This is CCTP V1 version. For the latest version, see CCTP.
Before signing an attestation for a source chain event, Circle waits for a specified number of onchain block confirmations to achieve hard finality.
The table below shows the average time required for an attestation to become available after a message is emitted onchain.
Note: These values are subject to change.
| Source Chain | Number of Blocks | Average Time |
|---|---|---|
| Ethereum | ~65* | ~13 to 19 minutes* |
| Avalanche | 1 | ~8 seconds |
| OP Mainnet | ~65 ETH blocks* | ~13 to 19 minutes* |
| Arbitrum | ~65 ETH blocks* | ~13 to 19 minutes* |
| Noble | 1 | ~20 seconds |
| Base | ~65 ETH blocks* | ~13 to 19 minutes* |
| Polygon PoS | ~33 | ~75 to 120 seconds |
| Solana | 32 | ~25 seconds |
| Sui | 1 | ~8 seconds |
| Aptos | 1 | ~8 seconds |
| Unichain | ~65 ETH blocks* | ~13 to 19 minutes* |
Block confirmations for L2s to Ethereum
Layer 2 (L2) blockchains publish transaction data in batches to Ethereum L1, and the frequency of these posts varies by chain. Some submit batches every few minutes, while others are less frequent. After a batch is posted, Circle waits for the Ethereum L1 block containing the batch to finalize, which typically happens after ~65 blocks, or 13 to 19 minutes, before issuing an attestation.
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