Nonce

Every account on an EVM network has a nonce: the number of transactions it has sent. Each new transaction must use the next number. This stops a signed transaction from being replayed, and it fixes the order of an account's transactions.

The order is strict. If transaction 41 is stuck in the mempool because its fee is too low, 42, 43 and 44 wait behind it, however much they pay. Fixing it means replacing 41: sending a new transaction with the same nonce and a higher fee.

Why it matters for a payout system

• Two processes sending from one wallet at once can pick the same nonce, and one transaction will fail.
• A stuck payout blocks every later payout from that wallet on that network.
• Sweeps and payouts from the same address compete for nonces.

(In the API, "nonce" also means a one-time value in a signed request. See API request signing.)

On Valtu

Payouts from one wallet on one network go out in order, one nonce after another, and slow ones have their fees bumped. A wallet with a payout waiting isn't swept on that network, because the sweep would take the nonce and the funds the payout needs.