**Deno** is a [**TypeScript**](https://www.educative.io/answers/what-is-typescript) runtime built on #key# V8: Google's runtime engine for JavaScript #key#. **Node.js** is an open-source JavaScript runtime environment that is also built on V8 and written in C, C++, and JavaScript.

Both languages are intended to be used for web development. In fact, Deno was developed as a replacement to Node.js by the very person, Ryan Dahl, who made Node.js. Ryna Dahl announced Deno in 2018 in his famous talk, *'10 Things I Regret About Node.js'*. As the name of the talk suggests, Ryan aimed to fix some of the problems of Node.js in Deno.

### Deno
1. Deno has a huge focus on security. It runs all code in a sandbox, which prevents access to the file system. To access the file system, Deno asks permission first.
2. Deno uses URLs to import modules instead of a centralized registry like `npm`. While this is risky due to the unpredictability of the web, Deno attempts to reduce this problem by caching downloaded modules.
3. Deno has a built-in window object. A **window object** offers a representation of the browser's window.
4. Deno offers out-of-the-box support for TypeScript.

### Node.js
1. Node.js does not run in a sandbox and does not need permission to read or write in the file system.
2. Node.js uses Node Package Manager, commonly known as `npm`, which is a centralized system to import modules. Although convenient, `npm` has recently encountered a number of issues.
3. Node.js does not offer a built-in window object.
4. Node.js does not offer out-of-the-box support for TypeScript.

Deno vs. Node.js

Deno emphasizes security with sandboxed code, URL imports, and TypeScript support. Node.js uses npm, lacks sandboxing, and requires additional setup for TypeScript.