Content Negotiation API
HTTP content negotiation as an API. The parse endpoint reads an Accept, Accept-Language, Accept-Encoding or Accept-Charset header — with quality (q) values and parameters — into a clean list ranked by the client's preference. The negotiate endpoint takes that header plus the list of values your server can actually serve and returns the single best match, along with the full ranked result and the entry that matched each candidate. It applies the correct rules for each kind: media-type type and subtype wildcards (text/*, */*), RFC 4647 language-range matching (a request for en matches your en-US, and en-US falls back to en), and exact matching with a * wildcard for encodings and charsets — and a q=0 entry correctly rejects a value. Everything runs locally and deterministically, so it is instant and private. Ideal for i18n middleware and locale selection, API versioning by media type, response-format and compression selection, CDNs, proxies and edge functions. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 3 endpoints. This negotiates HTTP headers; to validate or decompose a single BCP-47 language tag use a BCP-47 API.
api.oanor.com/negotiate-api
