New User Signup Notification: Get Emailed on Each Sign-Up

In the early days, every sign-up matters. A new user signup notification puts each one in your inbox the moment it happens, so you can see who’s arriving, say hello while they’re still exploring, and notice fast if sign-ups stop.

This guide is for founders building a SaaS, site or tool with Claude Code who want that ping. You’ll get the message to send Claude Code, a sample notification, the details worth including, and a plan for when one email per sign-up becomes too many.

Why do founders want a new user signup notification?

A sign-up notification tells you, right away, that a real person has joined. That’s good for morale, and it’s useful too:

• You can reach out while they’re curious. A short note from the founder in the first hour is a chance to ask why they signed up and what they hoped to find.
• You notice when something breaks. If you post about your launch and no notifications arrive, your sign-up form may have a problem.
• You learn who you attract. Plans chosen, company names and where people heard about you show which channels work.

It’s a transactional email: an automatic email your product sends because something happened. This one goes to you rather than your users. It’s one of many email notifications you can set up with Claude Code, and a good first test that your email setup works. For the full list of emails a SaaS usually sends, see our guide to transactional emails every SaaS needs.

What do you need before you start?

Your project can’t send email on its own. It needs an email service, connected to Claude Code through a connector (a link that lets Claude Code use another service while you build). SimpleSends connects using MCP, a standard way for AI tools to work with other services.

1. Sign up on the SimpleSends website and follow the steps there to set up the email address you’ll send from. To send from your own domain, this includes adding a few DNS records where your domain is registered.
2. In Claude Code, open Customize, then Connectors, choose Add, then Add custom connector. Name: SimpleSends. MCP server URL: https://mcp.simplesends.com/mcp
3. When Claude prompts you to connect, log in to SimpleSends.
4. Back in the Claude Code chat, tell Claude Code: "I’ve connected SimpleSends for all transactional email." It takes it from there, including adding what your project needs to send email.

If you get stuck on step 2, our guide to connecting an MCP server to Claude Code walks through each screen.

What should you tell Claude Code?

Describe what you want the way you’d brief a person: who gets the email, when it goes out, and what’s in it.

Every time someone creates an account, send me a short notification email at hello@yourcompany.com. Include their name, email address, the plan they picked, the time they signed up and how they found us, if we record that. Start the subject line with "New sign-up" so I can filter these in my inbox, and set the reply-to as their address so I can write back directly. Don’t change anything the new user sees. Send me a test first so I can check it.

Claude Code finds the place in your project where new accounts are created, adds the notification there, writes the email and sends a test to your inbox. Once your project is live, each real sign-up sends the notification straight from your project through SimpleSends. Claude Code doesn’t need to be open.

Check it works

Sign up on your own site with a test account and watch for the email. If nothing arrives, ask Claude Code. It can read your SimpleSends send logs and tell you what happened.

I signed up with a test account a few minutes ago but didn’t get a notification. Can you check whether it was sent and tell me what went wrong?

For a fuller pre-launch routine, see how to test your emails before your users see them.

Which details should the notification include?

Include enough to know who signed up and whether to act, and nothing more. Your inbox becomes one more place customer details are stored, so leave out anything you won’t use.

Here’s what a notification built from that brief could look like:

SubjectNew sign-up: Maya Patel (Pro trial)

Maya Patel created an account a moment ago.

Email: maya@yourcompany.com Plan: Pro trial (14 days) Signed up: Monday, October 5, 9:42 a.m. Found you through: a friend’s recommendation

That’s sign-up number 3 today. Reply to this email to write to Maya directly.

When should you switch to a daily summary?

Switch when the notifications stop being useful: you no longer act on each one, or you’ve started filtering them out of sight. There’s no set number. It depends on how much time you spend with each new user.

A daily summary replaces many emails with one. You can also keep instant notifications for the sign-ups you care most about.

I’m getting too many sign-up notifications. Replace them with one summary email each morning at 8 a.m. my time, listing yesterday’s new sign-ups with their name, plan and sign-up time, plus the total. Keep sending me an instant email for anyone who picks the Business plan.

Claude Code sets up a scheduled email in your project and sends you a test summary so you can check the layout. If you later want to send your users a regular digest of their own activity, the same approach works for a weekly summary email.

While you’re here, consider the other side of the sign-up: a greeting for the new person. See how to send a welcome email when someone signs up.