Pythonaccept

Pythonaccept is an open-source Python library that implements HTTP content negotiation in accordance with RFC 7231. It provides a programmatic way to parse client Accept headers (as well as related headers such as Accept-Language and Accept-Encoding) and to select the most appropriate representation from the server’s available resources. The project aims to make content negotiation predictable and framework-friendly for web services and APIs.

Its core features include parsing and normalizing q-values, support for type and language wildcards, and a configurable ranking algorithm that resolves competing representations by preference and quality. It exposes a simple API to determine the best match given a list of supported representations and a client header, and it can return both the chosen type and metadata such as the weight and the negotiated language.

Usage patterns include core library integration in custom HTTP handlers, and adapters for popular Python web frameworks such as Flask, Django, and FastAPI. The library is designed to be small, fast, and dependency-light, with optional caching for repeated negotiations and straightforward unit testing.

Pythonaccept is maintained by an open-source community and has seen regular releases since its initial release. It is intended for developers building web services that must serve multiple representations (for example HTML, JSON, or XML) while honoring client preferences. See also HTTP content negotiation, Accept header, RFC 7231.