Face Swap Video API Reference - Magic Hour Docs

What this API does

Create the same Face Swap 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 face swap into apps, pipelines, or tools

How it works (3 steps)

1. Upload your inputs (video, image, or audio) with Generate Upload URLs and copy the file_path.
2. Send a request to create a face swap 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.

POST /v1/face-swap

Python

Python

from magic_hour import Client
from os import getenv

client = Client(token=getenv("API_TOKEN"))
res = client.v1.face_swap.generate(
    assets={
        "face_mappings": [
            {
                "new_face": "/path/to/1234.png",
                "original_face": "api-assets/id/0-0.png",
            }
        ],
        "face_swap_mode": "all-faces",
        "image_file_path": "image/id/1234.png",
        "video_file_path": "/path/to/1234.mp4",
        "video_source": "file",
    },
    end_seconds=15.0,
    start_seconds=0.0,
    name="Face Swap video",
    style={"version": "default"},
    wait_for_completion=True,
    download_outputs=True,
    download_directory="."
)

200

{
  "id": "cuid-example",
  "credits_charged": 450
}

Authorizations

Authorization · string · header · required

Bearer authentication header of the form Bearer <api_key>, where <api_key> is your API key. To get your API key, go to Developer Hub and click "Create new API Key".

Body

application/json

Body

start_seconds · number<float> · required

Start time of your clip (seconds). Must be ≥ 0.

Required range: x >= 0

Example:

0

end_seconds · number<float> · required

End time of your clip (seconds). Must be greater than start_seconds.

Required range: x >= 0.1

Example:

15

assets · object · required

Provide the assets for face swap. For video, The video_source field determines whether video_file_path or youtube_url field is used

Show child attributes

name · string · default: Face Swap - dateTime

Give your video a custom name for easy identification.

Example:

"My Face Swap video"

style · object

Style of the face swap video.

Show child attributes

Example:

{ "version": "default" }

Response

200

application/json

Success

Success

id · string · required

Unique ID of the video. Use it with the Get video Project API to fetch status and downloads.

Example:

"cuid-example"

credits_charged · integer · required

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