One key. Both runtimes.

Connect the wallet you already have

A Substrate wallet signs with sr25519 — the only signature this chain accepts for a contract call. TwinKey never sees your seed: the signature happens inside the extension.

EVM events, decoded read from Substrate, not eth_getLogs

The EVM endpoint's log index omits logs emitted by native-origin revive.call — including our own contract's. So this scans the Substrate event stream and decodes revive.ContractEmitted against the ABI instead.

Independent verdict Rust verifier, separate process

A second implementation with its own RPC readers checks that the state the EVM layer reports actually matches what was emitted on the Substrate side. If it is not running, this says so rather than inventing a verdict.

What a dApp developer changes: one line

Existing viem / wagmi / ethers code keeps working. The provider answers eth_call, eth_estimateGas, eth_sendTransaction and eth_getTransactionReceipt — the write goes out as a Substrate extrinsic signed by the user's own key.

import { createWalletClient, custom } from "viem";
import { createTwinKeyProvider } from "twinkey";

const twinKey = createTwinKeyProvider({ signer });   // polkadot.js, Talisman, SubWallet

const wallet = createWalletClient({ transport: custom(twinKey) });
const hash = await wallet.writeContract({
  address: "0x19d5aa109cbf0d4e0a126f1438ea73b619cb7725",
  abi, functionName: "setValue", args: [2077n],
});

const receipt = await wallet.waitForTransactionReceipt({ hash });
// receipt.logs[0].parsed -> { eventName: "ValueSet", args: { caller, value, callCount } }