Feature Request: Built-in OpenAPI/Swagger Documentation Generation

[youssefmzouri]

I'd like to suggest adding native OpenAPI documentation generation to mojo.js, similar to what FastAPI or NestJS provide.

Currently, we have to maintain API documentation separately from our route definitions, which leads to outdated docs, code duplication, and many teams just skipping documentation altogether. Other frameworks solve this by generating OpenAPI specs automatically from route definitions.

app.get('/users/:id', {
  summary: 'Get user by ID',
  parameters: { id: { type: 'string' } },
  responses: { 200: { description: 'User found' } }
}, async ctx => {
  // handler logic
});

// Auto-generate spec and serve docs
app.generateOpenAPI('/docs');

This would include automatic OpenAPI 3.0 generation, built-in Swagger UI, and optional request/response validation. The feature should be opt-in to maintain backward compatibility and have minimal runtime overhead.

Question for the community:

• Which implementation approach would work best for mojo.js?
• Have you implemented a solution to resolve this use case? How? I'd love to hear from you.

I'd be happy to help develop this if there's interest from maintainers and the community!

[kraih]

Traditionally the mojo frameworks always left OpenAPI to plugins.

[youssefmzouri]

Nice! I thought I might try to start this development myself....

• Is there any plugin development documentation or patterns I should follow?
• Any advice ? I'm thinking about how to best integrate with the routing system to extract endpoint information automatically.

Any guidance would be really helpful before I start working on this!