AnimateCaptionsTry it free
Caption API

Caption API for animated, word-by-word video captions.

Automate TikTok-, Reels- and Shorts-style captions from your own code: one request in, a captioned MP4 out.

Last updated

Try it free
Quick answer

The AnimateCaptions caption API is a REST API that adds animated, word-by-word captions to a video. You POST a job to /api/v1/jobs with a video URL (or upload the file to a presigned URL), choose one of 37 caption styles and a position such as bottom or exact x/y coordinates, poll the job until it completes, and download an MP4 with the captions burned in. Authentication is a free personal API key from animatecaptions.com/developers.

Key takeaways

  • One POST creates a job; the video is transcribed with word-level timing and rendered with your chosen style.
  • 37 animated presets, including Hormozi-style and MrBeast-style captions, plus colour, font size and animation overrides.
  • Position captions with top, middle or bottom, or exact x/y percentages of the frame.
  • API jobs show up in your project list, so a person can still fine-tune them in the editor.

What the caption API does

Each job runs the same pipeline as the web editor: speech is transcribed automatically (the language is detected automatically), words are grouped into short caption chunks, and the selected animated style is rendered frame by frame into the video. The result is an MP4 with open captions that look the same on every platform.

Styles, position and customization

Pass style with any id from GET /api/v1/styles (for example beast, punch, neon or nova). Pass position as top, middle or bottom, or as {"x": 50, "y": 80}. The customization object accepts font_size, font_family, primary_color, highlight_color, active_word_color, uppercase, stroke and background colours, animation (pop, fade, zoom, slide-up, slide-down, none) and an AI keyword highlighter.

Two ways to send the video

For videos already online, send source_url and the job is queued immediately. For local files, send filename and file_size: the response contains a presigned upload URL, you PUT the bytes, then call POST /api/v1/jobs/{id}/start. Either way, nothing has to be streamed through your own servers.

Built for automation and batch workflows

Typical uses are content pipelines that caption every clip before scheduling, SaaS products that offer captions to their own users, and agencies captioning many client videos with a consistent saved theme (theme_id). Errors are returned as JSON with a code and message, and limits follow your plan.

Caption API vs captioning by hand

FeatureCaption APIManual editor
Who triggers itYour code or an AI agentA person in the browser
Per-video effortOne requestUpload, review, style, export
Consistent stylingSame style/theme on every jobChosen per video
Word-level fixesOptional, in the editor afterwardsBuilt into the workflow
Step by step

From API key to captioned MP4.

  1. 1

    Create a free API key

    Sign in at animatecaptions.com/developers and create a personal API key (ac_live_…). Send it as an Authorization: Bearer header on every request.

  2. 2

    Create a caption job

    POST /api/v1/jobs with a source_url (a public direct link to an MP4 or MOV) or with filename + file_size to receive a presigned upload URL. Add style, position and optional customization.

  3. 3

    Poll the job status

    GET /api/v1/jobs/{id} moves through queued, transcribing and rendering to completed. A short clip usually finishes in one to two minutes.

  4. 4

    Download the captioned MP4

    Completed jobs include a one-hour download_url, or call GET /api/v1/jobs/{id}/download. The job also appears in your project list for manual tweaks.

Editor walkthrough

Edit and preview before you export.

Correct words, customize the style, reposition individual lines, and preview the burned-in result.

Related guides

Continue with a specific workflow.

API & MCP docsSubtitle APIMCP server for video captions
Common questions

Frequently asked questions.

Is there an API for animated captions?

Yes. AnimateCaptions provides a REST API at https://animatecaptions.com/api/v1 that creates caption jobs, reports their status and returns a captioned MP4.

Can I choose where the captions appear?

Yes. Set position to top, middle or bottom, or to exact x/y percentages of the frame for the centre of the caption block.

How much does the API cost?

API keys are free. Jobs count against your plan's monthly uploads: the free plan includes 3 videos per month up to 2 minutes with a watermark; paid plans remove the watermark and raise the limits.

Which video formats are supported?

MP4 and MOV, up to 500 MB on the free plan and 2 GB on paid plans, sent as a public direct link or uploaded to a presigned URL.

Where are the full API docs?

At animatecaptions.com/developers, which also lists every caption style (GET /api/v1/styles needs no key) and the MCP setup for AI agents.

Add accurate animated captions to your next clip.

Upload, correct, style, position, and export in one browser workflow.

Try it free