The story is always the same. The new site launches, everyone is pleased with it, and three weeks later the phone is quieter. Somebody checks, and the pages that used to bring in work are gone from Google.
The design did not cause that. The addresses did.
What actually goes wrong
Search engines do not rank websites. They rank pages, one address at a time. Ten years of a business existing produces a set of addresses that Google trusts, other sites link to, and customers have bookmarked.
Then the site is rebuilt, and /services/water-heater-repair becomes /what-we-do/plumbing/water-heaters. Nobody set up a redirect. The old address now returns a 404. Everything that address had earned goes with it, and the new page starts from nothing.
Multiply that by sixty pages and you have the quiet phone.
The same thing happens on a host move if the new server is missing rules the old one had, and on a domain change, and on the day someone decides every URL should end in a slash.
The redirect map is the whole job
Before anything launches, you need a spreadsheet with two columns: every address on the old site, and the address it becomes on the new one.
Get the full list of old addresses. Three sources, and you want all three. Export every page Google knows about from Search Console under Pages. Export your top landing pages from your analytics for the last twelve months. Run a free crawler like Screaming Frog against the live old site. Each source finds pages the others miss, particularly old landing pages nothing links to any more that still quietly bring in traffic.
Match each one to its new home. Point it at the closest equivalent page, not the homepage. Redirecting fifty deleted pages to the homepage is treated as a soft 404 and passes on nothing. If there is genuinely no equivalent, decide deliberately: redirect to the nearest category, or let it return a 410 and accept the loss.
Use 301, not 302. A 301 says moved permanently and passes the ranking signals along. A 302 says temporary and does not, reliably. This is a one-character difference in a config file and it is the most common technical mistake in a migration.
Never chain redirects. Old page to interim page to final page loses value at every hop and slows the browser down. Point each old address straight at its final destination, even if that means rewriting rules you set up two years ago.
Everything else that has to move
Redirects are most of it. These are the rest, and they are the ones people forget.
Titles and meta descriptions. New templates often generate them fresh. A page that ranked with a carefully written title and now says “Home | New Site” will drop. Carry them across deliberately.
Headings and body copy. A redesign that keeps the layout but replaces 800 words of specific text with 200 words of atmosphere will lose rankings, and the redirect map will look perfect while it happens. Search engines were ranking that page for the words that are now gone.
Images and their alt text. Image URLs change too, and image search sends real traffic to some businesses.
Structured data. If the old site marked up your business details, hours, or reviews, and the new one does not, your listing appearance can change.
Canonical tags. Check they point at the new addresses and not, as happens more often than you would think, at the staging site.
The robots.txt file and the noindex tags. This is the one that ends careers. Staging sites are blocked from search so nobody finds them early. If that block ships to production, the entire site disappears within days. Check it on launch day, then check it again the next morning.
The order to do things in
Before launch. Build the redirect map and have someone other than its author check a sample. Crawl the staging site for broken links and missing titles. Record your current rankings and organic traffic so you have a baseline to compare against, because “it feels slower” is not evidence.
Launch day. Push it, then immediately fetch a dozen old addresses and confirm each returns a 301 to the right place. Check robots.txt on the live domain. Confirm the analytics tag is actually on the new pages, since losing tracking makes a normal dip look like a catastrophe.
The first week. Submit the new sitemap in Search Console. Watch the Pages report for a spike in 404s or “excluded by noindex”. Crawl the live site once more, looking specifically for redirect chains you did not intend.
The first month. Expect a dip. A wobble of 10 to 20 percent for two to four weeks is normal even on a clean migration, because search engines have to recrawl and reassess everything. Recovery to previous levels usually lands somewhere between four and eight weeks.
What is not normal is a 60 percent drop, or a dip that is still deepening in week six. That is a redirect problem, and the sooner you look the less it costs.
Things that make it harder than it needs to be
Changing the domain and the design and the platform on the same day. Each one is a variable. Change all three and you cannot tell which one caused the problem. If you can stage them, do.
Launching on a Friday. Nothing goes wrong until Saturday morning.
Deleting the old site immediately. Keep a copy. You will want to check what a page used to say.
Assuming the new platform handles it. Some do a decent job of redirecting their own old structure. None of them know about the landing page your last agency built in 2019.
If you have already lost traffic
It is usually recoverable, and the diagnosis takes an hour.
Open Search Console and compare the last month to the same month last year. Look at the Pages report for a jump in “not found”. Take your list of previous top pages, request each one in a browser, and see what actually happens. In most cases you will find a block of addresses returning 404s that nobody mapped.
Add the missing redirects. Recovery is not instant, because those pages have to be recrawled, but the signals are usually still there to be reclaimed for months afterwards. The businesses that never recover are the ones that waited a year before looking.
