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Validity Transactions let you submit a signed transaction with conditions on Base state. The API supports legacy, EIP-2930, and EIP-1559 transactions; EIP-1559 is recommended. Use them for conditional swaps, withdrawals, and other state-dependent actions.

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How It Works

Submit a signed raw transaction and a non-empty validity array. The current API supports balance, nonce, storage, and block-number predicates. Base rejects transactions that use the retired flashblock_index predicate. A transaction is eligible only when every predicate matches. Base checks predicates before inclusion. A pending transaction can become eligible after an earlier transaction changes the state it watches. EIP-1559 Validity Transactions use normal fee fields. Eligibility does not reserve block space or guarantee inclusion.

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Lifetime and Privacy

Use block_number predicates to constrain when a transaction can be included. Use the sender’s nonce when replacing a pending transaction. Validity criteria are sent separately from the signed transaction. They do not appear in the resulting onchain transaction. Do not include secrets in calldata or predicate values.

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Next Steps

Build a Validity Transaction

Sign and submit a transaction with Viem.

Validity Transaction RPC

Review the request format.

Predicates and Safety

Learn predicate rules, safety limits, expiry, and replacement.

Troubleshooting

Diagnose submission and inclusion issues.