# Diffs & crawl history

> Read what changed between two crawls of a watched URL, including the added and removed content, and work through the recorded crawl history.

Open any watch to see its **crawl history** — one entry per crawl attempt, newest first — and the
**diff** for each crawl that changed.

## What a crawl records

Every crawl attempt produces a history entry, whether or not the page changed:

- **Changed** — the entry carries a diff of inserted and removed content versus the previous snapshot.
- **No change** — recorded with an empty diff, so you can see the page was checked and was stable.
- **First crawl** — establishes the baseline snapshot; there's nothing to diff against yet.
- **Error** — the page couldn't be fetched or rendered; the entry notes the error.

## Reading a diff

A diff is a set of chunks marking text that was **added** or **removed** since the last crawl. The
detail view renders these inline so you can scan what changed at a glance and open the
rendered page snapshot itself.

## Next steps

<CardGrid>
  <Card title="Quotas & limits" href="/url-watch/quotas">
    How checks are counted and how to make your quota last.
  </Card>
  <Card title="Stream overview" href="/stream/overview">
    Watch the whole web for a pattern instead of a fixed URL list.
  </Card>
</CardGrid>