Building SaaS as a Solo Founder: Full-Stack Decisions That Matter

# Building SaaS as a Solo Founder: Full-Stack Decisions That Matter As a solo founder, every decision compounds. You can't hire someone to handle the frontend while you focus on backend. You can't wait for consensus on architecture. You have to move fast, make decisions based on what users actually need, and iterate constantly. Over the past few years building BetterCapital (real estate accounting) and OfferPro (AI-powered offer management), I've learned what actually matters when you're building everything yourself. ## Architecture Decisions That Stuck The best decision I made was choosing a full-stack JavaScript stack early: Next.js for frontend + API routes, PostgreSQL for data, and keeping complexity minimal. Why? Because I needed to ship features fast. I didn't want to maintain three separate codebases. I could move a feature from frontend → backend → database and back again without context switching languages. The worst decision was overengineering early. I spent time building abstractions I didn't need yet. As a solo founder, your constraint is time, not architectural elegance. ## What Users Actually Care About When I launched BetterCapital, I thought investors wanted sophisticated reporting. They wanted to import data from their bank accounts. That's it. With OfferPro, I thought the web interface was the main product. The real insight was: agents don't want to leave their email. No-login offer submission that works with existing workflows was the game-changer. Spend time with users. Launch incomplete. Iterate on what they actually use, not what you predicted they'd need. ## The Full-Stack Reality As a solo founder doing full-stack: - You'll ship a database migration that breaks the API - You'll spend a day debugging CSS alignment - You'll realize your user auth flow has a security issue three months in - You'll refactor the same system twice because your first architecture choice was wrong This is fine. It's actually faster than coordinating with other engineers early on. The cost is burnout if you're not careful about scope. ## What I'd Do Differently Start with what users need, not what you want to build. I would have spent more time understanding real estate workflows before building BetterCapital's data model. Choose your core complexity carefully. For me, that's the AI analysis in OfferPro and the financial calculations in BetterCapital. Everything else should be boring and simple. Hire your first engineer when you're drowning in support + features. Not when you feel like you need help architecturally. Solo founders who hand off before the product works end up with expensive code that solves problems users don't have.