# Baseline crawl

Category: [Relaunch & Migration](https://seo-geo-glossary.com/en/glossary/category/relaunch-migration/) › [Planning & mapping](https://seo-geo-glossary.com/en/glossary/category/relaunch-migration/planning-mapping/) · Also known as: Baseline

A **baseline crawl**, also called a benchmark crawl, is a full crawl of the current website taken before a major change such as a relaunch or migration. It records the starting state so that later crawls can be compared against it. The term comes from SEO practice and has no formal definition.

## What does it record?
For each URL, a baseline crawl stores whatever will be compared later. The following list is common SEO practice:

- status codes and existing redirects
- titles, headings and meta tags
- canonical tags and indexability
- internal links and click depth
- the number of indexable pages

Traffic sources and Core Web Vitals come from analytics and measurement tools. In the Sitebulb webinar, practitioners name them as benchmarks to capture before a migration.

## Why is it needed?
Google advises mapping old URLs to new ones before a site move, and a baseline crawl can supply the list of old URLs (practice; Google also names sitemaps, server logs and analytics for this). After launch, a new crawl is compared with the baseline: missing pages, changed titles or new redirect chains show up as differences. Siteimprove also lists a crawl of the staging environment as part of pre-launch validation, and a speaker in the Sitebulb webinar suggests crawling regularly in the run-up, since the site may keep changing.

## Example (fictional numbers)
The baseline holds 12,480 indexable URLs. The crawl after launch finds 11,900. The gap of 580 URLs can be checked one by one for missing redirects or removed pages.

## Related terms

- [Staging crawl](https://seo-geo-glossary.com/en/glossary/staging-crawl/index.md)
- [Crawl comparison](https://seo-geo-glossary.com/en/glossary/crawl-comparison/index.md)
- [Website relaunch](https://seo-geo-glossary.com/en/glossary/website-relaunch/index.md)
- [Website migration](https://seo-geo-glossary.com/en/glossary/website-migration/index.md)
- [Redirect mapping](https://seo-geo-glossary.com/en/glossary/redirect-mapping/index.md)
- [URL mapping](https://seo-geo-glossary.com/en/glossary/url-mapping/index.md)

## Sources

- [Site moves and migrations – Google Search Central](https://developers.google.com/search/docs/crawling-indexing/site-move-with-url-changes)
- [Website Migrations & Redirect Mapping Dos and Don'ts – Sitebulb (webinar transcript)](https://sitebulb.com/resources/guides/webinar-website-migrations-redirect-mapping-dos-donts/)
- [Technical SEO during migrations – Siteimprove](https://www.siteimprove.com/blog/technical-seo-during-migrations/)

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Last updated: October 7, 2026
URL: https://seo-geo-glossary.com/en/glossary/baseline-crawl/