# 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 CommitteeVerifier without additional configuration.
The underlying section goes into detail on the different verification models, interfaces, 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, and when to add custom or third-party verifiers.
- [Verification Models](/ccip/concepts/ccvs/verification-models): CommitteeVerifier, CCTPVerifier, LombardVerifier, and custom CCV attestation patterns.
- [CCV Interfaces & Guarantees](/ccip/concepts/ccvs/interface-guarantees): Onchain/offchain interface contracts, the versioned resolver pattern, and protocol guarantees.
- [Trust & Responsibility Model](/ccip/concepts/ccvs/trust-responsibility-model): Trust boundaries and responsibilities for default vs external CCV operators and integrators.