Website Migration Guide · Crawl and Indexing

How to Handle Crawl Budget During a Site Migration

After a migration, search engines need to re-crawl and re-index your new URLs. Here is what crawl budget is, how to manage XML sitemaps and robots.txt so crawlers work efficiently, and why it speeds re-indexing.

Updated: July 2026
Written by: Andrew Odgers, Managing Director
Reading time: 7 minutes
The short answer

Crawl budget is roughly how much crawling a search engine will do on your site in a given period, and it matters during a migration because search engines must re-crawl and re-index the new URLs. An updated XML sitemap lists your new URLs so crawlers find them efficiently, and submitting it tells search engines which pages now exist. Make sure robots.txt on the live site does not block important pages or the sitemap: a staging block left in place is a common, damaging mistake. Together, a correct robots.txt and an updated sitemap let the new site re-index quickly.

Helping crawlers focus

What crawl budget is, and how XML sitemaps help

Crawl budget is roughly how much crawling a search engine will do on your site in a given period, and it matters during a migration because search engines need to re-crawl and re-index the new URLs, so helping them focus on the right pages speeds up the process. If crawlers waste effort on redirects or unwanted URLs, re-indexing is slower; because a migration creates a lot to re-crawl, managing crawl budget helps the new site settle faster. XML sitemaps help during a migration because an updated XML sitemap lists all your new URLs so search engines can find and crawl them efficiently, and submitting it after launch tells them exactly which pages now exist. A clean, current sitemap points crawlers straight at the new structure, which is part of notifying Google of the migration; because it guides discovery of the new URLs, an accurate XML sitemap is one of the most useful tools for efficient re-crawling after a migration.

CR 01

Efficient re-crawl

Focus crawlers on new URLs.

CR 02

Updated sitemap

Lists the new structure.

CR 03

Correct robots.txt

Never block the live site.

Robots.txt, the classic mistake and re-indexing

Managing robots.txt, the staging block, and speeding re-indexing

You manage robots.txt during a migration by making sure robots.txt on the live new site does not accidentally block important pages or the sitemap, since a staging block left in place is a common and damaging mistake that can stop the new site being crawled at all. Checking robots.txt at go-live is essential; because a wrong robots.txt can hide the whole site from search engines, verifying it is correct on launch is a critical migration check. The staging robots.txt mistake is that a staging site is often blocked from crawling with robots.txt or a noindex, and the classic error is leaving that block in place when the site goes live, which tells search engines to ignore the new site. It is one of the most common causes of a migration going wrong; because it can prevent all indexing, removing any staging block at go-live is a check that must never be missed, and belongs on every migration checklist. Sitemaps and robots.txt speed re-indexing because together, a correct robots.txt that allows crawling and an updated sitemap that lists the new URLs let search engines find and re-index the new site quickly and without wasted effort, supporting a faster recovery of visibility. They clear the path and light the way for crawlers. Because they directly shape how efficiently the new site is discovered, getting both right helps the migration re-index smoothly.

SEO done properly, from £350 a month

Clear the path.
Let crawlers find the new site.

One wrong line in robots.txt can hide your whole new site from Google. We check robots.txt at go-live, submit an updated sitemap of your new URLs, and keep crawling efficient, so search engines re-crawl and re-index the new structure quickly and cleanly.

Everything included in your plan:

Google Maps optimisation Full website management Local SEO campaign AI optimisation (GEO) Facebook, Instagram and LinkedIn Quarterly audits Monthly reporting
£350 per month

One clear retainer. No setup fee.

Frequently asked

Crawl budget during migration

What is crawl budget and why does it matter during a migration?
Crawl budget is roughly how much crawling a search engine will do on your site in a given period, and it matters during a migration because search engines need to re-crawl and re-index the new URLs, so helping them focus on the right pages speeds up the process. If crawlers waste effort on redirects or unwanted URLs, re-indexing is slower. Because a migration creates a lot to re-crawl, managing crawl budget helps the new site settle faster.
How do XML sitemaps help during a migration?
An updated XML sitemap lists all your new URLs so search engines can find and crawl them efficiently, and submitting it after launch tells them exactly which pages now exist. A clean, current sitemap points crawlers straight at the new structure. Because it guides discovery of the new URLs, an accurate XML sitemap is one of the most useful tools for efficient re-crawling after a migration.
How should you manage robots.txt during a migration?
You make sure robots.txt on the live new site does not accidentally block important pages or the sitemap, since a staging block left in place is a common and damaging mistake that can stop the new site being crawled at all. Checking robots.txt at go-live is essential. Because a wrong robots.txt can hide the whole site from search engines, verifying it is correct on launch is a critical migration check.
What is the staging robots.txt mistake?
A staging site is often blocked from crawling with robots.txt or a noindex, and the classic mistake is leaving that block in place when the site goes live, which tells search engines to ignore the new site. It is one of the most common causes of a migration going wrong. Because it can prevent all indexing, removing any staging block at go-live is a check that must never be missed.
How do sitemaps and robots.txt speed re-indexing?
Together, a correct robots.txt that allows crawling and an updated sitemap that lists the new URLs let search engines find and re-index the new site quickly and without wasted effort, supporting a faster recovery of visibility. They clear the path and light the way for crawlers. Because they directly shape how efficiently the new site is discovered, getting both right helps the migration re-index smoothly.