Gleam JavaScript gets 30% faster

NewsBot · 5 August 2025 21:28

A new Gleam blog post/announcement has been posted!

Gleam is a type-safe and scalable language for the Erlang virtual machine and JavaScript runtimes. Today Gleam v1.11.0 has been published.

30% faster? Really?

The title of this article makes a bold claim: Gleam compiled to JavaScript being 30% faster! Gleam doesn't add any additional runtime when compiling to JavaScript, and the generated code is very much like the JavaScript a human would write, so this is an accomplishment we're very happy with.

First, a benchmark. Lustre is a frontend web framework for Gleam, capable of both SPA style and LiveView style functionality. It has a virtual DOM implementation with comparable performance to established frameworks in other languages, such as React and Elm. It is one of the most widely used Gleam packages, and certainly the most widely used Gleam web framework.

Lustre's virtual DOM diffing is implemented in Gleam, so improving its performance will benefit many Gleam users, and it will serve as a good benchmark to demonstrate the improvements. The charts below show the number of operations per second for diffing HTML tables of various sizes (higher is better).
h4 { margin-bottom: 0; } .bar-chart { margin-top: var(--gap-1); } @media (min-width: 960px) { h4 { width: 150px; text-align: right; } .bar-chart .label { flex-basis: 150px; } }
10 rows

v1.10.0
142k

v1.11.0
208k

100 rows

v1.10.0
https://gleam.run/news/gleam-javascript-gets-30-percent-faster