How to Migrate a Website to a New Host With Zero Downtime

Why most migrations cause downtime

The classic mistake is changing your domain DNS first and copying files second. For the hours it takes DNS to propagate and your files to upload, half your visitors hit a broken or empty site. The fix is to reverse the order: get an identical copy running on the new host, verify it privately, and only then flip DNS.

Before you start: a checklist

• Full backup of your current site files and databases.
• A list of every email account on the domain, you do not want to lose mail.
• Your domain registrar login, where you change nameservers or DNS records.
• Note your current DNS TTL and lower it to 300 seconds a day before migrating.

That last point matters: TTL (time to live) tells the world how long to cache your DNS records. Lowering it to five minutes a day ahead means the eventual switch propagates in minutes, not hours.

Step 1: Build the site on the new host

Create the hosting account, upload your files and import your databases on the new server, exactly as they are on the old one. Do not change the domain yet. The new host gives you a temporary URL, or you can preview via your local hosts file, so you can load the site as if DNS already pointed there.

Step 2: Verify everything privately

Click through the previewed copy on the new host. Fix configuration (database credentials, file paths, hard-coded URLs) now, while real visitors are still served by the old host.

• Homepage and key landing pages render correctly.
• Admin login works and the dashboard loads.
• Contact and checkout forms submit successfully.
• SSL is installed so the site loads over HTTPS.

Step 3: Set up email first

Email is the part people forget. Recreate every mailbox on the new host before you switch. Losing a day of customer email is far worse than a few minutes of website downtime.

Step 4: Flip DNS

Now point your domain at the new server by updating the A record (and AAAA for IPv6) to the new IP, or by changing nameservers. Because you lowered the TTL, most visitors move over within minutes. The old and new copies are identical, so even visitors still hitting the old server during propagation see the same site.

Step 5: Keep the old host for a week

Do not cancel the old account immediately. Leave it running for about a week so slow-to-update resolvers, and any stray email, still land somewhere valid. Once your analytics show all traffic on the new server, you can safely cancel.

The Corenzy shortcut

If this sounds like a lot, it is exactly what a good host does for you. Corenzy migrates your site for free with zero downtime, regardless of your current provider, our team handles the copy, the verification and the DNS cutover.

Never change DNS first. Build the new site, verify it privately, then flip, that single rule turns a stressful migration into a non-event.