chanfana/llms.txt

OpenAPI 3 and 3.1 schema generator and validator for Hono, itty-router and more!

# Chanfana

> OpenAPI 3 and 3.1 schema generator and validator for Hono, itty-router, and Cloudflare Workers.

Chanfana automatically generates OpenAPI specs from Zod v4 schemas, validates requests, and provides auto CRUD endpoints with built-in D1 database support.

## Quick Example

```typescript
import { Hono } from 'hono';
import { fromHono, OpenAPIRoute, contentJson } from 'chanfana';
import { z } from 'zod';

class GetUser extends OpenAPIRoute {
  schema = {
    request: {
      params: z.object({ id: z.number() }),
    },
    responses: {
      "200": {
        description: "User found",
        ...contentJson(z.object({
          success: z.boolean(),
          result: z.object({ id: z.number(), name: z.string() }),
        })),
      },
    },
  };

  async handle(c) {
    const { params } = await this.getValidatedData<typeof this.schema>();
    return { success: true, result: { id: params.id, name: "Alice" } };
  }
}

const app = new Hono();
const openapi = fromHono(app);
openapi.get('/users/:id', GetUser);
export default app;
```

## Key Concepts

- **Zod v4 syntax**: Use `z.email()`, `z.uuid()`, `z.iso.datetime()` (not `z.string().email()`)
- **Router adapters**: `fromHono(app)` for Hono, `fromIttyRouter(router)` for itty-router
- **Auto CRUD**: `CreateEndpoint`, `ReadEndpoint`, `UpdateEndpoint`, `DeleteEndpoint`, `ListEndpoint`
- **D1 CRUD**: `D1CreateEndpoint`, `D1ReadEndpoint`, `D1UpdateEndpoint`, `D1DeleteEndpoint`, `D1ListEndpoint`
- **Exceptions**: `NotFoundException`, `InputValidationException`, `UnauthorizedException`, etc.
- **Content helper**: `contentJson(zodSchema)` wraps schemas for `application/json` content
- **Validated data**: `await this.getValidatedData<typeof this.schema>()` returns typed `{ params, query, body, headers }`
- **Raw data**: `await this.getUnvalidatedData()` returns data before Zod defaults are applied

## Package Contents for AI

This package includes source code and documentation to help AI tools understand the library:

- `AGENTS.md` — Comprehensive development guide: architecture, patterns, migration notes, testing
- `skills/write-endpoints/SKILL.md` — Step-by-step coding skill for building endpoints with chanfana
- `docs/` — Full user documentation (VitePress markdown)
- `src/` — TypeScript source code for all modules

## Documentation

- Homepage: https://chanfana.pages.dev
- GitHub: https://github.com/cloudflare/chanfana
- Getting Started: docs/getting-started.md
- Defining Endpoints: docs/endpoints/defining-endpoints.md
- Auto CRUD Endpoints: docs/endpoints/auto/base.md
- D1 Database Endpoints: docs/endpoints/auto/d1.md
- Error Handling: docs/error-handling.md
- Migration Guide: docs/migration-to-chanfana-3.md