EIP155 Namespace, aka EVM Chains - JSON-RPC Provider Authorization

Author Pedro Gomes, Hassan Malik, bumblefudge
Status Draft
Type Standard
Created 2024-02-05
Updated 2024-02-05
Requires CAIP-25, CAIP-211, CAIP-217


For context, see the CAIP-25 specification.


In the Ethereum space, many networks interact in a given application or session, and as such it is necessary for applications and user-agents like wallets to negotiation and authorize interfaces dynamically and mutually. The CAIP-25 negotiation allows for multiple CAIP-217 authorization scopes to be negotiated together.

Network-specific versus Namespace-wide Scopes

Authorizing permissions and capabilities to each network separately (i.e., in its own CAIP-217 authorization object) is recommended in most use-cases, so that over the session and across sessions, each network can granularly gain or attenuate permissions and capabilities separately. Conversely, an authorization object scoped to all of eip155 can only add or substract individual networks from the chains array, or add and substract capabilities to all enumerated networks in that array.

It is also worth mentioning that if a network supports any capabilities NOT supported by other networks, they should never share an authorization object, as the semantics of CAIP-217 interpret this as supporting EVERY capability listed on EVERY network listed.

In such cases, not only is a separate authorization object recommended, but an explicit CAIP-211 declaration of the RPC authority where these network-specific capabilities are specified is also recommended; see the eip155/caip211.md profile for further guidance on using method and notification definitions which are not universal to the eip155 namespace.

Session Properties

No namespace-wide or network-specific session properties have yet been proposed for standardization. When crafting such properties for contextual/in-network usage, it is recommended to align one’s semantics and syntax (including case-sensitive style guides for property names!) with the EIP-6963 wallet provider interface (which extends the EIP-1193 interface) for common properties across architectures, making sure to avoid any collisions.

Similarly, wherever possible, session properties should align closely with information passed as JSON objects by wallet_ RPC methods, like capabilities or permissions. For example, the capability objects keyed to hexidecimal EIP-155 chainIds defined as the expected return content of the wallet_getCapabilities method in EIP-5792 should also be valid keyed the same way in sessionProperties.capabilities.


Example Request

{ “id”: 1, “jsonrpc”: “2.0”, “method”: “provider_authorize”, “params”: { “requiredScopes”: { “eip155”: { “scopes”: [“eip155:1”, “eip155:137”], “methods”: [“eth_sendTransaction”, “eth_signTransaction”, “eth_sign”, “get_balance”, “personal_sign”], “notifications”: [“accountsChanged”, “chainChanged”] }, “eip155:10”: { “methods”: [“get_balance”], “notifications”: [“accountsChanged”, “chainChanged”] }, “wallet”: { “methods”: [“wallet_getPermissions”, “wallet_switchEthereumChain”, “wallet_creds_store”, “wallet_creds_verify”, “wallet_creds_issue”, “wallet_creds_present”, “wallet_getCapabilities”], “notifications”: [] }, “cosmos”: { … } }, “optionalScopes”:{ “eip155:42161”: { “methods”: [“eth_sendTransaction”, “eth_signTransaction”, “get_balance”, “personal_sign”], “notifications”: [“accountsChanged”, “chainChanged”] }, “sessionProperties”: { “expiry”: “2022-12-24T17:07:31+00:00”, “caip154”: { “supported”:”true” } }
} }

Example Response

```json { “id”: 1, “jsonrpc”: “2.0”, “result”: { “sessionId”: “0xdeadbeef”, “sessionScopes”: { “eip155”: { “chains”: [“eip155:1”, “eip155:137”], “methods”: [“eth_sendTransaction”, “eth_signTransaction”, “get_balance”, “eth_sign”, “personal_sign”] “notifications”: [“accountsChanged”, “chainChanged”], “accounts”: [“eip155:1:0xab16a96d359ec26a11e2c2b3d8f8b8942d5bfcdb”, “eip155:137:0xab16a96d359ec26a11e2c2b3d8f8b8942d5bfcdb”] }, “eip155:10”: { “methods”: [“get_balance”], “notifications”: [“accountsChanged”, “chainChanged”], “accounts:” [] }, “eip155:42161”: { “methods”: [“personal_sign”], “notifications”: [“accountsChanged”, “chainChanged”], “accounts”:[“eip155:42161:0x0910e12C68d02B561a34569E1367c9AAb42bd810”] }, “wallet”: { “methods”: [“wallet_getPermissions”, “wallet_switchEthereumChain”, “wallet_getCapabilities”], “notifications”: [] }, “cosmos”: { … } },
“sessionProperties”: { “capabilities”: { “0xab16a96d359ec26a11e2c2b3d8f8b8942d5bfcdb”: { “0x31”: { “paymasterService”: { “supported”: true }, “sessionKeys”: { “supported”: true } }, “0x3432313631”: { “sessionKeys”: { “supported”: false }
} } }
} } }


  • [EIP155][]: Ethereum Improvement Proposal specifying generation and validation of ChainIDs


Copyright and related rights waived via CC0.


Please cite this document as:

Pedro Gomes, Hassan Malik, bumblefudge, "namespaces/eip155-caip25: EIP155 Namespace, aka EVM Chains - JSON-RPC Provider Authorization [DRAFT]," Chain Agnostic Namespaces, eip155-caip25, February 2024 / February 2024. [Online serial]. Available: https://github.com/ChainAgnostic/namespaces/eip155-caip25.md