Spry

Next-generation Dart server framework. Build modern servers and deploy them to the runtime you prefer.

Quick Start

Install the package:

dart pub add spry

Create a minimal project structure:

.
├─ routes/
│  └─ index.dart
└─ spry.config.dart

spry.config.dart

import 'package:spry/config.dart';

void main() {
  defineSpryConfig(
    host: '127.0.0.1',
    port: 4000,
    target: BuildTarget.dart,
  );
}

routes/index.dart

import 'package:spry/spry.dart';

Response handler(Event event) {
  return Response.json({
    'message': 'hello from spry',
    'runtime': event.context.runtime.name,
    'path': event.url.path,
  });
}

Start the dev server:

dart run spry serve

Core Ideas

routes/ defines request handlers with file routing
middleware/ and _middleware.dart shape cross-cutting request behavior
_error.dart provides scoped error handling
public/ serves static assets directly
spry.config.dart selects the runtime target and build behavior

Runtime Targets

Spry can emit output for:

Dart VM
Node.js
Bun
Deno
Cloudflare Workers
Vercel

WebSockets

Spry exposes websocket upgrades from the request event without introducing a second routing system.

import 'package:spry/spry.dart';
import 'package:spry/websocket.dart';

Response handler(Event event) {
  if (!event.ws.isSupported || !event.ws.isUpgradeRequest) {
    return Response('plain http fallback');
  }

  return event.ws.upgrade((ws) async {
    ws.sendText('connected');

    await for (final message in ws.events) {
      switch (message) {
        case TextDataReceived(text: final text):
          ws.sendText('echo:$text');
        case BinaryDataReceived():
        case CloseReceived():
          break;
      }
    }
  }, protocol: 'chat');
}

Current websocket support follows the underlying osrv runtime surface: