alloy-json-rpc

Core types for JSON-RPC 2.0 clients.

This crate includes data types and traits for JSON-RPC 2.0 requests and responses, targeted at RPC client usage.

Core model

A JSON-RPC call contains a method, an ID, and optional parameters; protocol notifications omit the ID. Alloy's client-oriented Request always serializes an id, with Id::None encoded as JSON null. Any type that implements RpcSend may be used as parameters. Parameters are omitted when their Rust type is zero-sized, such as () or [(); 0]; an empty Vec is still serialized as [].

Responses contain either a success value or an ErrorPayload. Client code usually handles them through RpcResult<T, E>, an alias for Result<T, RpcError<E>>:

• Ok(T) means the server returned a successful result.
• Err(RpcError::ErrorResp(_)) means the server returned a JSON-RPC error.
• Err(RpcError::NullResp) means a method that requires a value received JSON null.
• Other variants include serialization, deserialization, local usage, unsupported-feature, and transport failures.

The borrowed response aliases, such as BorrowedResponse and BorrowedResponsePacket, support inspecting payloads without first copying them. The client-oriented RpcRecv trait requires owned response types.

Most applications should use alloy-rpc-client or alloy-provider instead of constructing these protocol types directly.