Deno

Deno is a free, open-source runtime for JavaScript, TypeScript and WebAssembly, built on Google's V8 engine and written in the Rust language. It was created by Ryan Dahl, who earlier created Node.js, with Bert Belder, and is developed by their company, Deno Land Inc. It is released under the MIT License.

History

Dahl announced Deno at JSConf EU in 2018, in a talk called "10 Things I Regret About Node.js" that listed the Node.js design choices he wanted to fix. Early versions were written in Go before the team moved to Rust. Deno 1.0 was released on 13 May 2020. The company launched Deno Deploy, a hosting service that runs code close to users around the world, in June 2021, and the Fresh web framework, built on Preact, in June 2022. Fresh sends no JavaScript to the browser by default and adds interactive "islands" only where a page needs them, the "islands architecture" popularised by Preact's creator Jason Miller. Deno 2, released on 9 October 2024, made it largely compatible with Node.js and npm packages; version 2.9, in June 2026, added packaging of desktop apps.

How it differs from Node.js

• Secure by default: a script cannot read files, use the network or see environment variables unless the user grants each permission with a command-line flag.
• TypeScript built in: TypeScript files run directly, with no separate compiler setup.
• One tool: a single program includes the runtime, package manager, formatter, linter, test runner and documentation generator.
• Web standards: it uses browser-style ES modules and web APIs such as fetch where Node.js historically had its own.