How to Validate Emails Automatically in Bolt.new and Lovable Signups Using ZeroBounce

Fake signups, disposable emails, and bad data can quietly sabotage your onboarding and email deliverability. In this step-by-step guide, you’ll learn how to integrate ZeroBounce email validation directly into your Bolt.new and Lovable apps (no-code or low-code) so you can block invalid emails, reduce fake leads, and keep your lists clean from day one.

The problem: fake signups, deliverability issues, and bad data

If you build apps with Bolt.new, Lovable, or any AI-powered builder, user signups fuel everything from onboarding and product communication to customer retention. But the truth? Not every signup is a real user.

Common issues include:

• People mistyping their email addresses
• Bots creating disposable signups
• Fake trial users polluting your database
• Spam traps and abuse addresses hurting sender reputation

ZeroBounce, Bolt.new, and Lovable each play a critical role in controlling this problem. With a real-time validation layer, you can stop low-quality data from ever entering your system.

Why ZeroBounce email validation is the missing piece

When you plug ZeroBounce email validation into your signup flow, the API instantly analyzes every address and identifies:

• Undeliverable or invalid emails
• Disposable or temporary inboxes
• Spam traps and known abuse addresses
• High-risk domains
• Everyday typos you can auto-correct

This helps any Bolt.new or Lovable-generated app maintain strong email hygiene, improve deliverability, and keep databases clean.

Try the ZeroBounce free email verifier

What you’re building

So what do you get? A smart signup flow in Bolt.new or Lovable that:

• Automatically validates every email before signup
• Suggests corrections for common typos
• Blocks disposable or suspicious emails
• Provides real-time feedback to users
• Reduces fake leads and improves onboarding quality

Step-by-step walkthrough

Step 1: Get the project ready

In Bolt.new or Lovable, create a new project or open an existing one.

Both platforms allow rapid creation of fully functional authentication flows without starting from scratch, have that ready before moving to step 2.

Step 2: Ask the agent to implement the email validation during your signups.

In your Bolt.new or Lovable chat interface, upload the following files:

– zb_migration.sql

– example_auth_form.tsx

and copy / paste the prompt:

You are my senior engineer programmer. I’m attaching two files:

zb_migration.sql 

example_auth_form.tsx

Plan

First apply the migration. Then implement a production-ready user signup flow in this repository using the attached files as the source of truth. Make minimal, idiomatic changes that fit the project’s existing stack and conventions.

Step 3: Configuration

1. bolt.new

Go to Database ? Tables ? app_secrets, and insert a new row:

name	value	updated_at
ZEROBOUNCE_API_KEY	your_api_key_from_zerobounce.net	2025-11-14 13:46:58+00

2. Lovable

Go to Cloud ? Tables ? app_secrets

name	value
ZEROBOUNCE_API_KEY	your_api_key_from_zerobounce.net

You can find your API key here

Now your backend system can securely connect to ZeroBounce’s validation API.

Try the ZeroBounce real-time email verifier

Step 4: Try the Signup Flow

Preview your app and try signing up with a few test emails:

• Typo example: jane@gmial.com ? “Did you mean jane@gmail.com?”
  
• Disposable email ? instantly rejected
  
• Valid address ? signup completes successfully
  

All of this happens in real time, using Supabase triggers and stored functions powered by the zb_migration.sql file.

Evaluate your email list for free

? Watch the Walkthrough Tutorials

Watch the complete step-by-step guides below for Bolt.new or Lovable if you get stuck with the steps:

1. Bolt video

2. Lovable video