Full-Stack Developer for SaaS Startups

SaaS startups rarely get burned on the idea — they get burned on the build. The failures are predictable:

• Scope that quietly triples. "Just a login and a dashboard" becomes multi-tenant data isolation, billing edge cases, and email deliverability. None of it is optional, all of it is invisible at quote time.
• Architecture decided too early or too late. Pick the wrong multi-tenancy model and you rewrite data access months in. Defer it entirely and you ship a single-tenant app you can't sell to a second customer.
• Billing as an afterthought. Stripe is easy to demo and hard to get right: proration, failed payments, trials, webhooks that arrive out of order. This is where MVPs leak revenue or break silently.
• A build you can't maintain. No-code stalls the moment you need custom logic; a contractor who disappears leaves code nobody can read.

If you're pre-revenue and racing runway, each of these costs weeks you don't have.

Don't evaluate on framework name-drops. Evaluate on whether they've shipped the unglamorous parts of a real SaaS. Ask specifically:

• "Show me multi-tenant data isolation you've shipped." How do they keep Customer A from ever seeing Customer B's data? With Supabase that's Row-Level Security; with Firebase it's security rules. They should explain the mechanism, not just say "it's secure."
• "Walk me through your Stripe webhook handling." A good answer mentions idempotency, signature verification, and what happens when a webhook fails or fires twice. Vague answers are a tell.
• "What broke in production and how did you find out?" People who've operated software have a story. People who've only built demos don't.
• Check the live products yourself — sign up, poke the edges, see if it falls over.

I point clients at three live builds for this reason: BookBed (multi-tenant booking SaaS with bidirectional iCal sync that eliminates double-bookings, on Flutter + Firebase + Stripe), Callidus (clinic management SaaS on React + Firebase), and Pizzeria Bestek (real-time ordering on React + Supabase). Production, not prototypes — go break them.

A sane MVP is scoped tight and shipped in slices, not revealed in one big bang four months later.

1. Scope call, then a written plan. We agree on the thin v1 — the feature your first customers actually pay for — and defer the rest to a backlog. Honest cuts here protect your timeline.
2. Foundation first. Auth, tenant model, and billing wiring go in early, because they're expensive to retrofit.
3. Weekly shippable progress. You should be clicking real, deployed software every week. A developer who can't show working software weekly has a process problem.
4. Handover you can live with. Clean repo, environment docs, and the option to bring in another developer later without a rewrite.

Working solo and AI-augmented, I cut the overhead of a traditional agency — no account manager and no handoff layer between you and the person writing the code.

Timeline. A genuinely scoped SaaS MVP — auth, multi-tenancy, payments, the core workflow — is a weeks project, not a quarters one. The variable isn't speed; it's how disciplined you are about cutting v1. Wide scope turns weeks into months, whoever builds it.

Budget. Agencies commonly quote tens of thousands for the same MVP, much of it overhead. A solo full-stack developer costs a fraction of that for comparable production output. The honest trade-off: one person is key-person risk, so clean handover and readable code matter more, not less.

Red flags to walk away from:

• A fixed quote given before anyone scoped the data model or billing flows.
• "We'll figure out multi-tenancy / payments later" — those are the foundation, not polish.
• No live, operable product they've shipped end to end.
• Promising every requested feature in v1 instead of pushing back on scope.
• No plan for how you keep moving if they suddenly disappear.

With a deadline and runway burning, the right hire shows you working software in the first week and tells you which features to drop.