Gleam (programming language)

Gleam was originally created in 2016 by Louis Pilfold for a conference talk. It was later redesigned and adapted into what it is today.^[6]

The first numbered version of Gleam was released on April 15, 2019.^[12] Compiling to JavaScript was introduced with version v0.16.^[13]

In 2023 the Erlang Ecosystem Foundation funded the creation of a course for learning Gleam on the learning platform Exercism.^[14]

Version v1.0.0 was released on March 4, 2024.^[15]

In April 2025, Thoughtworks added Gleam to its Technology Radar in the Assess ring (languages & frameworks worth exploring). ^[16]

Gleam has seen some adoption in recent years.^[17] According to a blog post, the language creators have placed strong emphasis on developer experience (DX), which has contributed to its appeal.^{[18][better source needed]}

Although it compiles to run on the BEAM virtual machine, most new Gleam users do not have a background in Erlang nor Elixir, two older BEAM languages.^[19] In 2025, Louis Pilfold reported on results from the 2024 developer survey, which received 841 responses.^[19] Pilfold concluded that Gleam developers "overwhelmingly come from other ecosystems other than Erlang and Elixir".^[19] The core team also reported on Gleam's efforts to expand the BEAM ecosystem in a keynote talk at Code BEAM Europe 2024.^[20]

Developers have cited Gleam’s simplicity, static typing, and user-friendly tooling as reasons for adoption.^[21] The developer behind Nestful described their motivations for rewriting the project in Gleam as driven by its clarity and ease of use.^[22] There is a community-maintained list of companies using Gleam in production.^[23]

In 2025, Gleam appeared for the first time in the Stack Overflow Developer Survey, where it was the 2nd "most admired" language, with 70% of users currently using the language wanting to continue working with it.^[17] 1.1% of developer respondents reported doing "extensive development work" in the language over the past year.^[17]

Gleam includes the following features.^[8][24]

• Result type for error handling
• Immutable objects
• Algebraic data types
• Pattern matching
• No null pointers
• No implicit type conversions

A "Hello, World!" example:

import gleam/io

pub fn main() {
  io.println("hello, world!")
}

Gleam supports tail call optimization:^[25]

pub fn factorial(x: Int) -> Int {
  // The public function calls the private tail recursive function
  factorial_loop(x, 1)
}

fn factorial_loop(x: Int, accumulator: Int) -> Int {
  case x {
    1 -> accumulator

    // The last thing this function does is call itself
    _ -> factorial_loop(x - 1, accumulator * x)
  }
}

Gleam's toolchain is implemented in the Rust programming language.^[26] The toolchain is a single native binary executable which contains the compiler, build tool, package manager, source code formatter, and language server.^{[citation needed]} A WebAssembly binary containing the Gleam compiler is also available, enabling Gleam code to be compiled within a web browser.^[27] This is used in Gleam's interactive language tour^[28] and online playground.^[29]