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SaaS Signup Fraud Prevention API

SaaS signup fraud prevention starts at the form. Add one API call to your signup flow and Fidro stops disposable emails, bots and fake accounts before they reach your database, in under 200ms on average.

What is Fidro?

Fidro is a fraud detection API for developers. One call checks the email, the IP and the network, remembers what it has seen before, and tells your code to allow, challenge or block, so you stop fake signups and stolen cards without building your own scoring. The free plan covers 200 validations a month, no credit card.

The problem

Fake signups cost more than they look. They use up your free tier, open support tickets, skew every metric you report, and someone still has to find them and ban them by hand. Disposable emails sail through verification, and a script can create a hundred accounts before lunch.

How Fidro fixes it

Fidro checks the email, the IP and the network at signup, and remembers what it has seen, so the fifth signup from one IP this hour gets noticed even when each one looks clean on its own. You get allow, challenge or block before the account exists.

What you get

Disposable email detection

Spot signups from nearly 10,000 known disposable email domains, the moment they hit your form.

IP risk analysis

Catch signups from VPNs, Tor exit nodes, datacenters and known proxy networks.

Memory across signups

Send event: signup and Fidro counts signups per IP, network and email pattern, and flags bursts. On every plan.

50K+
Disposable domains
<200ms
Response time
200
Free validations/mo

Keep exploring

Try the free checkers on a real address, read every field in the docs, or see how Fidro compares.

All features API documentation Free email checker Free IP checker Compare Fidro

Frequently Asked Questions

How do I block fake signups on my SaaS?
Call Fidro from your signup handler with the email and IP. It checks for disposable domains, risky networks and repeat signups, and answers allow, challenge or block. Block the clear cases, challenge the borderline ones, and let everyone else straight in.
What is a disposable email and why should I block them?
A temporary inbox from services like Guerrilla Mail or Mailinator. People use them to abuse free tiers, create fake accounts and get past email verification. Fidro recognises over 50,000 disposable email domains.
Does Fidro work with any signup form?
Yes. Fidro is a REST API, so it works with any stack. Call /api/validate from your signup code and act on the answer: allow, challenge or block.
How much does signup fraud protection cost?
The free plan covers 200 validations a month with no credit card. Paid plans start at $29 a month for 5,000.

Start catching bad signups in the next 5 minutes

Create your account, grab your API key, and send your first request. Free plan with 200 validations/month. No credit card. Cancel anytime.

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