Transaction Validation

Overview

Transaction validation determines whether an operation is permitted under the applicable blockchain state and rules. Checks can include encoding, signatures, nonce or input availability, balances, scripts, gas limits, and contract execution. Nodes often perform a policy check before mempool admission and a consensus check again within a proposed block. A transaction valid against one state may become invalid after a conflicting transaction executes or after a chain reorganization.

Implementations must produce identical consensus results for the same state and transaction, including edge cases and resource accounting. Wallet-side simulation improves feedback but cannot guarantee later inclusion because state and ordering can change. Services should record explicit failure reasons and distinguish invalid, rejected by policy, reverted during execution, expired, and replaced statuses.

These records allow a later rescan to reconstruct the result when an endpoint, webhook, or local index becomes unreliable. Operational records should retain the raw transaction, network identifier, sender and destination, asset and amount, block reference, execution status, and observed timestamps. Customer-facing status should describe what is known without overstating settlement. Unknown, pending, included, failed, replaced, and finalized conditions need separate handling, together with a recovery procedure for transactions whose observed state conflicts across providers.

Submission, peer acceptance, block inclusion, execution, confirmation, and finality provide different evidence, and a transaction can advance, stall, be replaced, or disappear from the canonical chain between those stages. Transaction Validation should be represented as a sequence of observable states rather than one success flag. Settlement consideration: Transaction validation is state-dependent and layered, so mempool acceptance, execution success, and consensus validity must not be conflated.