Add Authentication to Your App

Want users to sign in to your app? With itsalive.co, authentication is built in. Users enter their email, click a link, and they're logged in. No password management, no OAuth setup.

Prerequisite: Run npx itsalive in your project first. This creates an ITSALIVE.md file that teaches Claude how to use the auth APIs.

How It Works

1. User enters their email
2. We send them a magic link
3. They click the link
4. They're logged in with a session cookie

Tell Claude What You Need

Just describe the authentication behavior you want. Here are some examples:

"Add a login page to my app. Show an email input field and a
'Send Login Link' button. When they submit, send a magic link
to their email. Show a message telling them to check their inbox."

"Add login to my app. If the user isn't logged in, show a login
form. After they log in, redirect them to the dashboard page.
Show their email in the header when they're logged in."

"Make the app require login. If someone visits without being
logged in, show the login page. Once logged in, show the main
app. Add a logout button in the corner."

"Add a user profile section that shows the logged-in user's
email. Include a logout button that signs them out and returns
to the login page."

Example Apps with Authentication

"Build a personal journal app. Users need to log in first.
Once logged in, they can write journal entries with a title
and content. Each user only sees their own entries. Save
entries to the database. Add a logout button."

"Create a bookmarks app where users save links they want to
remember. Require login so each person has their own bookmarks.
Let them add a URL and title, and organize into folders.
Show their email in the header with a logout option."

"Build an expense tracker. Users log in with their email,
then can add expenses with amount, category, and date.
Show a monthly summary and total. Each user's expenses
are private to them. Include logout functionality."

What Claude Knows

When you deploy with itsalive, Claude automatically knows:

• How to trigger login: Send email to the magic link endpoint
• How to check auth: See if the user is logged in
• How to get user info: Retrieve the logged-in user's email and ID
• How to log out: Clear the user's session
• Data scoping: User data is automatically private to each user

Tips

• Describe the flow: Tell Claude what happens before and after login
• Mention the UI: Say where you want login buttons, user info, etc.
• Think about states: What does a logged-out user see vs. a logged-in user?
• Ask for polish: "Show a loading spinner while checking login status"

Next Steps

• Store user data with the database API
• Add AI features to your authenticated app
• Add a custom domain for a professional look