Hono
Overview
Hono is a small, ultrafast web framework built on Web Standards that runs on any JavaScript runtime including Cloudflare Workers, Bun, Deno, Node.js, Vercel, and AWS Lambda. Application code is portable across runtimes; only the entry point and adapter differ per platform.
When to use: Edge-first APIs, Cloudflare Workers services, multi-runtime applications, lightweight REST/RPC servers, middleware-heavy request pipelines, type-safe client-server communication.
When NOT to use: Full-stack SSR frameworks (use Next.js/Remix), heavy ORM-driven monoliths where Express ecosystem maturity matters, applications that need deep Node.js-only APIs without Web Standard equivalents.
Quick Reference
| Pattern | API | Key Points |
|---|---|---|
| Basic routing | app.get('/path', handler) | Supports get, post, put, delete, patch, all |
| Path parameters | app.get('/user/:id', handler) | Access via c.req.param('id') |
| Regex constraints | app.get('/post/:id{[0-9]+}', handler) | Inline regex in path parameter |
| Wildcard | app.get('/files/*', handler) | Matches any sub-path |
| Route grouping | app.route('/api', subApp) | Mount sub-applications |
| Middleware | app.use(middleware()) | Executes in registration order |
| Path middleware | app.use('/auth/*', jwt(...)) | Scope middleware to paths |
| JSON response | c.json({key: 'value'}) | Sets Content-Type automatically |
| Text response | c.text('hello') | Returns plain text |
| HTML response | c.html('<h1>Hi</h1>') | Returns HTML content |
| Status + header | c.status(201), c.header('X-Key', 'val') | Chain before response |
| Redirect | c.redirect('/new-path', 301) | Default status is 302 |
| Request body | c.req.json(), c.req.parseBody() | JSON or form data parsing |
| Query params | c.req.query('page') | Single query parameter |
| Context variables | c.set('user', data) / c.get('user') | Type-safe middleware data passing |
| Zod validation | zValidator('json', schema) | @hono/zod-validator package |
| RPC client | hc<AppType>(url) | End-to-end type-safe API calls |
| Error handler | app.onError((err, c) =>...) | Global error handling |
| Not found | app.notFound((c) =>...) | Custom 404 handler |
| Environment | c.env.BINDING_KEY | Access runtime bindings/env vars |
| Adapter helper | env(c) from hono/adapter | Unified env access across runtimes |
| WebSocket | upgradeWebSocket() from runtime adapter | WebSocket helper with RPC support |
| Test client | testClient(app) from hono/testing | Type-safe testing without HTTP server |
| JSX streaming | jsxRenderer({stream: true}) | SSR streaming with Suspense support |
Common Mistakes
| Mistake | Correct Pattern |
|---|---|
| Registering middleware after handlers | Register middleware before the handlers it should apply to |
Using app.route() without chaining for RPC types | Chain route methods (app.route('/a', a).route('/b', b)) and export typeof routes |
Forgetting export default app for edge runtimes | Cloudflare Workers, Bun, and Deno require the default export |
Using compress() on Cloudflare Workers or Deno Deploy | These platforms compress automatically; skip the middleware |
| Mixing Hono and middleware versions in Deno | Pin all hono imports to the same version to avoid type mismatches |
Wrapping next() in try/catch inside middleware | Hono catches thrown errors and routes to app.onError(); next() never throws |
Defining routes with app.get() but exporting typeof app for RPC | Export the type of the chained route variable, not the app instance |
Using new Hono() without generics for typed context | Pass Hono<{Variables: MyVars}> to enable typed c.get()/c.set() |
Returning c.json() without status for created resources | Pass status as second argument: c.json(data, 201) |
Not using createMiddleware() for reusable middleware | Import from hono/factory to preserve type inference when extracting middleware |
Delegation
If thezodortypescript-patternsskill is available, delegate schema and type-level tasks to it. Otherwise, recommend:npx skills add oakoss/agent-skills --skill typescript-patternsIf a Cloudflare Workers skill is available, delegate platform-specific configuration to it.
References
- Route definitions, path params, groups, and method handlers
- Built-in and custom middleware patterns
- Context object, request parsing, and response helpers
- Zod validator middleware and request validation
- RPC client and end-to-end type safety
- Runtime adapters for Cloudflare, Bun, Node.js, Deno, and more
- Testing with testClient, WebSocket helper, and JSX streaming