How Vercel App Works with a Domain

How to Link a Domain to a Vercel App

Vercel acts as a hosting platform that simplifies the deployment and management of web applications ^1. When you link a custom domain to your Vercel app, here's how it works behind the scenes:

1. Domain Linking and DNS Configuration:

• Adding Your Domain: You initiate the process by adding your custom domain (e.g., yourdomain.com) to your Vercel project through the project's settings dashboard.²

• DNS Instructions: Vercel then provides you with specific DNS records that you need to configure with your domain registrar (the company where you bought your domain).³ These records tell the internet where to find your Vercel app when someone types your domain name into their browser.

• Types of DNS Records:

  • A Record (for Apex Domains): For your main domain (like yourdomain.com), Vercel usually instructs you to create an A record that points to one of Vercel's IP addresses. This directly links your domain to Vercel's servers.

  • CNAME Record (for Subdomains): For subdomains (like www.yourdomain.com or blog.yourdomain.com), you'll typically create a CNAME record that points to a Vercel-provided subdomain (usually ending in .vercel.app). This tells the DNS system to look up the IP address for the Vercel subdomain.

  • Nameservers (Alternative Method): Vercel also allows you to delegate DNS management entirely to them by updating your domain's nameservers to Vercel's nameservers. If you choose this method, you manage all your DNS records directly within the Vercel dashboard.⁴

2. Verification:

• Once you've configured the DNS records with your registrar, Vercel needs to verify that you own the domain. This process usually happens automatically but can sometimes require adding a TXT record to your DNS settings for confirmation.

3. Traffic Routing:

• When a user enters your custom domain into their browser, the browser initiates a DNS lookup.

• The DNS system follows the records you configured (either the A record or the CNAME record pointing to Vercel, or the nameservers directing to Vercel's DNS) to find the IP address of Vercel's servers hosting your application.⁵

• The browser then sends a request to that IP address.⁶

4. Vercel's Edge Network:

• Vercel utilizes a global Edge Network.⁷ This means your application's files are distributed across servers located in various geographical locations.

• When a request for your domain reaches Vercel's network, it's routed to the server closest to the user, resulting in faster loading times and improved performance.

5. HTTPS/SSL:

• Vercel automatically provisions and manages SSL/TLS certificates for your custom domains through Let's Encrypt.⁸ This ensures that your website is served over HTTPS, providing a secure connection for your users. You don't need to handle certificate generation or renewal manually.

6. Deployment Association:

• When you link a domain to your Vercel project, it's associated with the latest production deployment of your application by default. You can also configure specific domains to point to different branches or deployments within your project settings.

In essence, Vercel simplifies the often complex process of connecting a domain to your web application by providing clear instructions for DNS configuration and handling the underlying infrastructure for routing traffic, ensuring security (HTTPS), and optimizing performance through its Edge Network.⁹