Customize caption colors via API: not on punch or tiktok-green

You cannot customize caption colors on tiktok-green through the API. The design object overrides a style's colours, typography, placement, phrasing and motion for one request, but the docs say it is not supported on punch or tiktok-green. Pick another style, such as black-outline, if you need overrides.

Descript rebuilt its caption properties panel on 2026-09-17. Sume's per-request switch is the design field, with limits listed in Video captions.

Which styles take a design object?

A style is a set of design tokens and design merges over them, so one key changes one thing. Every field is optional.

What does a working override look like?

The docs example sets only the spoken-word colour on black-outline; all other tokens stay as the style defines them.

{
  "video_url": "https://example.com/clean.mp4",
  "style": "black-outline",
  "design": { "colors": { "active": "#22D3EE" } }
}

What colour formats and ranges are valid?

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

Why do punch and tiktok-green ignore design?

The docs say they still render on a path that reads none of these tokens. For the full list of what you can tune elsewhere, read customize burned-in captions.