@mem-cash/validation

Stateless transaction evaluator for Bitcoin Cash. Validates raw transaction hex against consensus rules, policy checks, and libauth VM script verification.

Usage

import { createTxVerifier } from "@mem-cash/validation";

const verifier = await createTxVerifier({
  vmVersion: "BCH_2025_05",
  standard: true,
});

const result = verifier.verify(rawHex, sourceOutputs, chainState);
if (result.success) {
  console.log(result.txid, result.fee, result.validatedTx);
} else {
  console.log(result.code, result.error); // BCHN reject code + reason
}

Verification Pipeline

Matches BCHN's AcceptToMemoryPool order:

1. Decode transaction hex
2. Null prevout check (bad-txns-prevout-null)
3. Validate sourceOutputs count matches inputs (bad-txns-inputs-missingorspent)
4. Locktime finality (bad-txns-nonfinal)
5. Coinbase maturity (bad-txns-premature-spend-of-coinbase)
6. Unspendable inputs (bad-txns-input-scriptpubkey-unspendable)
7. Input value ranges (bad-txns-inputvalues-outofrange)
8. Output value ranges and fee computation (bad-txns-outputvalues-outofrange, bad-txns-in-belowout) -- per-output and cumulative sum checked against MAX_MONEY
9. BIP68 sequence locks (non-BIP68-final)
10. Min relay fee (min relay fee not met)
11. Absurd fee guard (absurdly-high-fee)
12. Dust check (dust)
13. VM script verification (mandatory-script-verify-flag-failed / non-mandatory-script-verify-flag)

All error strings and reject codes match BCHN exactly. The verifier implements BCHN's two-pass script verification to distinguish mandatory from non-mandatory failures.

Config Validation

createTxVerifier rejects non-positive minRelayFeePerKb and maxFee values at construction time to prevent bypassing fee policy checks.