API Routing

This project uses Hono as the backend framework. You can add or edit API routes in apps/api/src/index.ts.

In order to get hono client types to be passed across packages at build time, there is a new build:types command in api package.

Basic Route Structure

import { Hono } from 'hono';
import { cors } from 'hono/cors';

const app = new Hono();

// Apply middleware
app.use('*', cors({
  origin: process.env.CORS_ALLOWLISTED_ORIGINS?.split(',') || [],
}));

// Define routes
app.get('/api/health', (c) => c.json({ status: 'ok' }));

// Group routes
const users = new Hono();
users.get('/', (c) => c.json({ users: [] }));
users.post('/', (c) => c.json({ message: 'User created' }));

app.route('/api/users', users);

Middleware

Hono provides a powerful middleware system. Here are some common middleware patterns:

// Authentication middleware
const auth = async (c, next) => {
  const token = c.req.header('Authorization');
  if (!token) {
    return c.json({ error: 'Unauthorized' }, 401);
  }
  // Verify token
  await next();
};

// Apply to specific routes
app.use('/api/protected/*', auth);

// Apply to all routes
app.use('*', async (c, next) => {
  console.log(`${c.req.method} ${c.req.url}`);
  await next();
});

Request Validation

Hono works well with Zod for request validation:

import { z } from 'zod';
import { zValidator } from '@hono/zod-validator';

const userSchema = z.object({
  name: z.string().min(3),
  email: z.string().email(),
});

app.post('/api/users', zValidator('json', userSchema), (c) => {
  const data = c.req.valid('json');
  // Process validated data
  return c.json({ message: 'User created', data });
});

Error Handling

// Global error handler
app.onError((err, c) => {
  console.error(`${err}`);
  return c.json({ error: 'Internal Server Error' }, 500);
});

// Not found handler
app.notFound((c) => {
  return c.json({ error: 'Not Found' }, 404);
});

Type Generation

To generate types for your API routes:

1. Run bun run build:types in the API package
2. Import the generated types in your frontend code:

import type { Api } from 'api';

Best Practices

• Group related routes using Hono's routing system
• Use middleware for cross-cutting concerns
• Validate all incoming requests with Zod
• Implement proper error handling
• Keep route handlers focused and delegate business logic to services
• Use TypeScript for type safety across the stack