I Built a SaaS in 3 Days That Solves a $500 Problem for Free

The Problem I Kept Seeing

Every week, I'd see marketers and agencies
losing Google Ads conversion data without
knowing why.

The culprit? Consent Mode v2.

Since March 2024, Google requires proper
consent signals for EU/UK ads. Sites without
it lose:

• 20-40% of conversion tracking data
• Remarketing audiences
• Attribution accuracy

Agencies were charging $200-500 to audit
this manually. Most site owners had no idea
they were affected.

What I Built

TagIntegrity — a free Consent Mode v2
scanner that checks any website in 60 seconds.

🔗 tagintegrity.com

It checks:

• Google Tag Manager configuration
• GA4 and Google Ads detection
• Consent Mode v2 signals
• CMP (Consent Management Platform) presence

Generates a shareable report showing exactly
what's broken.

The Tech Stack

Built entirely with:

• Lovable (frontend + backend scaffolding)
• Supabase (database, auth, edge functions)
• Firecrawl (web scraping/scanning)
• Stripe (payments)
• Google AI Studio (Gemini Flash for AI-generated GTM fix guides)

Total build time: 3 days
Total cost: ~$32 (domain + Lovable Pro)

What I Learned

1. Ship ugly, then polish

My first version was embarrassingly basic.
Just a URL input and a pass/fail result.

But it worked. Real people used it.
Their feedback shaped every feature after.

2. Security takes longer than you think

I thought security would take 2 hours.
It took 2 days. Key issues I had to fix:

• Users self-upgrading their plan in Supabase
• AI feature accessible without authentication
• Email spoofing for quota bypass
• GTM fix guide readable via direct API calls

Each fix taught me something new about
Supabase RLS policies and edge function auth.

3. DNS is always the hardest part

Spent 3 days trying to connect my domain.
The issue? Wrong nameservers pointing to
an old hosting provider.

Lesson: Always check nameservers FIRST
when DNS isn't working.

4. No-code/low-code is legitimately powerful

I'm not a full-stack developer.
Using Lovable + Supabase, I built:

• Authentication system
• Payment processing
• AI integration
• Rate limiting
• RLS security policies
• Edge functions
• PDF generation

Things that would have taken weeks
took hours.

5. The "launch" is never perfect

I launched with:

• ❌ Broken shareable links
• ❌ Email delivery not working
• ❌ Missing pages (404 errors)
• ❌ Security vulnerabilities

But I launched anyway. Fixed things as
real users found them.

Current Status

• ✅ Live at tagintegrity.com
• ✅ Visitors from 8+ countries
• ✅ US, UK, France, Australia traffic
• ✅ Featured on Hacker News
• ✅ 3-tier pricing (Free/Pro/Agency)
• 🔄 Working on first paying customer

The Monetization Model

Free: 5 scans/month, basic reports
Pro ($79/mo): Unlimited scans +
AI-generated GTM fix guides
Agency ($299/mo): White-label reports,
50 client sites
Setup Service ($199): Done-for-you
implementation

What's Next

1. First paying customer (this week!)
2. Blog content for SEO
3. Agency partnerships
4. Automated email sequences

Try It

If you manage Google Ads or build sites
for clients, check your Consent Mode setup:

👉 tagintegrity.com

Takes 60 seconds. Completely free.

Example scan:
tagintegrity.com/results/347d5a06-541d-4d6c-aff8-ead2f2718ef8

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Happy to answer questions about the build,
the stack, or the business model.

What would you have built differently?