A new website starts by inheriting an old one
Ask a company that replaced its website last year and the story rarely begins with design. It begins with something that broke quietly.
A plumbing company in Prague had six service pages and one quote form. The replacement, built with AI assistance in about a week, had twelve pages and a booking widget. Three weeks after the switch the owner noticed that enquiries had roughly halved. Nothing was visibly broken. The old service pages — the ones that had held search positions for years — simply no longer existed at the addresses search engines and customers had saved.
That is the shape of a migration problem. The new website works. What fails is the connection between the old address and the new one, and that connection is made of redirects, DNS records, mail settings and links you published years ago in places you no longer think about.
What AI genuinely handles well in a move
It compares two structures in seconds. Migration work starts as a matching exercise: forty old addresses against thirty new ones. Give an AI tool both lists and it proposes which old page maps to which new page, and which old pages have no counterpart at all. A spreadsheet afternoon becomes a ten-minute review.
It ports content faster than anyone retypes it. Service descriptions that lived in a PDF, price lists, legal pages, three-year-old case studies — material that has to survive the move but needs to fit the new structure’s length and tone. This is repetitive work that AI does well and humans do slowly.
It drafts the unrewarding parts. Sitemap, robots rules, alt texts, cookie notice, the wording of a 404 page. None of it wins clients; all of it has to exist on the day you switch.
Where the move goes wrong
The redirect map is missing, or points everything at the homepage. Every address that had traffic, or was linked from somewhere, has to answer with a permanent redirect to the closest equivalent page. Sending all of them to the homepage tells search engines the specific page is gone and keeps nothing. A redirect to the real replacement passes on what the old address earned; a 404 throws it away.
The switch is treated as one event instead of three. The site, the domain’s DNS records and the mailboxes are separate systems that happen to share a name. Change them all in one evening and a failure leaves you guessing which layer broke. Lower the DNS time-to-live a day in advance, verify the new website on a temporary address first, then move the domain, and leave the old hosting plan alive until mail has been sent and received on the new one for a full working week.
Business e-mail is cancelled as an afterthought. On small hosting plans the mailboxes sit in the same package as the old site. Cancelling that package to save a few euros a month takes your e-mail with it — including the address printed on invoices. If the forms on the new site should also avoid the spam folder, the sending domain needs correct mail authentication records; a contact form that delivers into a spam folder looks exactly like a contact form that is broken.
Some links cannot be redirected, and someone forgot them. QR codes on vehicles and packaging, business cards, invoices, e-mail signatures, a Google Business Profile, a supplier’s website, a catalogue. Redirects only help visitors who arrive through a browser request to the old domain — so the old domain has to keep working long after the new site is live. The practical answer is to keep the old domain registered and redirected for years, not to hand it back when the project ends.
Measurement starts from zero. A fresh analytics property with no history cannot tell you whether a dip in traffic is seasonal or damage you caused last Tuesday. Without the old data as a baseline, you lose the ability to judge your own migration.
How to run the switch without losing what the old site earned
Collect the evidence before anything is built. Export the old sitemap and, if you have access, twelve months of search data: which pages got impressions, which queries brought people, which addresses other sites link to. This list is the definition of what must not be lost, and it is the input AI needs to draft anything useful.
Turn that list into a redirect table with three columns. Old address, new address or “no equivalent”, and a short reason. AI can produce the first version; a person has to confirm the handful of pages that actually bring enquiries, because those are the ones where a wrong mapping costs money.
Rescue the material that only exists on the old site. Original photographs without a stock source, downloadable price lists, warranty documents, customer references. If the old site is switched off before these are copied, they are usually gone for good.
Separate the three switches and name one owner for each. Website, DNS, e-mail. Each can be tested on its own, and each should have a specific person who confirms it works before the next one starts. This is the difference between a planned move and an evening of improvisation.
Keep the old domain and the old mailbox plan longer than feels necessary. Years for the domain, one working week at minimum for mail. Printed material has a longer memory than any project plan.
Watch the first month deliberately. Submit the new sitemap, check that pages are being indexed, fix redirects that turned out wrong, and compare enquiries week by week against the same weeks last year. Migration problems are cheap to fix in week one and expensive in month six.
Why we plan the move together with the build
We use AI tools because they shorten the distance between an idea and a working page, and the same tools shorten the migration: comparing two structures, porting existing content, drafting the redirect table. What no tool does is take responsibility for the consequences. Nobody at a software company notices that the QR code on your van now leads to an error page, or that quote requests stopped arriving because a mail record was never copied over.
That is why the move belongs in the same plan as the website. Before the first new page is written, we list what exists today, what has to survive, and who flips each switch. A website that looks finished in an afternoon can still cost you two years of accumulated visibility if the twenty lines of redirects and records behind it are treated as a detail.
Related service: Web design and content strategy