Cairo Contracts

Reference for writing Cairo smart contracts on Starknet. Covers structure, storage, events, interfaces, components, and OpenZeppelin v3 patterns.

Optimization: After your contract compiles and tests pass, use the cairo-optimization skill as a separate pass.

When to Use

• Writing a new Starknet smart contract from scratch
• Adding storage, events, or interfaces to an existing contract
• Using OpenZeppelin components (Ownable, ERC20, ERC721, AccessControl, Upgradeable)
• Implementing the component pattern with embeddable_as
• Structuring a multi-contract project with Scarb

Not for: Gas optimization (use cairo-optimization), testing (use cairo-testing), deployment (use cairo-deploy)

Contract Structure

Every Starknet contract follows this skeleton: