# Chainlink Automation Service Limits
Source: https://docs.chain.link/chainlink-automation/overview/service-limits

> For the complete documentation index, see [llms.txt](/llms.txt).

## Maximum logs processed for log trigger upkeeps

Chainlink Automation nodes look back over a limited range of the latest blocks on any particular chain. During this process, the nodes process a limited number of logs per block per upkeep, using a minimum dequeue method to ensure that the latest logs are processed first. After this, the nodes may process additional remaining logs on a best effort basis, but this is not guaranteed. If you need all the remaining logs to be processed, configure a manual trigger as backup.

Expect the following numbers of logs to be processed:

| Chain     | Logs per block per upkeep                  |
| --------- | ------------------------------------------ |
| Ethereum  | 20                                         |
| BSC (BNB) | 4                                          |
| Polygon   | 4                                          |
| Avalanche | 4                                          |
| Gnosis    | 1                                          |
| OP        | 4                                          |
| BASE      | 4                                          |
| Arbitrum  | 1 log every 2 blocks, or 2 logs per second |

Note: Log triggers are not supported on Fantom.