# Noir, the language behind Aztec smart contracts

> Noir is the open-source language every Aztec smart contract is written in. Stable at 1.0, with a versioned toolchain and a security-reviewed compiler.

Canonical: https://aztec.network/noir  
Type: Page summary  
Publisher: Aztec Foundation

## Questions

### What language are Aztec contracts written in?

Noir, an open-source language for zero-knowledge programs with Rust-like syntax, created by the Aztec team. Aztec contracts are written in Noir through the Aztec.nr framework, which adds storage, notes, nullifiers, and private and public functions. Noir also works with any proving backend and is used by projects outside Aztec.

Reviewed 30 October 2026  
Sources: [noir-lang.org](https://noir-lang.org)

### Can Noir be used outside Aztec?

Yes. Noir is an open-source language for zero-knowledge programs, created by the Aztec team and used well beyond Aztec. It works with any proving backend and runs in a browser, on a server, on a phone, or on another chain. ZKPassport, ZK Email, Payy, and StealthNote are written in Noir without running on Aztec.

Reviewed 30 October 2026  
Sources: [noir-lang.org](https://noir-lang.org)

### What changed in Noir 1.0?

Noir 1.0 is the first stable release. Syntax and semantics are stable across the 1.x series, the Nargo toolchain follows semantic versioning and can be pinned with noirup, the ACIR output is stable for proving backends, and the compiler has been through internal and external audits, fuzzing, and bytecode verification. For Aztec builders that means contracts keep compiling and the toolchain can be pinned; Aztec.nr targets Noir 1.0 from Aztec Tierra.

Reviewed 30 October 2026  
Sources: [Noir documentation](https://noir-lang.org/docs)

_This is a summary of https://aztec.network/noir, not its full text. Read the page for the whole argument._

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Markdown representation of https://aztec.network/noir. Published by Aztec Foundation.