I built an auth backend for my own app — then tried selling it to see if it works
Source: Dev.to
Introduction
When I started working on a new Android mobile app, I knew one thing for sure: I didn’t want to rewrite authentication logic again. Auth is one of those things you must get right, but it’s also the part I enjoy the least—JWT setup, refresh tokens, expiry handling, logout, edge cases, and keeping libraries in sync.
Building a Reusable Auth Backend
For this project I decided to build the backend completely from scratch on my own, including auth, something I hadn’t owned end‑to‑end before. Instead of rushing through auth just to move on, I slowed down and treated it like a reusable backend.
Stack
- Fastify
- TypeScript
- Prisma
Implemented Features
- JWT access tokens
- Securely stored refresh tokens
- Token rotation
- Logout and revocation
- Clean validation
- A proper Postman collection to test flows
The goal was simple: if I ever start another project, I should be able to reuse this without fear.
From Experiment to Market Test
While building the backend a thought came up: if I’m learning this the hard way, maybe other developers are too. I cleaned the project, added proper environment configuration, removed generated files and secrets, and treated it like something that could be reused.
Then I asked myself a very honest question:
What if I try selling this—not to make money, but simply to see if anyone finds it useful?
No big expectations, no launch hype—just curiosity.
Lessons Learned
- Marketplaces don’t bring traffic automatically – visibility still requires effort.
- Backend templates aren’t impulse buys – developers evaluate them carefully.
- Selling dev tools is more about trust than features – credibility matters.
- Preparing something for others forces you to write cleaner code – you spot gaps you’d otherwise ignore.
Even if nobody buys it, the exercise itself was worth it.
Outcomes
- A solid auth base for my app.
- A backend I understand deeply because I built it myself.
- A clearer understanding of how developer products actually work.
I’m sharing this not to aggressively sell anything, but because most posts talk about passive income and overnight success, while few describe the real process:
- Build something for the first time.
- Learn parts you previously avoided.
- Question your own correctness.
- Put it out there anyway.
If you’ve ever avoided auth because it felt risky, or built backend pieces without fully owning them, you’re not alone. I documented what I built and shared it publicly for anyone curious. The link is available on my profile.
Closing Thought
Sometimes the goal isn’t immediate sales—it’s learning whether an idea deserves more time.