CaptionCraft API
v1

Your video.
Captions, ready to share.

Send a video URL and choose a style. Get back a captioned MP4, an SRT file, and a word-timed transcript.

OpenAPI specificationExplore presets
Classic

Crisp white captions with a dark outline.

Highlight

Bold captions that follow each spoken word.

Karaoke

Rounded type with a progressive color fill.

One request to get started

Use your CaptionCraft API key. Each accepted submission creates a new job.

curl "$CAPTIONCRAFT_API_URL/v1/subtitles" \
  -H "Authorization: Bearer $CAPTIONCRAFT_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"video_url":"https://example.com/video.mp4",
       "preset":"highlight"}'

The API returns 202 Accepted and a status_url. Poll it every five seconds with the same authorization header. A completed job includes MP4, SRT, and transcript download links.

Predictable usage

Prepaid seconds
Submission requires a positive prepaid balance. After inspecting the video, the API reserves its actual duration rounded up before transcription. Insufficient credit fails the job without a charge. Successful jobs charge the actual duration rounded up to a whole second. Failed or canceled jobs release their reservation.
Supported media
Direct HTTPS URLs to MP4, MOV, or WebM; up to 500 MiB, 10 minutes, and 1080p in landscape or portrait. Redirects are rejected.
Private results
Job status requires your API key. Result links grant access to the file to anyone holding the link. Output files are available for 24 hours and are then deleted.

Endpoints

GET  /v1/presets
POST /v1/subtitles
GET  /v1/jobs/{id}
POST /v1/jobs/{id}/cancel
GET  /v1/usage