A founder called me last year about a week after his new site went live. The design was genuinely better. Faster, cleaner, mobile-first, everything the old one was not. Organic traffic was down 60 percent and still falling.
The design had nothing to do with it. His old services page lived at /services/commercial-plumbing and had ranked for eleven years. The new site called that page /what-we-do/commercial. The old address returned a 404. Every ranking, every backlink, every year of accumulated trust was attached to an address that no longer existed.
This is the entire story behind most post-redesign traffic collapses. It is a URL problem wearing a design problem's clothes.
Why redesigns lose traffic
Google does not rank your website. It ranks specific URLs. Everything it has learned about you over the years, which queries you answer well, who links to you, how people behave when they land, is filed against individual addresses.
Change the address without leaving a forwarding note and all of it stops. The new page starts from nothing, which is why a redesign can drop a business from position 3 to nowhere on a page that is objectively better written than what it replaced.
The forwarding note is a 301 redirect. Google's redirect documentation describes it plainly: Googlebot follows the redirect, and the indexing pipeline uses it as a signal that the target should become canonical. Google recommends a permanent server-side redirect whenever possible. That is the mechanism that moves your history to the new address.
Build the URL inventory first
Do this before anyone writes a line of the new site. You cannot map URLs you do not know about, and every site has pages the team forgot existed.
Use three sources, because none of them is complete on its own.
- Google Search Console. Export the Pages report going back the full 16 months. This is the most important list, because it is what Google has actually indexed rather than what you think you published.
- Google Analytics 4. Export landing pages for the last 12 months. This catches pages that convert but get few impressions.
- A full crawl. Screaming Frog is free up to 500 URLs, which covers most B2B SMB sites. This finds pages with no traffic that still hold inbound links.
Merge the three into one sheet and remove duplicates. On a typical 60-page B2B site you will end up with 90 to 150 URLs, and the surprises are usually old landing pages, PDFs, and blog posts from a previous agency.
Map every old URL to a new one
Add three columns: old URL, new URL, and a note. Then go line by line. This is dull work and it is the part that actually protects the launch.
Most rows are obvious. The ones that need a decision are the pages with no equivalent on the new site. Send those to the closest genuinely relevant page, which is usually the parent section. A retired service page goes to the services overview. A discontinued product goes to the category it sat in.
Do not send them to the homepage. Mass-redirecting old URLs to the homepage is the most common migration mistake and it is worse than doing nothing. When the destination does not match what the original page was about, Google treats it as a soft 404, which passes no ranking signal at all. You also drop every visitor arriving from an old link onto a page that does not answer the question they clicked for.
Let a URL return a genuine 404 only when it had no traffic, no rankings, and no inbound links. That is a small minority of any real site.
Write the redirects
Where the rules live depends on your host. On Cloudflare Pages or Netlify it is a _redirects file. On Apache it is .htaccess. On Nginx it is a server block. In WordPress a plugin will do it, though a server-level rule is faster.
Three things to get right.
Use 301, not 302. A 302 says temporary, and a temporary redirect tells Google to keep the old URL as the canonical one. Ranking signals do not consolidate. Teams pick 302 during testing and forget to change it, and the migration quietly fails while every URL appears to work fine in a browser.
Kill redirect chains. If A points to B and B points to C, you have a chain, and chains appear whenever a site goes through a second migration and nobody consolidates the old rules. Test every old URL and confirm it lands on its destination in one hop. When you add new rules, update the old ones to point straight at the current address instead of stacking on top of them.
Match trailing slashes to your host. Hosts differ on whether /services or /services/ is canonical, and writing a rule that fights your host's own behaviour creates an infinite redirect loop. Check which form your host canonicalizes to and write the rules to agree with it.
While you are in the markup, confirm every page carries a self-referencing canonical tag with an absolute URL. Google's canonicalization guidance calls redirects and rel=canonical annotations both strong signals, and warns against giving contradictory instructions through different methods. A redirect pointing one way and a canonical tag pointing another is exactly that contradiction.
The pre-launch check
Run this on staging, the day before you switch.
- Staging is blocked from indexing, and production is not. The single most expensive migration mistake is shipping the staging robots.txt with a site-wide disallow to production. That one file tells Google to drop everything.
- Titles and meta descriptions carried across instead of being replaced with template defaults. New CMS builds love to generate "Home | Company Name" for every page.
- Every URL in the mapping sheet resolves to its intended destination in one hop.
- Structured data survived the rebuild. If you had schema markup on service pages and FAQs, confirm it is still in the new templates, since it is easy to lose in a theme change.
- The XML sitemap lists only the new URLs and returns a 200.
If you are changing domains rather than just restructuring, submit a Change of Address in Search Console after the redirects are live and verified. Google's site move documentation is clear that this tool is only for moving between domains or subdomains, and is not needed for an HTTPS migration or a www switch on the same domain.
The first three weeks after launch
Resubmit the sitemap on day one and watch three things.
In Search Console, watch the Pages report for a rise in Not found errors. A handful is normal. A jump of dozens means your mapping missed a section. Also watch Core Web Vitals, because new designs routinely ship heavier pages, and a redesign that fixes your rankings problem while creating a speed problem has traded one issue for another.
In GA4, compare organic landing page traffic against the same weeks before launch. Look at the trend across weeks, not day to day. Some movement during a migration is expected and normal.
Google does not publish how long a site move takes to settle, and any specific number you see quoted is someone's estimate rather than official guidance. What Google does say is that after a domain move it will likely keep showing old URLs occasionally even once the new ones are indexed, and that this fades on its own. Judge recovery by the direction of the trend.
Worry when you see a steady decline across three consecutive weeks with rising 404s. That is a redirect gap, and it is findable: sort the Not found list by impressions before the launch and you will see exactly which pages fell through.
One release at a time
Resist the urge to redesign, restructure the URLs, and rewrite every page in a single launch. When traffic moves afterwards, and it will, you have no way to tell which of the three changes caused it.
Migrate the structure with the content as close to intact as you can. Confirm rankings hold for a few weeks. Then work through content improvements page by page, which is also when a content audit earns its keep. Slower on the calendar, far faster to diagnose.
The takeaway
A redesign does not cost you rankings. Broken addresses cost you rankings. The mapping sheet is a boring afternoon of work that protects every year of search equity the business has built, and it has to happen before launch.
Inventory the URLs. Map every one to a real destination. Keep the redirects for at least a year. Then ship the new design and enjoy it.