Website Redesign SEO: Migrate Without Losing Rankings

Pre-launch

Build a full URL inventory and one-to-one mapping from every old URL to its new equivalent before writing a single redirect rule.

Small and medium sites should move all URLs simultaneously; large sites may move one section at a time to isolate problems. [Google Search Central, Site moves with URL changes]

Skipping the full inventory step is the single most common cause of post-launch ranking loss, since any URL left unmapped simply returns a 404 the moment the new site goes live, silently discarding whatever equity that page had accumulated.

• Where a vendor's reporting disagrees with your own, treat the discrepancy as a definitions problem first, and trace both numbers back to their source before assuming either one is wrong.

Launch

Google recommends server-side permanent redirects, naming HTTP 301 and 308, and says to avoid chaining redirects. [Google Search Central]

Googlebot can follow up to 10 hops, but chains should ideally be no more than 3 and fewer than 5. [Google Search Central]

Measurement discipline tends to matter more in slow periods than in fast-growth periods, since a rigorous reporting model is what tells you honestly whether a slowdown is seasonal, competitive, or self-inflicted.

• Submit a Change of Address in Search Console for the old site, then update internal links and submit the new sitemap, removing the old one. [Google Search Central]
• A short written glossary of exactly how each metric in your report is defined saves significant time whenever a new team member or partner needs to be brought up to speed.

Post-launch

Keep redirects for as long as possible, generally at least one year, so Google can transfer signals and reassign external links. [Google Search Central]

Monitor both sites using Search Console, server access and error logs, and analytics, watching sitemaps, the index coverage report, and search queries. [Google Search Central]

Keep the old hosting environment or at minimum the redirect map accessible for the full retention period, since removing infrastructure early is a common and entirely avoidable way to accidentally break the redirect chain months after launch.

Diagnosing a post-migration drop

Google lists site moves and migrations as a distinct cause of traffic drops, and says URL changes can take a few weeks to be noticed on medium sites and longer on larger ones. [Google Search Central, Debugging search traffic drops]

Because of that lag, resist the instinct to make sweeping additional changes in the first week after launch if traffic dips; Google's own guidance suggests the drop may simply reflect the recrawl and reprocessing timeline, not a mistake in the migration itself.

Resist the temptation to build a bigger dashboard before fixing the definitions underneath it. A small, well-defined report beats a large, ambiguous one every time a real decision is on the line.

Rollback and escalation triggers

Set a clear threshold in advance, for example a sustained multi-week drop beyond seasonal norms, that triggers a full redirect and canonical audit rather than a wait-and-see approach.

Decide who has authority to call a rollback before launch day arrives, since making that decision under pressure, in the middle of an unexpected traffic drop, tends to produce worse outcomes than deciding it calmly in advance.

Share the same report format with every stakeholder, internal team and outside vendor alike, so that a disagreement about performance is a disagreement about facts rather than a disagreement about which numbers to trust.

A launch-day checklist

Redirects are the strongest canonicalization signal, and internal links should point to canonical URLs rather than duplicates, which is worth re-verifying the moment the new site goes live. [Google Search Central, Consolidate duplicate URLs]

Confirm on launch day that robots.txt on the new site is not accidentally blocking the crawlers it needs to welcome, since a leftover staging-environment robots.txt file is a recurring, entirely avoidable migration failure.

Revisit the reporting model itself every few months, not just the numbers inside it, since a metric that made sense a year ago can quietly stop reflecting what the business actually needs to know.

Frequently asked questions

Primary sources

Policy and statistical claims in this guide are grounded in the sources below. Access dates and policy details can change, so verify regulated guidance before acting.

• Google Search Central, Site moves with URL changes
• Google Search Central, Debugging search traffic drops
• Google Search Central, Consolidate duplicate URLs