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Version: v0.19.4

Introducing Noir

What is Noir?

Noir is a Domain Specific Language for SNARK proving systems. It has been designed to use any ACIR compatible proving system.

It's design choices are influenced heavily by Rust and focuses on a simple, familiar syntax.

Who is Noir for?

Noir can be used for a variety of purposes.

Solidity Developers

Noir currently includes a command to create a Solidity contract which verifies your Noir program. This will be modularised in the future; however, as of the alpha, you can use the nargo codegen-verifier command to create a verifier contract.

Protocol Developers

As a protocol developer, you may not want to use the Aztec backend due to it not being a fit for your stack, or maybe you simply want to use a different proving system. Since Noir does not compile to a specific proof system, it is possible for protocol developers to replace the PLONK-based proving system with a different proving system altogether.

Blockchain developers

As a blockchain developer, you will be constrained by parameters set by your blockchain (for example, the proving system and smart contract language has been pre-defined). In order for you to use Noir in your blockchain, a proving system backend and a smart contract interface must be implemented for it.

What's new about Noir?

Noir is simple and flexible in its design, as it does not compile immediately to a fixed NP-complete language. Instead, Noir compiles to an intermediate language (ACIR), which itself can be compiled to an arithmetic circuit (if choosing to target Aztec's barretenberg backend) or a rank-1 constraint system (if choosing to target an R1CS backend like Arkwork's Marlin backend, or others).

This in itself brings up a few challenges within the design process, but allows one to decouple the programming language completely from the backend. This is similar in theory to LLVM.

Current Features


  • Module System
  • For expressions
  • Arrays
  • Bit Operations
  • Binary operations (<, <=, >, >=, +, -, *, /, %) [See documentation for an extensive list]
  • Unsigned integers
  • If statements
  • Structures and Tuples
  • Generics


  • Sha256
  • Blake2s
  • Schnorr signature verification
  • MerkleMembership
  • Pedersen Commitment
  • Pedersen Hash
  • HashToField


Noir does not currently have an official package manager. You can find a list of available Noir libraries in the awesome-noir repo here.

Some libraries that are available today include:

  • Standard Library - the Noir Standard Library
  • Ethereum Storage Proof Verification - a library that contains the primitives necessary for RLP decoding (in the form of look-up table construction) and Ethereum state and storage proof verification (or verification of any trie proof involving 32-byte long keys)
  • BigInt - a library that provides a custom BigUint56 data type, allowing for computations on large unsigned integers
  • ECrecover - a library to verify an ECDSA signature and return the source Ethereum address
  • Sparse Merkle Tree Verifier - a library for verification of sparse Merkle trees
  • Signed Int - a library for accessing a custom Signed Integer data type, allowing access to negative numbers on Noir
  • Fraction - a library for accessing fractional number data type in Noir, allowing results that aren't whole numbers

See the section on dependencies for more information.