bootstrap-elixir-openapi

To generate an Elixir API client from an OpenAPI spec, you bootstrap a new library using compile-time extraction of paths and components. This produces typed schema structs, a Req-based HTTP client, endpoint functions, and unit tests directly from the 3.x specification.

OpenAPI schema generation handles nested $ref and composition by creating typed structs with recursive from_map/1 conversions. It correctly processes anyOf, allOf, and array-of-ref cases to ensure accurate data parsing for complex API schemas in Elixir.

Yes, you can use Req and Mimic for Elixir OpenAPI client generation. The generated library uses Req for HTTP requests and Mimic to mock those requests, validating behavior and error handling in spec-driven unit and integration tests.

The best way to keep an Elixir API client updated when an OpenAPI spec changes is using @external_resource-based recompilation. This provides compile-time determinism and allows repeatable regeneration of your scaffolding whenever the specification is modified.

Generating an Elixir client from OpenAPI supports custom authentication headers by requiring correct auth header behavior during the bootstrapping process. You provide the API name, package name, module name, spec path, and auth style to configure it.

You should not use automated code generation for your Elixir API wrapper if your project lacks a valid OpenAPI 3.x specification or if you need runtime code generation instead of the compile-time determinism and static scaffolding this approach provides.