# Cross-Chain Verifiers
Source: https://docs.chain.link/ccip/concepts/ccvs

> For the complete documentation index, see [llms.txt](/llms.txt).

Cross-Chain Verifiers (CCVs) are CCIP's pluggable verification layer. Each CCV attests that a source-chain message is valid before the destination chain executes it.

Most integrations use CCIP's default Committee Verifier without additional configuration. The pages below cover the verification models, interfaces and guarantees, and the trust and responsibility model for CCVs.

## Pages

- [Cross-Chain Verifiers Overview](/ccip/concepts/ccvs/overview): What CCVs are, how they fit into the message lifecycle, when to add custom or third-party verifiers, and how CCV requirements combine.
- [Verification Models](/ccip/concepts/ccvs/verification-models): The \`CommitteeVerifier\` , \`CCTPVerifier\` , and \`LombardVerifier\` attestation flows, custom CCVs, and how the models compare.
- [CCV Interfaces & Guarantees](/ccip/concepts/ccvs/interface-guarantees): The versioned resolver pattern, onchain and offchain interface requirements, optional access controls, and protocol guarantees.
- [Trust & Responsibility Model](/ccip/concepts/ccvs/trust-responsibility-model): Trust boundaries and responsibilities for default vs external CCV operators and integrators.