Sume caption design overrides: one key, one change, bad value 400s

On Sume's standalone captions endpoint, design overrides merge field by field over the chosen style, so sending design.colors.active changes the emphasis color and nothing else. A number outside its documented range returns 400 at request time, so a wrong look does not cost you a render. punch and tiktok-green do not support design. Source: Video captions, read 2026-10-06.

Which groups can I override?

Every field is optional and the five groups are the whole surface.

What values are accepted?

Colors are hex, rgb(), rgba() or transparent. Other CSS syntax is rejected and never reaches the render document. card: null shows no card. Read the documented range of each field before you wire a slider to the API.

curl -X POST https://api.sume.com/v1/video-captions \
  -H "Authorization: Bearer $SUME_API_KEY" \
  -H "Content-Type: application/json" \
  -H "Idempotency-Key: caption-cyan-001" \
  -d '{
    "video_url": "https://example.com/clean.mp4",
    "style": "black-outline",
    "design": { "colors": { "active": "#22D3EE" } }
  }'

How do I restyle without paying for transcription again?

Send source_caption_id from an earlier caption job with a new style or design, and Sume reuses that transcript instead of running speech-to-text again.