How I Built Fitgen: From React UI to Paying Users

Trip One — Mon, 14 Jul 2025 21:38:58 +0000

When I launched Fitgen AI generative workout builder for budget-gym rookies, I knew I needed to ship fast and smart. Here’s a peek under the hood:

🛠️ Tech Stack

Frontend: Built with React, offering a dynamic interface where users customize workout preferences, available equipment, and training goals.

Backend & Auth: Powered by Supabase (Postgres + Auth), which gives me real-time updates when users log workouts or adjust settings—zero server headache.

UI Library: Leveraged Lovable to accelerate frontend components—modals, tabs, forms—so I could focus on workout logic instead of styling every button.

Payments: Integrated Stripe for smooth subscription flow. Users can go pro in minutes after a simple checkout.

Hosting & CI/CD: Deployed on Vercel—push to main, get live in seconds. Hassle‑free from dev to production.

📈 Early Stage Metrics

This is Day 60 of public beta, deployed via a lean indie‑hacker strategy:

🚀 630 sign-ups organically from Twitter and Indie Hackers

💪 78 users upgraded to paid (“Pro”) in first month

💶 MRR ≈ €1,560

🔄 30% pay conversion among active users

🏋️ 1,200 workouts logged—users are already training consistently

For a side‑project by a solo founder, these numbers aren’t just metrics—they’re signals that Fitgen is solving a real problem.

🧠 Indie‑Hacker Strategy

Start small, launch fast
I skipped over-engineering. Instead, React + Supabase + Lovable got me to MVP in weeks.

Share wins and roadblocks
Tweeting real-time updates—user onboarding flow working, hitting €1k MRR—helped build credibility and traction.

Listen and iterate
Inside the dashboard, I added user feedback prompts: “What feature would help you next?” That drove feature sprints—circuit timer, personalized rest intervals, exportable routines.

Convert at checkout
A friction-free Stripe flow + simple Pro plan pricing = 30% conversion rate on active users—a healthy signal at this stage. Webhooks keep payment status in sync with Supabase.

🧭 What’s Next?

Refine workouts: Add AI‑generated progression plans.

Community sharing: Let users publish workouts publicly.

Affiliate partnerships: Connect gyms and equipment brands to users.

Growth loops: Referral bonuses and shareable workout links.

📝 TL;DR

Fitgen is a lean, React‑powered fitness tool aimed at self‑training beginners. With a real backend (Supabase), real payments (Stripe), and easy deployment (Vercel), I’ve validated demand: hundreds of sign-ups, dozens of paying users, and thousands of workouts logged. And I did it all in weeks, not months.

If you’re building a side‑project, ship fast. Build in public. Iterate based on real user feedback. And you might just find rocket fuel in the basics.

👋 Join my journey