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/v1/emphasize is the only ACAAS endpoint that thinks for itself. Instead of uppercasing every character, a small model reads your text and chooses which words most deserve emphasis. Chosen words are wrapped in markdown bold (**word**) and returned alongside the originals. Because a model is in the loop, behavior is non-deterministic. Two identical requests may produce different results, and the model may change between versions. Treat this endpoint as a creative collaborator, not a pure function.
Do not write code that depends on a specific emphasis output. If you need deterministic behavior, use /v1/shout or /v1/scream.

Make a request

The body takes a text field and an optional emphasis_ratio. Authentication is the standard X-API-Key header.

Tune emphasis_ratio

emphasis_ratio controls roughly what fraction of words the model selects. Values above 0 and up to 1.0 are accepted. The default is 0.3. The ratio is a guideline, not a guarantee. The model rounds to whole words and may pick fewer than requested for very short input.

Response shape

  • original — the text you sent in.
  • result — the text with emphasized words wrapped in markdown bold.
  • emphasized_words — the exact words the model chose, in order of appearance.
  • model — name and version of the emphasis model. Pin against this if you need to detect upstream changes.
  • experimental — always true. A reminder that behavior may shift.

When to use it

Reach for /v1/emphasize when:
  • You want highlights for human readers — release notes, headings, captions.
  • The exact wording matters less than the rhythm of emphasis.
  • You can render markdown bold downstream.
Avoid it when:
  • You need byte-stable output across calls.
  • You are formatting data for machines, not people.
  • Markdown is not part of the rendering pipeline — bold asterisks will appear as literal characters.

Errors

Validation errors return HTTP 422 with a detail array. The most common causes are empty text or an emphasis_ratio outside the allowed range.
422 example
For the standard 401, 413, and 429 cases, see Quickstart → Handle errors.

Next steps

Full API reference

Complete request and response schema for /v1/emphasize.

Back to the basics

The deterministic, predictable cousin: /v1/shout.