Email Verification for SaaS Signup Flows
Stop fake signups, disposable emails, and trial abusers before they enter your product — in under 100ms.
Why fake signups hurt more than you think
Every unverified signup creates downstream problems: failed onboarding emails, inflated free-tier usage, skewed activation metrics, and support noise from users who never intended to pay.
of B2B email addresses become invalid within 12 months
Industry estimate
Disposable emails pollute your user base
Free trial abusers create new accounts with throwaway addresses from Mailinator, YOPmail, and thousands of similar services. They get unlimited trials — you get worthless data.
Typos kill activation rates
A mistyped email at signup — "gmal.com" instead of "gmail.com" — means your activation email bounces. The user gives up. You lose a real customer.
Invalid emails inflate your bounce rate
When you send onboarding, feature updates, or invoices, invalid addresses bounce. Sustained bounce rates above 2% get your sending domain flagged by major ISPs.
Role-based emails underperform
Signups with info@, support@, or admin@ addresses almost never convert. They belong to shared inboxes with no individual ownership — activation emails get lost.
Real-time validation at the moment of signup
Mailbeam integrates into your signup endpoint or form and returns a result in under 100ms — fast enough to validate inline without slowing down the user experience.
Sub-100ms response time
Verify the email while the user is still on the signup form. No waiting spinners, no page delays.
Disposable email detection
Block 50,000+ known disposable domains. The list is updated continuously — new throwaway services are caught within hours.
Typo suggestions
When a user types "gmal.com", return the suggestion "gmail.com" and let them correct it before submitting.
Role-based email flagging
Detect info@, support@, admin@, and 30+ other role prefixes. Decide whether to reject or route differently based on your product.
Implementation
Copy-paste ready. Replace the API key and integrate with your existing flow.
import { NextRequest, NextResponse } from "next/server";
// No SDK yet — the 12-line wrapper from /docs/quickstart.
import { verifyEmail } from "@/lib/mailbeam";
export async function POST(req: NextRequest) {
const { email, password } = await req.json();
const result = await verifyEmail(email);
if (!result.valid) {
return NextResponse.json(
{
field: "email",
error: "Please enter a valid email address.",
suggestion: result.suggestion ?? null,
},
{ status: 422 }
);
}
if (result.disposable) {
return NextResponse.json(
{ field: "email", error: "Temporary email addresses are not allowed." },
{ status: 422 }
);
}
// Create user account
const user = await db.user.create({
data: { email, passwordHash: hash(password) },
});
await sendActivationEmail(user);
return NextResponse.json({ userId: user.id });
}Real-world example
Codeflow (placeholder)
Developer tools SaaS
Challenge
30% of free signups were using disposable emails to abuse the 14-day trial. Activation emails had a 12% bounce rate.
Result
After adding Mailbeam at signup, disposable signups dropped to near zero and email bounce rate fell to under 0.5%.
12% → 0.4% bounce rate
* Example based on anonymized customer data. Results may vary.
Recommended plan
Starter
Most SaaS products with under 10,000 monthly signups comfortably fit within the Starter plan. Real-time single verification is the only endpoint needed.
Frequently asked questions
How fast is the verification? Will it slow down my signup form?
Mailbeam responds in under 100ms at the 99th percentile. In practice, users never notice the verification happening — it completes before they've finished reading the success message.
Can I verify the email without rejecting the signup?
Yes. You can use the verification result to score the email (0-100) and apply your own thresholds — for example, allow role-based emails but flag them for manual review.
What if the MX check passes but the SMTP check fails?
A passing MX check means the domain can receive email. A failing SMTP means the specific mailbox may not exist. You can choose to reject (strict) or warn the user (lenient) based on your signup flow requirements.
Does Mailbeam store the emails it verifies?
No. Email addresses are not stored after verification completes. Mailbeam is GDPR-compliant and EU-hosted.
Ready to get started?
Free tier includes 1,000 verifications/month. No credit card required.