About dart_express#

dart_express is a web framework for Dart inspired by Express.js, designed to make building HTTP servers simple, intuitive, and productive.

Philosophy#

Simplicity First#

dart_express follows the Express.js philosophy: provide a minimal, flexible framework that doesn't get in your way.

final app = DartExpress();
app.get('/', (req, res) => res.text('Simple!'));
await app.listen(3000);

Middleware-Centric#

Everything is a middleware. This makes the framework incredibly composable:

// Logging
app.use((req, res, next) async {
  print('${req.method} ${req.uri.path}');
  await next();
});

// CORS
app.use(app.cors());

// Routes
app.get('/api', handler);

Type-Safe#

Built on Dart, you get compile-time type safety:

app.post('/api/user', (req, res) async {
  final body = await req.body; // Map<String, dynamic>
  final name = body['name'] as String; // Type-checked
  res.json({'created': name});
});

Architecture#

Request Pipeline#

Request →  Middleware 1 →  Middleware 2 →  Route Handler →  Response
              ↓                ↓                ↓
           next()          next()           res.json()

Every request flows through:

1. Global middleware (CORS, logging, etc.)
2. Route-specific middleware
3. Route handler
4. Response

Core Components#

DartExpress

The main application class. Manages middleware, routing, and server lifecycle.

Request

Represents an HTTP request with helpers for:

• Path parameters: req.params['id']
• Query strings: req.query['search']
• Body parsing: await req.body
• Sessions: req.session
• Headers: req.headers

Response

Fluent API for building responses:

• res.text('Hello')
• res.json({...})
• res.status(404)
• res.cookie('name', 'value')

Router

Radix-tree based router for fast path matching with support for:

• Path parameters: /users/:id
• Wildcards: /files/*
• Method-based routing

Key Features#

Sessions#

Built-in session management with pluggable stores:

final app = DartExpress(
  sessionSecret: 'your-secret-key',
  sessionStore: MemorySessionStore(), // Default
);

app.get('/counter', (req, res) {
  final count = (req.session['count'] as int? ?? 0) + 1;
  req.session['count'] = count;
  res.json({'visits': count});
});

CORS#

One-line CORS configuration:

app.use(app.cors(
  allowedOrigins: ['https://example.com'],
  allowedMethods: ['GET', 'POST'],
  credentials: true,
));

Rate Limiting#

Protect your API from abuse:

app.use(app.rateLimit(
  maxRequests: 100,
  windowMs: 60000, // 1 minute
));

Dependency Injection#

Uses GetIt for service management:

final container = GetIt.instance;
container.registerSingleton(UserService());

app.get('/users', (req, res) {
  final userService = container<UserService>();
  res.json(userService.getAll());
});

Performance#

dart_express is designed for performance:

• Radix Tree Router: O(log n) route matching
• Zero-copy Body Parsing: Efficient request handling
• Async/Await: Non-blocking I/O throughout
• Isolate Support: Scale across CPU cores

Run benchmarks:

cd packages/dart_express/benchmark
dart run bin/run_benchmarks.dart

Comparison#

Examples#

Check out these complete examples:

• TODO API - Full REST API at /apps/dart_express_examples/todo_api_example
• Session Auth - Authentication demo at /apps/dart_express_examples/session_security_example
• MongoDB - Database integration at /apps/dart_express_examples/mongo_example

Contributing#

We welcome contributions! Check out our GitHub repository to:

• Report bugs
• Suggest features
• Submit pull requests
• Improve documentation

License#

dart_express is open source software licensed under the MIT license.

Ready to build something? Check out the GitHub repo to get started!