Clean, composable web development for Gleam. No magic.

What is Dream?

Dream is a web toolkit for building servers. It’s not a framework—you control everything. No hidden configuration, no magic middleware appearing from nowhere. Your main() function shows exactly what’s happening.

Built for Gleam (a type-safe functional language) and runs on the BEAM (the same runtime that powers WhatsApp, Discord, and millions of concurrent connections).

A Quick Example

Here is the smallest useful Dream server. It responds with "Hello, world!".

import dream/http.{text_response, ok}
import dream/http/request.{Get}
import dream/router.{router, route}
import dream/servers/mist/server

fn index(_request, _context, _services) {
  text_response(ok, "Hello, world!")
}

pub fn main() {
  let app_router =
    router()
    |> route(method: Get, path: "/", controller: index, middleware: [])

  server.new()
  |> server.router(app_router)
  |> server.bind("localhost")
  |> server.listen(3000)
}

Run this: gleam run → Visit http://localhost:3000/ → See Hello, world!

In words:

• index is a controller: it takes a request/context/services and returns a response.
• router() and route(...) define which controller handles which requests.
• server.new() |> ... |> server.listen(3000) configures and starts a Mist-based HTTP server using a builder pattern.

Types are omitted here for brevity – Gleam can infer them. The quickstart walks through a fully-typed version line by line.

What Dream Can Do

Dream is more than “Hello, world”. Here are a few small examples of what it helps you build.

JSON APIs

fn get_user(request, context, services) {
  let user = find_user(services.db, id: 1)
  json_response(ok, user_to_json(user))
}

• Use Services to carry dependencies like a database pool.
• Use view functions (like user_to_json) to keep formatting separate from data access.

Streaming responses

fn download_log(request, context, services) {
  let stream = make_log_stream(services.log_store)
  stream_response(ok, stream, "text/plain")
}

• Send large responses as a stream of chunks.
• Use the BEAM’s strengths for long-running, memory-efficient operations.

WebSockets

fn chat(request, context, services) {
  websocket.upgrade_websocket(
    request,
    dependencies: make_dependencies(request, services),
    on_init: handle_init,
    on_message: handle_message,
    on_close: handle_close,
  )
}

• Upgrade an HTTP request to a typed WebSocket connection.
• Use explicit Dependencies instead of closures, so it’s clear what each handler needs.

See the guides for complete examples of JSON APIs, streaming, and WebSockets.

Why This Approach?

Everything is explicit. You can see exactly where your database connection comes from. No globals, no hidden state, no framework magic.

Controller actions are just functions. No base classes, no decorators, no inheritance. Extract parameters, do work, return a response.

Type-safe controllers. The compiler verifies your context and services types match across all controllers. However, path parameters are validated at runtime, not compile-time—this trade-off favors API ergonomics over compile-time safety. See Discussion #15 for details.

Composable, not opinionated. Use Dream’s patterns, or build your own. It’s just functions and data.

Learn More

• 📚 Complete Documentation - Guides, tutorials, and concepts
• 📖 API Reference - Complete API documentation on HexDocs
• 🚀 Quickstart - Get a server running
• 💡 Examples - Working code you can run

Why Gleam? Why the BEAM?

Gleam is a type-safe functional language. You get compile-time error checking, no nulls, and a modern syntax. Learn it in a weekend.

The BEAM is the runtime that powers Erlang and Elixir. It was built for reliability and concurrency:

• Millions of concurrent connections per server (WhatsApp: 2.8M per server)
• Fault tolerance - processes crash in isolation, the rest keep running
• Hot code reloading - update code without dropping connections

Real-world results:

• Discord: 12M+ concurrent users, 26M WebSocket events/sec with ~5 engineers
• Remote: Grew from zero to unicorn (~$3B) in ~2 years with Elixir
• BBC: Elixir serving almost all BBC web and app traffic

Gleam gives you the BEAM’s superpowers with type safety. You write functions. The BEAM handles concurrency, fault tolerance, and scaling.

Read more about why Gleam and the BEAM →

Philosophy

Dream is explicitly not a framework. We provide:

✅ Clean interfaces and types
✅ Common patterns (controllers, models, middleware)
✅ Useful utilities (validation, response builders)
✅ Working examples

You provide:

🎯 Your application structure
🎯 Your router configuration
🎯 Your controllers and models
🎯 Your business logic

No magic. No hidden behavior. Everything explicit.

Contributing

See the Contributing Guide for guidelines.

License

MIT License

Built with Gleam. Runs on the BEAM. Works like you’d expect.