Localhost

Your computer’s address. A website opened at localhost runs only on your machine, not on the internet.

You’ll also find it as: localhost:3000

How it appears in the course

${DATABASE_URL:-postgres://localhost/dev} means: “use DATABASE_URL if it exists; if not, use the address after :-”.

How do you share servers with the team? · Module 08, MCP: connecting to other apps

The second: Claude opens your website from your computer (localhost = “on this computer”), goes through the checkout steps and looks for errors.

How do you use it, in practice? · Module 08, MCP: connecting to other apps

In module 08 · MCP: connecting to other apps, in the Claude Code for Beginners course.

12 modules with 1–2 minute lessons, which you can also do on your phone. The first two modules are free.