Languages / Knowledge library

Gleam

beam and javascript targets with explicit result types

Typed functional language

Why learn Gleam?

Useful for typed code in the BEAM ecosystem or JavaScript hosts. Target-specific libraries and foreign functions require compatibility checks.

Where it came from

Gleam is a statically typed functional language that can target the Erlang runtime and JavaScript. Its tools include a compiler, formatter, build system, and package manager.

Build your understanding

Work through these exercises in order. Try the task before opening a reference.

Define a custom type and pattern match.
Return an explicit result for a fallible operation.
Add a package and run a test.
Inspect the selected compilation target.
Test a foreign-function boundary against its declared type.

Documentation and sources

Official project documentation (gleam.run)

Catalog research notes

Research snapshot: September 9, 2026. This entry summarizes the linked primary documentation; it does not assert a latest release version.

Connect the ideas

Explore next

Erlang Elixir JavaScript

Real World Example

Illustrative business scenario · AI-generated from linked documentation · Not a measured customer case study

Cross-Platform Inventory Synchronization

A retail logistics firm managing inventory across web dashboards and warehouse backend systems.

The business problem

Runtime errors and data mismatches occur when the web frontend and BEAM-based backend interpret shared inventory data structures differently, leading to inconsistent stock levels.

How this topic solves it

Gleam provides a unified type system that compiles to both JavaScript for the browser and the BEAM for the server, ensuring shared data models are strictly validated at compile-time on both targets.

Define shared inventory record types in a core Gleam module.
Implement logic for inventory updates using Result types to handle potential failures explicitly.
Compile the core module to JavaScript for the frontend and BEAM bytecode for the backend.
Integrate the generated TypeScript definitions into the web frontend to enforce type safety.
Use pattern matching on the Result type to handle synchronization errors gracefully.

Inventory Synchronization Flow · Process flow

Data flows from the shared Gleam source to platform-specific targets.

Gleam Source

Shared types and logic

BEAM Compiler

Target: Erlang VM

JS Compiler

Target: Browser/Node

Backend Service

Inventory Database

Web Dashboard

User Interface

Gleam Source → compiles to → BEAM Compiler
Gleam Source → compiles to → JS Compiler
BEAM Compiler → updates → Backend Service
JS Compiler → renders → Web Dashboard

Implementation example

This maps to the business scenario by using the Result type to ensure that inventory updates are handled safely, preventing runtime crashes in the warehouse backend or web dashboard.

gleam · Illustrative code; not executed or production-validated.

pub type InventoryError { OutOfStock DatabaseDown } 
// Explicit Result type forces handling of failure cases
pub fn update_stock(amount: Int) -> Result(Int, InventoryError) { 
  case amount { 
    n if n < 0 -> Error(OutOfStock) 
    n -> Ok(n) 
  } 
}

Expected business outcome

Developers achieve high confidence in data integrity across platforms, as the compiler prevents mismatched record fields or unhandled error states before deployment.

Limitations and checks

The primary trade-off is the overhead of maintaining a shared codebase that must remain compatible with both JavaScript and Erlang runtimes; developers can verify compatibility by running the Gleam compiler for both targets during the CI process.

Sources

Gleam programming language

Generated 2026-10-18 with gemini-3.1-flash-lite. Your assessment includes two questions about this example.

Catalog source: technology-maxxing. This page reproduces the existing catalog’s learning material and source links.