Change the caption highlight colour without changing the style

How do you change the highlighted word colour in burned-in captions without redesigning them? Send a design object with colors.active. It merges over the style you named, so one key changes one thing and everything else stays as the style defined it.

Transcription keeps getting cheaper: Microsoft's streaming model (read 2026-10-04) is priced at $0.54 per hour of audio through year-end. When timing is a commodity, the part viewers notice is the look, and for a brand that starts with the accent colour.

The request

Required for a standalone caption job is video_url, a public HTTPS URL. This example burns the black-outline style with a cyan spoken word, as in the video captions guide.

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" } }
  }'

What you can and cannot set

A style is a set of design tokens and design overrides them for one request. Every field is optional.

Rules that save a retry

Colours are hex, rgb()/rgba() or transparent; other CSS syntax is rejected rather than drawn into the render. Numbers outside their documented range return 400, so a bad look fails at request time instead of rendering wrong and billing.

design is not supported on punch or tiktok-green; those render on a path that reads none of these tokens.

An omitted style drops the gold spoken-word tint both defaults were authored with, so a defaulted render keeps the fill colour on the spoken word. Naming black-outline or slam keeps that style's gold tint, and design.colors.active sets the colour either way.

A standalone caption job reserves $0.20 for videos up to 60 seconds under the current fixed estimate; confirm live pricing in GET /v1/catalog.