Dominios y entornos personalizados

Your app is live at my-app.vercel.app — great start! But to look professional, you want your own name, like myapp.com.

You also need a safe place to store secret settings (like API keys) without putting them in your code. That's what environments are for.

This lesson covers both: custom domains and environment variables — two finishing touches that make your app feel real.

A domain is the human-friendly name people type to reach your app, like google.com or myapp.com.

The free .vercel.app or .netlify.app address works perfectly — but a custom domain:

• Looks more trustworthy and professional.
• Is easier to remember and share.
• Makes your project feel like a real product.

You buy a domain once (often $10–15/year) from a registrar like Namecheap, GoDaddy, or directly through Vercel.

Once you own a domain, connecting it is just a few clicks:

• In Vercel or Netlify, open your project's Domains settings.
• Type your domain (e.g. myapp.com) and add it.
• The host shows you DNS records to set at your registrar.
• Save those records, wait a few minutes, and your domain goes live.

If buying through Vercel itself, this is even simpler — it's all connected automatically.

DNS (Domain Name System) is like the internet's phone book — it maps your domain name to your app's host. It can look intimidating, but you rarely touch it directly.

The host tells you exactly which records to add. If anything looks confusing, paste it to AI and let it translate the steps into plain actions.

You may have noticed the padlock icon in your browser's address bar. That's HTTPS — it encrypts traffic so data is safe.

In the past, setting this up was painful. Today, Vercel and Netlify add HTTPS automatically to every domain, including custom ones, for free.

You don't configure anything. Your myapp.com will get the secure padlock on its own. One less thing to worry about.

An environment is a context your app runs in, with its own settings. Most apps have two:

• Development: on your laptop, while you build and test.
• Production: the live version real users see.

Why separate them? You might use a test database while building and the real one in production. Keeping them apart means experiments never break the live app.

An environment variable is a named setting your app reads at runtime — instead of hard-coding a value, you store it outside the code.

Common examples: API keys, database URLs, feature flags. In JavaScript, you read them like this:

Imagine pasting your secret API key right into your code, then pushing it to GitHub. Now anyone who sees your repo has your key — they could run up huge bills or steal data.

Environment variables solve this. The secret lives in your host's settings, never in the code. Your repo stays safe to share.

• Bad: const key = "sk-live-abc123..." in your code.
• Good: const key = process.env.API_KEY with the value stored on the host.

Both Vercel and Netlify have a simple panel for this:

• Open your project's Settings → Environment Variables.
• Add a name (like API_KEY) and its value.
• Choose which environment it applies to (production, preview, development).
• Save — then redeploy so the app picks it up.

Now your code reads process.env.API_KEY and the host fills in the real secret at runtime. Safe and clean.

Domains and environment variables are exactly the kind of setup where AI shines. Describe your situation and let it produce a checklist tailored to you.

While building on your laptop, you store the same variables in a special file called .env. It sits in your project but is never pushed to GitHub.

A .env file looks like this:

• API_KEY=sk-test-12345
• API_URL=https://api.example.com

Crucially, you add .env to a file called .gitignore so Git skips it. Ask AI: "Add a .env file and make sure Git ignores it." The local file feeds development; the host's panel feeds production.

Domains and secrets — two pro touches. Let's confirm the key idea.

Your app now feels like a real product:

• A custom domain replaces the default link — just add it and set DNS records.
• HTTPS (the secure padlock) is added free and automatically.
• Environments separate development from production.
• Environment variables keep secrets out of your code — set them on the host and in a git-ignored .env locally.
• AI can generate a tailored setup checklist for all of it.

Next: shipping updates to your live app safely, without breaking things.