Finality
The point at which a blockchain transaction becomes irreversible and can never be changed or rolled back.
Finality means "this transaction is done, permanently." Different blockchains achieve finality differently and at different speeds. Solana achieves finality in about 400 milliseconds. Avalanche in under 2 seconds. Ethereum takes about 15 minutes for full finality (though practical finality is much faster).
Why does this matter? Until a transaction reaches finality, there's a theoretical (though extremely unlikely) chance it could be reversed. Exchanges wait for a certain number of confirmations before crediting your deposit because they want to be confident the transaction is final.
For everyday USDC transfers between wallets, you don't need to worry much about finality. Your recipient sees the funds within seconds on most chains. It mainly affects large institutional transfers and exchange deposits.
Related Terms
Settlement
The final, irreversible transfer of an asset from one party to another. On blockchains, settlement happens when a transaction is confirmed.
Confirmation
The number of new blocks added to the blockchain after your transaction's block, indicating how settled the transaction is.
Blockchain
A distributed, immutable digital ledger that records transactions across a network of computers.
Validator
A computer that verifies transactions and adds new blocks to a proof-of-stake blockchain.
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This definition is provided for educational purposes. USDC.org is an independent resource and is not affiliated with Circle Internet Financial.