The Superchain Registry is an index of chains which serves as the source of truth for who’s in the Superchain and what modifications they’ve made to their chains. It hosts Superchain-configuration data in a minimal human-readable form and includes mainnet and testnet Superchain targets, along with their respective member chains.

Other configuration, such as contract-permissions and SystemConfig parameters are hosted and governed onchain.

A list of chains in the registry can be seen in the top level chainList.toml and chainList.json files. These files are autogenerated from scripts in the registry and will remain stable to build against.

To help with clarity and a common understanding, here are some helpful terms and their definitions.

Superchain member: A chain with an agreement in place to commit sequencer revenue back to the Optimism Collective.
Blockspace charter: A Blockspace Charter is a technical-focused governing document (and framework) for the Superchain. Standard chain: A chain that conform to the Standard Rollup Charter - not ratified yet Frontier chain: A non-standard chain which has modifications that do not fit the Standard Rollup Charter criteria. Standard chain candidate: A chain that has met most of the standard chain criteria, except for the ProxyAdminOwner key handover.
Key handover: A colloquial term for updating the chain's ProxyAdminOwner to fulfill the requirements from the standard rollup charter.

Chains in the superchain-registry are assigned a superchain_level (shown in individual config files as well as the chainList.tom/json summaries), depending on the set of validation checks that they pass.

Frontier chains have superchain_level = 1.

Standard chains have superchain_level = 2. Because they satisfy a much stricter set of validation checks (see the Standard Rollup Blockspace Charter), they also qualify as Stage 1 rollups chains.

The superchain configs are stored in a minimal form, and are embedded in downstream OP-Stack software (op-node and op-geth). This means that, after a chain has been added to the registry, and the dependency on the registry updates in the downstream software, it is possible to start an op-node instance using the --network flag (and also an op-geth instance using the --op-network tag) which will successfully sync with other nodes on that network.

The following are the steps you need to take to add a chain to the registry:

You will be raising a Pull Request from your fork to the upstream repo.

Install the following dependencies

Make a copy of .env.example named .env, and alter the variables to appropriate values. Each value is explained in a comment in .env.example.

Run the following script from the root of the repository to open the PR.

just add-chain

The remaining steps should then be followed to merge the config data into the registry -- a prerequisite for promoting the chain to a standard chain.

The tool will write the following data:

• The main configuration source, with genesis data, and address of onchain system configuration. These are written to uperchain/configs/<superchain-target>/<chain-short-name>.toml.
• Hardfork override times, where they have been set, will be included. If and when a chain becomes a standard chain, a superchain_time is set in the chain config. From that time on, future hardfork activation times which are missing from the chain config will be inherited from superchain-wide values in the neighboring superchain.toml file.
• Genesis system config data
• Compressed genesis.json definitions (in the extra/genesis directory) which pull in the bytecode by hash

The genesis largely consists of contracts common with other chains: all contract bytecode is deduplicated and hosted in the extra/bytecodes directory.

The format is a gzipped JSON genesis.json file, with either:

• a alloc attribute, structured like a standard genesis.json, but with codeHash (bytes32, keccak256 hash of contract code) attribute per account, instead of the code attribute seen in standard Ethereum genesis definitions.
• a stateHash attribute: to omit a large state (e.g. for networks with a re-genesis or migration history). Nodes can load the genesis block header, and state-sync to complete the node initialization.

Run the following command to run the Go validation checks, for only the chain you added (replace the <chain-id> accordingly):

just validate <chain-id>

The validation_test.go test declaration file defines which checks run on each class of chain. The parameters referenced in each check are recorded in TOML files in the standard directory.

This tool will add your chain to the chainList.toml and addresses.json files, which contain summaries of all chains in the registry.

just codegen

When opening a PR:

• Open it from a non-protected branch in your fork (e.g. avoid the main branch). This allows maintainers to push to your branch if needed, which streamlines the review and merge process.
• Open one PR per chain you would like to add. This ensures the merge of one chain is not blocked by unexpected issues.

Once the PR is opened, the same automated checks you've run locally will then run on your PR, and your PR will be reviewed in due course. Once these checks pass, the PR will be merged.

This process is only possible for chains already in the registry.

Run this command (replace the <chain-id> accordingly):

just promote-to-standard <chain-id>

This command will:

• declare the chain as a standard chain
• set the superchain_time, so that the chain receives future hardforks with the rest of the superchain (baked into downstream OPStack software, selected with network flags).
• activate the full suite of validation checks for standard chains, including checks on the ProxyAdminOwner

MIT License, see LICENSE file.