How it works
Ryan Dahl started Deno in 2018 to fix what he regretted about Node.js. Like Node it runs on the V8 engine, but its core is written in Rust and it runs TypeScript directly. A script cannot read files, open network connections or see environment variables unless you allow it with flags such as --allow-net, which limits the damage a compromised package can do.
Deno 2 made it largely compatible with Node.js and npm packages, so most existing libraries now work. It prefers web-standard APIs (fetch, Request, Response), can compile a program into a single executable, and has its own package registry, JSR. Deno Deploy hosts Deno code on a global network, and Supabase Edge Functions and Netlify Edge Functions both run on Deno.
Deno pros and cons
Pros
- TypeScript, formatter, linter and test runner work with no setup
- Permissions stop code touching files or the network without consent
- Web-standard APIs make code easy to move to edge platforms
- Runs most npm packages since Deno 2
Cons
- Smaller community and fewer guides than Node.js
- Some Node-specific packages and native add-ons still misbehave
- Fewer hosts treat it as a first-class option
When to use Deno
Pick it when
- New TypeScript projects that want built-in tooling and safer defaults
- Scripts and command-line tools that should not get full system access
- Supabase Edge Functions and other Deno-based platforms
Skip it when
- A large Node.js codebase with many native dependencies
Deno pricing
Open source
Free (MIT). Deno Deploy hosting has a free plan (about 1 million requests a month) and Pro at about $20 a month.
Deno pricing page (opens in a new tab)Approximate, checked September 2026.What the other tools cost
Deno vs the alternatives
Related terms
More in Backend and APIs
Runtimes