what's CometBFT?

CometBFT is a distributed, Byzantine fault-tolerant consensus engine designed for building secure and scalable blockchain applications. As a fork and successor to Tendermint Core, it provides deterministic state machine replication, enabling developers to create sovereign blockchains with high throughput and instant finality. It powers the Cosmos ecosystem and supports the Interchain, allowing for interoperable networks where validators propose, pre-vote, and pre-commit blocks in a fault-tolerant manner, tolerating up to one-third malicious actors. The engine features an advanced Application Blockchain Interface (ABCI++) that decouples consensus from application logic, offering methods like ExtendVote and VerifyVoteExtension for enhanced flexibility in custom blockchain designs. CometBFT emphasizes security through cryptographic proofs and efficient light-client verification, making it suitable for decentralized finance, cross-chain bridges, and proof-of-compute systems. Its modular architecture supports upgrades and integrations, fostering innovation in the broader blockchain space without compromising on decentralization or performance.

CometBFT had a block time manipulation flaw discovered in Jan 2026, affecting all versions since 2015.