Mar 29, 2026•3 min read

How Fake Signups Forced Me to Build OnSefy AI (And What Most SaaS Founders Ignore)

How Fake Signups Forced Me to Build OnSefy AI (And What Most SaaS Founders Ignore)

When you build a SaaS, you celebrate signups.

More users usually means growth… right?

That’s what I thought too.

But after running my own SaaS products, I discovered something most founders don't talk about:

Not all signups are real users.

Some are bots.
Some are trial abusers.
Some are competitors scraping data.
Some are just spam.

And they silently destroy your product metrics.

The problem I noticed

At first everything looked good:

  • Signups increasing

  • Trials increasing

  • Traffic growing

But revenue wasn't growing at the same rate.

That was the first red flag.

When I investigated deeper I found:

  • Disposable emails creating multiple trials

  • Bots creating accounts automatically

  • Fake users testing system limits

  • Spam accounts polluting dashboards

The biggest damage wasn't infrastructure cost.

It was bad decisions caused by bad data.

When fake users enter your funnel:

  • Conversion rates become inaccurate

  • CAC calculations become wrong

  • Product decisions become misleading

  • Growth experiments become unreliable

You think your product has a conversion problem.

But sometimes you have a user quality problem.

Why existing solutions didn't work

I tried:

  • CAPTCHA

  • Email verification

  • Domain blocking

  • Manual review

  • Basic fraud rules

They helped, but didn't solve the real problem.

Fraud today is not simple spam anymore.

Modern abuse includes:

  • Residential proxy IPs

  • Temporary email rotation

  • Human-like automation

  • AI-generated behavior patterns

Static rules fail because attackers constantly adapt.

The idea behind OnSefy AI

Instead of blocking users based on one rule, I wanted to measure risk signals.

The idea was simple:

Every fake user shows small warning signals. Together they form a risk pattern.

So I started building OnSefy AI around:

  • Risk scoring instead of binary blocking

  • Behavior intelligence

  • Infrastructure detection

  • Pattern recognition

  • Trust signals

The goal was not to stop signups.

The goal was to improve signup quality.

Early lessons while building

Some things I learned quickly:

Lesson 1 — False positives are worse than missed fraud
Blocking a real customer hurts more than allowing one fake signup.

Lesson 2 — Fraud prevention is a growth feature
Better users = better conversion data.

Lesson 3 — Most founders notice this too late
Usually after scaling problems appear.

Lesson 4 — Prevention is cheaper than cleanup
Stopping fake users early saves support, infra, and analytics headaches.

What we are building next

Current focus areas:

  • Real-time fake signup detection

  • Trial abuse prevention

  • SaaS risk scoring API

Next roadmap:

  • Account takeover detection

  • Promo abuse detection

  • Payment fraud signals

  • Trust scoring system

Why I'm building in public

Building in public helps with:

  • Accountability

  • Feedback

  • Learning faster

  • Meeting other founders solving similar problems

And honestly, many founders are facing this problem but few talk about it openly.

A question for other founders

I am curious:

At what stage did you first notice fake or low-quality users affecting your SaaS?

Was it early or after scaling?

Would love to learn how others are solving this.