> ## Documentation Index
> Fetch the complete documentation index at: https://docs.pulsy.app/llms.txt
> Use this file to discover all available pages before exploring further.

# Reorg Handling

> Learn how Atria handles chain reorganizations.

# Reorg Handling

Blockchain reorganizations can replace previously observed blocks. Atria tracks block hashes and parent hashes so the Ingestor can detect when the local chain view diverges from the network.

## Detection

For each new block, the Ingestor compares the block parent hash with the stored hash of the previous block. A mismatch indicates a possible reorg.

## Response

When a reorg is detected, Atria searches back to a common ancestor, rewinds stored state, and publishes a reorg event.

```mermaid theme={null}
flowchart LR
  NewBlock[New block] --> Compare[Compare parent hash]
  Compare --> Match{Matches stored hash?}
  Match -->|Yes| Store[Store block]
  Match -->|No| Rewind[Find ancestor and rewind]
  Rewind --> Event[Publish reorg event]
```

## Feed Impact

Feeds receive metadata that includes `isReorg`. Feed authors can use this field when they need reorg-aware behavior.

For payload shapes, see [data types](/atria/core-concepts/data-types).