Modules are smart contracts that inherit the AbstractModule contract and are registered in the registry. They allow for attestation creators to run custom logic to do things like:
  • verify that attestations conform to some business logic
  • verify a signature or a zk-snark
  • perform other actions like transferring some tokens or minting an NFT
  • recursively create another attestation
Modules are specified in a portal and all attestations created by that portal are routed through the specified modules. Modules can also be chained together into discrete pieces of specific functionality.
Each module exposes a public function called run:
function run(
AttestationPayload memory attestationPayload,
bytes memory validationPayload,
address txSender,
uint256 value
) public pure override {}
The function executes whatever logic it needs to, and reverts if the incoming transaction doesn't conform to the required logic. The attestationPayload is the raw data of the incoming attestation, and the validationPayload is any qualifying data required for verification, but that doesn't make it into the on-chain attestation, e.g. a snark proof, merkle proof or signature etc.
As well as implementing the Module interface, a module must also implement ERC-165 to ensure that it can be verified properly when being registered.

Module Metadata

Once the module smart contract is deployed, it can be registered with the following metadata:
(required) The address of the module smart contract
(required) A descriptive name for the module
string (URI)
(optional) A link to documentation about the module, its intended use, etc.
The metadata above is intended to help to discover modules that can be reused once created. Modules are chained together and executed in portals. The next section dives into portals, what they are, and how to create them.