With this article, we plan to guide you through all the steps necessary on how to migrate a domain to Vercel without downtime. Your domain should be serving content from 3rd party servers that are unrelated to Vercel, and you need to be prepared to make the necessary DNS changes.
Generating a Certificate
While Vercel will serve your domain with HTTP until a certificate is ready, it is a good experience for your users to use HTTPS. Therefore, to ensure the certificate exists beforehand, you can generate it manually. To do so, you can use the following commands using the Vercel CLI:
vercel certs issue "*.example.com" example.com --challenge-onlyWe recommend users to issue certificates for the specific domains they want to migrate. If the DNS configuration of example.com is pointing to non-Vercel servers, and you plan to migrate both www.example.com and example.com to Vercel deployments, you can create a challenge with the following command:
vercel certs issue www.example.com example.com --challenge-onlyAfter running the command above, make sure you insert the necessary TXT records in your DNS provider. You can also check if the records are correct with the command dig:
dig TXT _acme-challenge.example.com +shortAfter the challenge is in place, we can issue the certificate. You can enter the command previously used without the --challenge-only flag:
vercel certs issue www.example.com example.com
Verifying the Certificate
We learned how to generate a certificate before we assign a domain to a Vercel deployment. Before you change the DNS records of your domain, we can verify if the certificate is correct and will be accepted by browsers. You can run the following command:
curl https://example.com --resolve example.com:443:76.76.21.21 -IIf the request is successful, we confirmed the certificate is working and you can proceed with the migration.
Changing the DNS Records
Once you have added the domain to your Vercel project and also verified the certificate is working as expected, you can choose three options of records to finally complete the migration: A, CNAME, or Nameservers. In case you decide to use an A or a CNAME record, then you can change those records in your DNS provider to make Vercel serve your deployment from the selected domain, as instructed on your dashboard.
If you decide to change the Nameservers of your domain, you can follow the below instructions which will help you migrate your DNS configuration to any provider and avoid downtime.
Clone the Current DNS Configuration
To locate the current DNS provider of your domain, you can run the following command:
dig NS example.com +shortThe result will show the current DNS authority. Next, you'll need to locate your DNS records from the provider's dashboard. If you are using Vercel, the DNS configuration is located in your dashboard.
After you've successfully located all records associated with your domain, you can either download a "zone file" or copy each record manually to the new provider.
Verify the Records
To verify the records, you can query the DNS configuration served by the future DNS authority:
dig A api.example.com +short @ns1.vercel-dns.comIf you were moving your DNS to Cloudflare, for example, the correct command would be:
dig A api.example.com +short @example.ns.cloudflare.comBefore proceeding, we recommend checking every record you moved. For more insight into the DNS resolution, remove the +short flag.
Switch the Nameservers
In your registrar's dashboard (where you bought the domain), change the Nameservers to your new provider. Nameserver changes can take up to 48 hours to propagate. If you bought the domain from Vercel you can manage nameservers from the domains page.