<commit_before># Checkpoint Sync

Lighthouse supports syncing from a recent finalized checkpoint. This is substantially faster
than syncing from genesis, while still providing all the same features.

If you would like to quickly get started with checkpoint sync, read the sections below on:

1. [Automatic Checkpoint Sync](#automatic-checkpoint-sync)
2. [Backfilling Blocks](#backfilling-blocks)

The remaining sections are for more advanced use-cases (archival nodes).

## Automatic Checkpoint Sync

To begin checkpoint sync you will need HTTP API access to another synced beacon node. Enable
checkpoint sync by providing the other beacon node's URL to `--checkpoint-sync-url`, alongside any
other flags:

```
lighthouse bn --checkpoint-sync-url "http://remote-bn:5052" ...
```

Lighthouse will print a message to indicate that checkpoint sync is being used:
<commit_msg>Add minimum supported version for checkpoint sync in book (#2779)<commit_after># Checkpoint Sync

Since version 2.0.0 Lighthouse supports syncing from a recent finalized checkpoint. This is
substantially faster than syncing from genesis, while still providing all the same features.

If you would like to quickly get started with checkpoint sync, read the sections below on:

1. [Automatic Checkpoint Sync](#automatic-checkpoint-sync)
2. [Backfilling Blocks](#backfilling-blocks)

The remaining sections are for more advanced use-cases (archival nodes).

## Automatic Checkpoint Sync

To begin checkpoint sync you will need HTTP API access to another synced beacon node. Enable
checkpoint sync by providing the other beacon node's URL to `--checkpoint-sync-url`, alongside any
other flags:

```
lighthouse bn --checkpoint-sync-url "http://remote-bn:5052" ...
```

Lighthouse will print a message to indicate that checkpoint sync is being used:

{'fraction_non_alphanumeric': 0.06993392070484582, 'fraction_numerical': 0.010462555066079295, 'mean_word_length': 4.9185667752443, 'pattern_counts': {'":': 0, '<': 3, '<?xml version=': 0, '>': 3, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
{'dir': 'git-commits-cleaned', 'id': '6116636', 'n_tokens_mistral': 506, 'n_tokens_neox': 457, 'n_words': 232}