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

# Freshness

> Latency targets and validation routines for keeping datasets current.

## Freshness by channel

BlockDB processes datasets in a coordinated pipeline, so most tables advance together. The main differences you observe in freshness come from **delivery channel** and **chain-specific reorg/finality buffers**.

| Delivery Channel                     | Typical Freshness | Notes                                                                                       |
| ------------------------------------ | ----------------- | ------------------------------------------------------------------------------------------- |
| **Real-time (WSS)**                  | Lowest latency    | Reorg-aware: you may see updates for recent blocks within the real-time buffer window.      |
| **API (REST)**                       | Near-real-time    | Stability guaranteed via chain-specific backoff beyond max reorg; queries are reproducible. |
| **Warehouse shares**                 | Hourly            | Freshness depends on provider and replication cadence.                                      |
| **Bulk exports<br />(SFTP/S3/Blob)** | Nightly snapshots | Nightly by default; hotfix replays are run ad-hoc if needed.                                |

## Chain buffers (blocks)

| Chain ID | Chain            | API & Archive buffer (blocks) | WSS buffer (blocks) | Rationale                                                                                                    | Source                                                                    |
| -------- | ---------------- | ----------------------------- | ------------------- | ------------------------------------------------------------------------------------------------------------ | ------------------------------------------------------------------------- |
| `1`      | Ethereum Mainnet | `3`                           | `0`                 | Etherscan forked-block data shows observed reorgs are almost always one block, we set the buffer above that. | [https://etherscan.io/blocks\_forked](https://etherscan.io/blocks_forked) |

<Info>
  These values are operational defaults and may change over time as chains evolve. If you need stricter guarantees for a specific chain, contact support.
</Info>

### How do I monitor data freshness?

* Use the `_updated_at` column for the dataset you query.
* For API pagination, you can also monitor the response `cursor` progression and returned `count` over time.

<Callout icon="lightbulb" color="#3B82F6" iconType="regular">
  Need tighter guarantees? Mirror the dataset via the API and compare `_tracing_id` values. Differences indicate your mirror is stale or queried inside the reorg buffer.
</Callout>