make in the browser, but programmatically, so you can automate it, run it at scale, or connect it to your own app or workflow. **Good for** - Automation and batch processing - Adding character replace into apps, pipelines, or tools **How it works (3 steps)** 1) Upload your inputs (video, image, or audio) with [Generate Upload URLs](https://docs.magichour.ai/api-reference/files/generate-asset-upload-urls) and copy the `file_path`. 2) Send a request to create a character replace job with the basic fields. 3) Check the job status until it's `complete`, then download the result from `downloads`. **Key options** - Inputs: usually a file, sometimes a YouTube link, depending on project type - Resolution: free users are limited to 576px; higher plans unlock HD and larger sizes - Extra fields: e.g. `face_swap_mode`, `start_seconds`/`end_seconds`, or a text prompt **Cost** Credits are only charged for the frames that actually render. You'll see an estimate when the job is queued, and the final total after it's done. For detailed examples, see the [product page](https://magichour.ai/products/character-replace). operationId: characterReplace.createVideo parameters: [] requestBody: required: true description: Body content: application/json: schema: type: object properties: name: type: string description: Give your video a custom name for easy identification. example: My Character Replace video default: Character Replace - dateTime start_seconds: default: 0 type: number minimum: 0 description: Start time of your clip (seconds). Must be ≥ 0. format: float example: 0 end_seconds: type: number minimum: 0.1 description: >- End time of your clip (seconds). Must be greater than start_seconds. format: float example: 15 resolution: type: string enum: - 480p - 720p description: >- Output video resolution. Defaults to 480p, the lowest resolution available on your plan. example: 720p assets: type: object properties: video_file_path: type: string minLength: 1 description: > Source video containing the subject to replace or animate. This value is either - a direct URL to the video file - `file_path` field from the response of the [upload urls API](https://docs.magichour.ai/api-reference/files/generate-asset-upload-urls). See the [file upload guide](https://docs.magichour.ai/api-reference/files/generate-asset-upload-urls#input-file) for details. example: api-assets/id/1234.mp4 image_file_path: type: string minLength: 1 description: > Reference character image used as the replacement or animation target. This value is either - a direct URL to the video file - `file_path` field from the response of the [upload urls API](https://docs.magichour.ai/api-reference/files/generate-asset-upload-urls). See the [file upload guide](https://docs.magichour.ai/api-reference/files/generate-asset-upload-urls#input-file) for details. example: api-assets/id/5678.png required: - video_file_path - image_file_path description: Source video and reference character image for the job. style: type: object properties: mode: type: string enum: - replace - animate description: >- Processing mode. `replace` swaps the detected subject with your reference character. `animate` transfers motion from the video onto your character image. example: replace selection_mode: type: string enum: - auto - point description: >- How to locate the subject in the source video. `auto` detects a person automatically. `point` uses your `points` to mark the subject. Defaults to `auto`. example: auto points: type: array items: type: object properties: position_x: type: integer minimum: 0 description: >- Horizontal pixel coordinate in the source video frame at `time_seconds`, measured from the left edge. example: 320 position_y: type: integer minimum: 0 description: >- Vertical pixel coordinate in the source video frame at `time_seconds`, measured from the top edge. example: 180 time_seconds: type: number minimum: 0 description: >- Timestamp on the source video timeline in seconds. Uses the same clock as `start_seconds` and `end_seconds`. format: float example: 2.5 required: - position_x - position_y - time_seconds description: >- On-frame markers for manual subject selection. Required when `selection_mode` is `point`. Ignored when `selection_mode` is `auto` or omitted. description: >- Optional style controls for replace vs animate mode and subject selection. required: - end_seconds - assets responses: '200': description: Success content: application/json: schema: type: object properties: id: type: string example: cuid-example description: >- Unique ID of the video. Use it with the [Get video Project API](https://docs.magichour.ai/api-reference/video-projects/get-video-details) to fetch status and downloads. credits_charged: type: integer description: >- The amount of credits deducted from your account to generate the video. If the status is not 'complete', this value is an estimate and may be adjusted upon completion based on the actual FPS of the output video. If video generation fails, credits will be refunded, and this field will be updated to include the refund. example: 450 required: - id - estimated_frame_cost - credits_charged description: Success '400': description: Invalid Request content: application/json: schema: type: object properties: message: type: string required: - message description: The request is invalid example: message: Missing request body '401': description: Unauthorized content: application/json: schema: type: object properties: message: type: string enum: - Unauthorized required: - message description: The request is not properly authenticated example: message: Unauthorized '402': description: Payment Required content: application/json: schema: type: object properties: message: type: string required: - message description: The request requires payment example: message: Payment required '404': description: Not Found content: application/json: schema: type: object properties: message: type: string enum: - Not Found required: - message description: Requested resource is not found example: message: Not Found '422': description: Unprocessable Entity content: application/json: schema: type: object properties: message: type: string example: Unable to create video required: - message description: Unprocessable Entity security: - bearerAuth: [] components: securitySchemes: bearerAuth: type: http scheme: bearer description: >- Bearer authentication header of the form `Bearer `, where `` is your API key. To get your API key, go to [Developer Hub](https://magichour.ai/developer?tab=api-keys) and click "Create new API Key". ````