Custom Chains

Engine supports all public EVM chains and your own custom chains.

You can define chain overrides allowing Engine to look up a chain ID's RPC URL, currency, and other metadata.

• Allow Engine to interact with your private or custom EVM chain.
• Bring your own RPC URL for an existing EVM chain.

When adding a chain override, Engine will use the provided chain metadata for the given chain ID.

Endpoint

POST /configuration/chains

Headers

• Authorization: Bearer <engine_access_token>
• Content-Type: application/json

Body

{
  "chainOverrides": [
    {
      "name": "My Custom Chain",
      "chain": "ETH",
      "rpc": [
        "https://my-custom-rpc-url.com"
      ],
      "nativeCurrency": {
        "name": "Ether",
        "symbol": "ETH",
        "decimals": 18
      },
      "chainId": 678,
      "slug": "my-custom-chain"
    }
  ]
}

Reference: POST /configuration/chains

Call Engine to get a chain's metadata or view all chain overrides.

• When calling the Engine API for a custom chain, provide the chain ID and not the chain slug. Chain slugs are only supported for public chains.

• Since Engine may be unable to resolve the ABI for your contract automatically, provide the ABI manually to call contract methods. We recommend providing the full function signature:

  POST /contract/:chainId/:address/write
  {
  	"functionName": "function setTokenURI(string uri)",
  	"args": ["ipfs://..."]
  }
  

  • Due to this reason, extension endpoints like erc721/transfer may not be supported for custom chains.

While you may interact with your custom chain from the Engine dashboard, the UI may not support your custom chain yet. To add it to the dashboard, follow these steps: