ERC‑7785: Reference Hub

Key specs, resolver docs, and interop resources mentioned across the app.

Overview of the chain registration system

ERC‑7785 defines a deterministic 32‑byte chain identifier derived from a chain’s name and supporting attributes.

This on‑chain Registry aims to replace ethereum‑lists/chains as the canonical source of chain metadata.

Registry (IChainRegistry)

Stores chain metadata (chain id, name); computes deterministic bytes32 identifier. Functions: register, demoRegister, chainData(bytes32).

Resolver (ChainResolver)

Maps human labels to identifiers; supports resolve(bytes,bytes) for reads. Helpers: computeNode, nodeToChainId, assign.

Contracts & Repos

Registry implementation — erc-7785-registry
ChainRegistry.sol — source
ChainResolver.sol — source

Flow through the contracts

Provide ChainData (name, settlement chain ID, version, rollup contract, CAIP‑2 namespace/reference, coin type).
Send a transaction to register(ChainData); on the Registry or use demoRegister to simulate.
The Registry derives bytes32 chainId via keccak256(abi.encode(...fields)). Read via chainData(chainId).
In the Resolver, map a label to chainId using assign. Helpers: computeNode → nodeToChainId.
Resolve reads: call resolve(bytes,bytes) (ENSIP‑10) with text(node, "chain-id").

CAIP‑2 Context & Mapping

The CAIP‑2 identifier is the chain selector in the form namespace:reference (for example, eip155:1 for Ethereum mainnet). This page lets you:

Resolve a CAIP‑2 identifier to its ChainData via the registry.
Reverse‑lookup from a CAIP‑2 hash to the chainId and ChainData.

The CAIP‑2 identifier is already present in ERC‑7930 chain‑aware addresses. By incorporating it into the ERC‑7785 chain identifier, we get a direct way to map an ERC‑7930 binary address back to its network using the chain’s CAIP‑2 identifier, and then fetch the authoritative ChainData from the registry.

Reference: ERC‑7785: CAIP‑2 and CAIP‑350 integration

Deployments (Sepolia)

Canonical deployment addresses used across this app.

Registry:0xB4ED82fa0EdC65f53af07C7A6032Ad40F7505275

Resolver:0x4874Bf6149dDf5F7B80664B3bDEB46193D7eb03c

CAIP‑2 Lib:0x02C9686bfc83aAA29fc19f8Ff39887d54B4Ef57a

Core Specs & Proposals

Standards that underpin the registry, resolver, and identifiers.

ERC‑7785 Proposal — Spec
Modified ERC‑7785 Proposal. This registry is based on this Spec — Pull Request
EIP‑155 — Settlement chain IDs
CAIP‑2 — Chain namespace and reference
ERC‑7930 — Chain‑aware addresses

ENS Resolvers

Standards and patterns used for reads via ENS.

ENSIP‑10 — resolve(bytes name, bytes data)
ENSIP‑11 — Coin types and formats

Interop & OP Stack

Optimism interop explainer.

OP Docs — Superchain interoperability