> ## Documentation Index
> Fetch the complete documentation index at: https://docs.eco.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Provers

> How the source-chain Portal verifies fulfillment before releasing an intent's reward.

A **prover** exposes evidence that an intent was fulfilled on its destination chain. The source-chain [Portal](/routes/architecture/portal) reads that evidence before releasing the [vault](/concepts/vaults) reward to the recorded claimant.

The intent's `reward.prover` identifies the contract trusted for this check. With the Routes API, inspect the prover in the returned intent. For a direct contract integration, choosing a prover also means choosing its verification model and chain configuration.

Cross-chain proof delivery can require messaging or a submitted proof. The **Local prover** reads fulfillment on the same chain, so it does not need a cross-chain message.

## Next steps

See [Prover architecture](/routes/architecture/provers/overview) for the interface, implementations, and integration constraints.


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