Hey — quick reply, because I think you might be reaching for a co-founder to solve a problem you can largely solve with the right tooling and the right brief. Replit is more capable than most people realize, but it also has real limits. Knowing both is what makes the difference.
What Replit can do for you (most of your list, actually):
React Native for iOS and Android — yes, via Expo. Full mobile apps, not just web.
Node.js or Python backend — yes, either one, with a real server.
PostgreSQL — yes, built in. You get a managed database without setting anything up.
AI integration (OpenAI / LangGraph style) — yes, through built-in integrations, so you don’t have to wire up API keys by hand.
Auth, payments, file storage, email — yes, these exist as first-class integrations.
Hosting + deployment — yes. It builds, hosts, gives you HTTPS and a domain. You don’t need a separate DevOps step.
The AI coding tool — that’s the Replit Agent itself. It reads your whole project, writes code, fixes bugs, and explains things in plain language.
So “React Native + Node/Python + Postgres + an LLM + AI coding tool” is squarely in what Replit does well today.
What Replit can’t do for you (be honest with yourself here):
It won’t replace product judgment. It builds what you ask for. If your spec is vague, you get vague results. The thinking is still yours.
It won’t handle the hard parts of your domain for free. An app for high school minors with mental health features carries real legal and safety weight — student data privacy (FERPA/COPPA territory in the US), crisis-escalation handling, clinical disclaimers, content safety. A tool can build the features; it can’t take responsibility for getting compliance and duty-of-care right. That’s where a human expert (or a lawyer/clinician advisor) genuinely matters — more than a coding co-founder, honestly.
Real-time: Firebase isn’t native to Replit, but real-time features can be done (websockets, or you connect an external service). Just know it’s a choice, not a default.
Deeply novel or performance-critical engineering can still need a specialist. Most consumer MVPs don’t hit that wall early.
It won’t test your product with real users for you. That’s on you.
How to write a spec the Agent can actually execute well — this is the real unlock:
Don’t dump everything at once. Build feature by feature. Start with the smallest version that works (e.g. “auth + one study session flow”), get it working, then add the next piece.
Define your data model explicitly. List the main entities and how they relate (e.g. Student, StudyPlan, CheckIn, CareerGoal — and which belongs to which). The Agent builds far better when the data shape is clear.
Write user stories, not features in the abstract. “As a student, I can log a daily mood check-in and see a 7-day trend” beats “mental health module.”
Describe each screen and what it does — what’s on it, what the buttons do, what happens after.
Name your integrations up front — which LLM, which auth method, payments yes/no. Removes guesswork.
Give acceptance criteria. “Done means: a student can sign up, complete onboarding, and see their dashboard.” That tells the Agent when it’s actually finished.
Provide examples and edge cases — sample data, what happens when a field is empty, what an error should look like.
Add design direction — a vibe, colors, a reference app. It shapes the whole result.
Iterate in plain language. When something’s off, describe what you expected vs. what you got. You don’t need code vocabulary.
Short version: the stack you listed is well within reach for a solo non-technical founder on Replit. Spend your energy on a sharp, incremental spec and on the domain-specific responsibilities a tool can’t own — that’s a better use of your time than trading equity for code.
Good luck with the YC application.