Gleam Has a Free API: A Friendly Language for Building Type-Safe Systems

What if you could have Rust's type safety with Elixir's concurrency and JavaScript's friendliness? That's Gleam.

What Is Gleam?

Gleam is a type-safe functional language that runs on the BEAM (Erlang VM) and compiles to JavaScript. It combines:

• Erlang/Elixir's legendary concurrency and fault tolerance
• ML-family type system (like Rust, but friendlier)
• Clean, Python-like syntax
• Zero runtime errors from type mismatches

import gleam/io

pub fn main() {
  io.println("Hello from Gleam!")
}

Type Safety Without the Pain

// Types are inferred — you rarely need annotations
pub fn add(a: Int, b: Int) -> Int {
  a + b
}

// Custom types (like Rust enums)
pub type Shape {
  Circle(radius: Float)
  Rectangle(width: Float, height: Float)
  Triangle(base: Float, height: Float)
}

pub fn area(shape: Shape) -> Float {
  case shape {
    Circle(r) -> 3.14159 *. r *. r
    Rectangle(w, h) -> w *. h
    Triangle(b, h) -> 0.5 *. b *. h
  }
}
// Compiler ensures ALL cases are handled. Miss one → compile error.

Web Server (Wisp Framework)

import wisp
import gleam/http

pub fn handle_request(req: wisp.Request) -> wisp.Response {
  case wisp.path_segments(req) {
    ["api", "users"] -> list_users(req)
    ["api", "users", id] -> get_user(req, id)
    _ -> wisp.not_found()
  }
}

fn list_users(_req: wisp.Request) -> wisp.Response {
  let users = "[{"name": "Alice"}, {"name": "Bob"}]"
  wisp.json_response(string_tree.from_string(users), 200)
}

Why Gleam

• BEAM runtime — millions of concurrent connections, hot code reloading, fault tolerance
• No null, no exceptions — Result types for errors, Option for absence
• JavaScript target — share code between server and browser
• Interop — call Erlang/Elixir libraries directly
• Fast compilation — compiles in milliseconds

Gleam vs Elixir

Feature	Elixir	Gleam
Type system	Dynamic	Static
Runtime errors	Common	Rare
IDE support	Basic	Excellent (types!)
BEAM ecosystem	Full access	Full access
Learning curve	Medium	Low

gleam new my_project && cd my_project && gleam run

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Building type-safe systems? Check out my developer tools or email [e-mail].