> ## Documentation Index
> Fetch the complete documentation index at: https://optimism-373f39ad-mintlify-908530ae.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# Using blobs

> Configure op-node to fetch L1 batcher blob data, including blobs older than the beacon retention window.

OP Stack rollups post batch data to L1 as [EIP-4844 blobs](https://eips.ethereum.org/EIPS/eip-4844). To retrieve this data, `op-node` requires access to an L1 beacon endpoint. Run your own beacon node ([Lighthouse](https://lighthouse-book.sigmaprime.io/run_a_node.html), Lodestar, Nimbus, Prysm, or Teku) or use a third-party service like [QuickNode](https://www.quicknode.com/docs/ethereum/eth-v1-beacon-genesis).

Pass the beacon endpoint to op-node:

```shell theme={null}
--l1.beacon value                                                      ($OP_NODE_L1_BEACON)
          HTTP endpoint Address of L1 Beacon-node.
```

## Configuring a blob archiver

Standard beacon nodes prune blobs after 18 days. If your node is synced within the last 18 days and stays online, the default beacon endpoint is sufficient. You need a blob archiver if either of these is true:

* You're syncing a new node from a snapshot or genesis older than 18 days
* Your node has been offline for more than 18 days

Pass one or more fallback endpoints to op-node:

```shell theme={null}
--l1.beacon-fallbacks value                                            ($OP_NODE_L1_BEACON_FALLBACKS)
          Addresses of L1 Beacon-API compatible HTTP fallback endpoints. Used to fetch blob sidecars
          not available at the l1.beacon (e.g. expired blobs).
```

<Info>
  `--l1.beacon-fallbacks` was previously called `--l1.beacon-archiver`. The old name still works as an alias, and so does the legacy env var `$OP_NODE_L1_BEACON_ARCHIVER`.
</Info>

Choose one of these options for the archiver endpoint:

* **Option 1 — Run a beacon node with blob pruning disabled.** For Lighthouse, set `--prune-blobs=false` and point `--l1.beacon-fallbacks` at it.
* **Option 2 — Run a dedicated blob archiver service** such as [base-org/blob-archiver](https://github.com/base-org/blob-archiver), and point `--l1.beacon-fallbacks` at its API endpoint. Lighter weight than running a full no-prune beacon node.
* **Option 3 — Use a third-party blob-archiver service.** Useful if you don't want to operate any beacon infrastructure.