@causeway-sh/evm

EVM off-chain helpers for Causeway. Vault address derivation, EIP-1559 unsigned-tx + sighash construction, and signed-tx assembly. Works against any EVM-compatible chain (Ethereum, Base, Arbitrum, Optimism, Sepolia, anvil).

Install

pnpm add @causeway-sh/core@alpha @causeway-sh/evm@alpha

Quickstart

import {
  deriveVaultAddress,
  buildUnsignedTx,
  assembleSignedTx,
} from "@causeway-sh/evm";

const v = deriveVaultAddress({
  vaultThresholdPubkey, // 33 bytes — from the on-chain Vault account
  tenant,               // 32 bytes — the tenant program's id
  derivationPath,       // canonical Causeway path bytes
});
console.log(v.address); // "0xAbCd…" (EIP-55 checksummed)

const unsigned = buildUnsignedTx({
  chainId: 8453n,       // Base mainnet, for example
  nonce: 0n,
  maxPriorityFeePerGas: 1_000_000_000n,
  maxFeePerGas: 50_000_000_000n,
  gasLimit: 21_000n,
  to: "0xRecipient...",
  value: 1_000_000_000_000_000n, // 0.001 ETH (wei)
  data: "0x",
});

// run threshold signing round on `unsigned.sighash`, get (r, s, v)
const signedRaw = assembleSignedTx({ fields: unsigned.fields, r, s, v });
// broadcast `signedRaw` via any Ethereum JSON-RPC.

API

• deriveVaultAddress({ vaultThresholdPubkey, tenant, derivationPath }) — Causeway tweak → keccak256(uncompressedPubkey)[12..] → EIP-55 checksum. Returns { address, addressBytes, tweakedPubkey }.
• eip55Checksum(addressBytes) — standalone EIP-55 helper.
• buildUnsignedTx(args) — EIP-1559 unsigned RLP + 32-byte sighash.
• assembleSignedTx({ fields, r, s, v }) — splice (r, s, v) into the signed 0x02 ‖ rlp(...) wire form.

Status

Alpha. Base mainnet broadcasts have completed end-to-end through this SDK. Tested on Sepolia and anvil. The on-chain program is unverified bytecode and the protocol is not audited. Do not move funds you can't afford to lose.

License

Apache-2.0

Links

• Repository — https://github.com/causeway-protocol/sdk-ts
• Protocol — https://causeway.sh