Error codes

Every failed request call rejects with an error object:

interface ProviderRpcError extends Error {
  code: number;
  message: string;
  data?: unknown;
}

Handle the codes you can recover from, starting with the most common one — the user saying no:

try {
  await provider.request({ method: 'eth_requestAccounts' });
} catch (error) {
  switch (error.code) {
    case 4001:
      // User rejected — normal flow, don't show an error state.
      break;
    case -32002:
      // A request is already pending — point the user at the wallet
      // instead of firing the request again.
      break;
    default:
      console.error(error);
  }
}

Provider errors (EIP-1193)

Code	Name	What it means for your dapp
4001	User rejected request	The user dismissed the approval. Expected behaviour — never retry automatically.
4100	Unauthorized	The account or method has not been authorised. Connect first with eth_requestAccounts.
4200	Unsupported method	Core does not implement the method — for example eth_sign, which is rejected by design.
4900	Disconnected	The provider cannot serve any request. Listen for connect before retrying.
4901	Chain disconnected	Connected, but not to the chain the request targets.

JSON-RPC errors (EIP-1474)

Code	Name	Typical cause
-32700	Parse error	Malformed request payload
-32600	Invalid request	Request object missing required fields
-32601	Method not found	Typo in the method name, or a method the network's node does not expose
-32602	Invalid params	Wrong parameter count, type, or encoding
-32603	Internal error	The node failed to process an otherwise valid request
-32000	Invalid input / server error	Catch-all from the RPC node — inspect message
-32002	Resource unavailable / request pending	An approval window for the same request is already open

Practical rules

• 4001 is not an error state. Users decline requests all the time; treat it as a cancelled action.
• Don't queue duplicate prompts. If you receive -32002, the approval window is already open.
• Log error.data. Contract reverts from eth_call and eth_estimateGas usually carry the revert reason there.