Quantstamp

Its services include securing Layer 1 blockchains such as Ethereum 2.0 and Solana, securing smart contract-powered NFT and DeFi applications such as Maker and OpenSea, and developing financial primitives for Layer 1 blockchain ecosystems. Enterprise companies including Visa, Toyota, and Siemens also trust Quantstamp to secure their blockchain implementations.

Website: https://quantstamp.com/