Deno is a secure run-time for JavaScript and TypeScript. Deno is based on Google's V8 engine that is developed by The Chromium Project and the programming language Rust. The project is the brainchild of Ryan Dahl, the original creator of Node.js, and aims to tackle issues around security and productivity. Ryan announced Deno during his speech 10 Things I Regret About Node.js at JSConf EU back in 2018.

What is Deno used for?

Deno can be used to build applications with JavaScript and TypeScript.

How is it Deno different from Node.js?

Deno is written in Rust, has TypeScript built-in, it utilize Promises / Async / Await and offer better default security mechanisms.

Why Deno?

Node.js was built in 2009, a time when the JavaScript eco-system and language looked a lot diffrent to what it looks today. Since 2009 JavaScript has introduced Promises / Async / Await, ES modules and Typed Arrays, we have also seen the introduction of TypeScript. All of which are not utilized to the full potential with Node.js. According to Ryan Dahl, the creator of both Node.js and Deno, Node.js has a poorly designed module system with centralized package management. Lot's of legacy APIs that must be supported, and a lack of default security. Hence Ryan decided to start from scratch with Deno an implementation of secure run-time for JavaScript and TypeScript written in Rust, that can be shipped as a single executable.