How I Built a Finance SaaS in 28 Days as a Solo Founder

From Idea to Production in 28 Days

On April 28, 2026, I had an idea. On May 25, 2026, FreeLedger was live in production with real users.

Here's the complete, unfiltered story of how I built a finance SaaS as a solo founder — including the mistakes, the costs, and what I'd do differently.

The Idea

I was researching the freelancer market and noticed something: every finance app is built for either companies or salaried employees. QuickBooks charges $30/month and has features no solo freelancer needs. YNAB is great for budgeting but doesn't understand irregular income. Wave is free but only works in the US and Canada.

None of them answer the freelancer's core question: "After taxes and expenses, how much money is actually mine?"

That gap became FreeLedger.

The Stack

I chose tools that were free to start and could scale later:

Tool	Purpose	Cost
Next.js 16	Frontend + backend	Free
Supabase	Database + auth	Free tier
Tailwind + shadcn/ui	Styling	Free
Recharts	Dashboard charts	Free
Vercel	Hosting	Free tier
Resend	Transactional email	Free tier
LemonSqueezy	Payments	5% per transaction
Namecheap	Domain (freeledger.dev)	$12/year

Total monthly cost: ~$1

The Timeline

Week 1: Foundation

Day 1: Bought domain, created accounts (GitHub, Vercel, Supabase)
Day 2: Next.js setup + landing page with waitlist
Day 3: Authentication (email + Google OAuth)
Day 4: Database schema + CRUD for clients, income, expenses

Week 2: Core Features

Day 5: Real Money Dashboard with charts (the main feature)
Day 6: CSV export + advanced filters + dark/light mode
Day 7: Polish — SEO, OG images, legal pages, loading states

Week 3: Monetization

Day 8: Free tier limits + upgrade flow
Day 9: LemonSqueezy integration (payments)
Day 10: Email notifications with Resend

Week 4: Launch Prep

Days 11-14: Testing, bug fixes, content creation
Day 15: Product Hunt launch

The Costs

Total money spent in 28 days:

Domain: $12
Hosting/DB/Email: $0 (free tiers)
Design: $0 (shadcn/ui + Tailwind)
Marketing: $0 (organic only)
Payment processing: $0 (no sales yet)
Total: $12

Total time invested: ~60 hours over 28 days (~2 hours/day average).

The Mistakes

Mistake 1: Product Hunt Expectations

I expected Product Hunt to be a game-changer. I finished at #205 with a handful of upvotes. The lesson: PH is one channel, and for a B2C product targeting freelancers, it's probably not the best one.

Mistake 2: Building Before Validating

I spent 28 days building before getting real feedback from freelancers. In hindsight, I should have spent the first week talking to 20 freelancers about their financial pain points, then built based on what they told me.

Mistake 3: Overcomplicating the MVP

The dashboard has charts, filters, sorting, keyboard shortcuts, dark mode. Most of these could have waited. The MVP should have been even simpler: just the four numbers (income, expenses, tax reserve, real money).

The Lessons

1. Free tiers are incredibly generous in 2026

You can build and launch a full SaaS for literally $12. The tools available today are mind-blowing.

2. SEO beats launches

A blog post that ranks on Google brings you traffic every single day. A Product Hunt launch brings traffic for 24 hours. Write blog posts.

3. Communities beat marketing

Genuine participation in Facebook groups and Reddit communities generates more signups than any marketing tactic.

4. Ship fast, iterate faster

28 days from idea to launch. Some features aren't perfect. That's okay. Real user feedback is worth more than another week of polish.

What's Next

FreeLedger is live and growing. The roadmap includes:

Bank syncing (auto-import transactions)
Receipt scanning with AI
Mobile app (Flutter)
Multi-currency support
Weekly email reports

If you're a freelancer and you want to know your real money, give it a try. It's free.

Try FreeLedger →

And if you're thinking about building your own SaaS — just start. The tools are free, the knowledge is accessible, and the worst that happens is you learn a ton.