Our work

Cairo fully documented for better dev UX.

Cairo is the language behind Starknet smart contracts. Its core library is the code every Cairo program builds on, and it was thinly documented. We documented it for Starkware, so developers can learn it from their editor instead of its source code.

Client: Starkware
Project: Cairo Core Library
Date: Nov 2024 to Jan 2025

Overview

What is the Cairo core library?

Cairo is a programming language for provable programs, and Starknet smart contracts are written in it. The core library is the set of building blocks that ships with the language: arrays, integers, storage, cryptography tools and more. Every Cairo package gets it by default, so every Cairo developer depends on it.

The problem

Code with little explanation

In late 2024 the whole library held about 1,600 lines of documentation. A developer who wanted to know what a function did, or how to call it, was mostly left to read the source. That slows down experienced teams, and it is a hard way to learn a new language.

What we did

Documentation where developers work

We went through the library module by module, from arrays to storage, and wrote what each part does and how to use it, with examples. The work was merged into the Cairo repository through 75 pull requests, and the library came out with more than 8,000 lines of documentation.

We wrote it as comments in the source, so one text reaches developers in two places. The Cairo language server shows it when you hover over a function in your editor, and the public reference is generated from it. Newcomers get working examples, and teams get answers without leaving their code.

Contact our team

We take 4 protocols per quarter. Formal verification demands deep focus. We'd rather verify fewer contracts well than many poorly.

Learn more

Core library reference on the Starknet docs site.

Source on GitHub, where the documentation lives next to the code.

The Cairo Book, the guide to the language. Read about our work on it.