Logs
Logs (or event logs), is a way for smart contracts to communicate with the outside world by "documenting" small pieces of information. Event logs allow other people to know that something has happened without them having to query the contract directly.
The most common form of event logs today are ERC20 (and ERC721) token transfer events.
Table Columns
The example used is an USDC transfer to Crypto.com.
| Column Name | Description | Example |
|---|---|---|
log_index | The position of this log in the block that it belongs to. The first log has index 0. | 35 |
transaction_hash | Unique identifier of the transaction that this log belongs to. | 0x79dc5231dd97b54e464b084ea371b0af277b70d16fdf03808edd3608d90647ba |
transaction_index | The position of this transaction in the block that it belongs to. The first transaction has index 0. | 31 |
address | The address of the contract that emitted this log. | 0x8ac76a51cc950d9822d68b83fe1ad97b32cd580d |
data | Unindexed data containing further information of the event, encoded in hex. | 0x0000000000000000000000000000000000000000000000011503bb38b4c4ff74 |
topic0 | The keccak256 hash of a flattened event signature string. | 0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef |
topic1 | First indexed topic of the event. | 0x000000000000000000000000e24fe20ca3e903b0e10536e2d82d0a4817046ddb |
topic2 | Second indexed topic of the event | 0x00000000000000000000000072a53cdbbcc1b9efa39c834a540550e23463aacb |
topic3 | Third indexed topic of the event. | |
block_timestamp | The time when the block that contains this log was included on the blockchain. | 2022-08-08 18:47:12 |
block_number | The length of the chain, in blocks. | 20,268,966 |
block_hash | Unique identifier of the block that includes this log. | 0x91a41c7246a83b0245c4fbff9667329b47518e6070d2b6a4e24bc8d3b8761d2d |
Last updated