OpenZeppelin

Editor's pick
London, GB · est. 2015
9.5/10
★★★★★
20 reviews
Team size
50–249
Typical budget
$50,000+
Hourly rate
$200–400/hr
smart contract securitysmart contract auditsSolidityRustGoCairoDefender security toolsopen-source contract librariesDeFi security
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Editor's assessment: The definitive smart contract security standard — 900+ audits, library used by every major DeFi protocol.

OpenZeppelin is the global standard for smart contract security, having completed 900+ audits since 2017 across Solidity, Rust, Go, Cairo, and other languages. Founded in 2015 in San Francisco, OpenZeppelin’s open-source contract libraries are used in virtually every major DeFi protocol.

The company offers smart contract audits, security consulting, the Defender security operations platform, and ongoing security research. OpenZeppelin has audited contracts for MakerDAO, Compound, Uniswap, Aave, and hundreds of other protocols.

OpenZeppelin is not a full-stack development shop — it is the definitive security partner for DeFi protocols requiring the highest assurance audits and battle-tested contract libraries.