One student in Germany. No funding. No team. Just Next.js, Supabase, and an idea. This is the full story of building FlowFund.
I was 15 years old when I first noticed the problem. My older sister was freelancing — design work for clients across Europe — and she was using a spreadsheet to track everything. Not because she liked spreadsheets, but because every finance app she tried assumed she lived in the US, earned in one currency, and had a salary.
YNAB wanted to connect to her German bank account and couldn't. Mint was US-only. The apps that claimed to work globally were either broken or so limited they weren't worth using.
I thought: someone should build this properly. Then I thought: why not me?
I had zero experience with web development at the time. I didn't know what Next.js was. I'd written some basic Python in school. That was it.
The first three months were just learning. I built terrible things. I rewrote them. I watched YouTube tutorials at 2x speed. I asked stupid questions on Stack Overflow (and got some surprisingly helpful answers). I read Supabase docs at midnight.
The moment I realized this might actually work was the first time I connected Supabase to a Next.js frontend and saw real data appear on screen. Something that simple felt like magic.
Why Next.js 14: App Router felt like the right architecture for a dashboard-heavy application. Server components meant I could do data fetching server-side and not leak my Supabase keys.
Why Supabase: Postgres + auth + storage + real-time, all in one. For a solo developer with no DevOps experience, Supabase was the difference between shipping and not shipping. Row Level Security meant I could build multi-user data isolation without a custom backend.
Why inline styles instead of Tailwind: Tailwind is great. But for a SaaS with a complex dark theme, inline styles gave me exact control over every value. No class purging issues. No build step surprises. Direct CSS-in-JS without the JavaScript bundle cost.
Why Claude AI: I evaluated several AI APIs. Claude's ability to analyze financial data and give contextual, non-generic advice was noticeably better for this use case. The AI advisor in FlowFund reads your actual transaction data — not a generic prompt.
The security infinite recursion bug was one of the worst. I had written a Supabase RLS policy that queried a table that queried back into the first table — an infinite loop that crashed every household creation. It took 3 days to find.
The SWC compiler issue with template literal backticks in JSX style attributes caused builds to fail silently in ways that took forever to debug. I eventually wrote a one-line grep to scan for this pattern before every push.
The biggest lesson: build incrementally and test on real users early. Every bug I found in production was one I could have found in development if I had shipped sooner.
I spent 2 months building features no one asked for before I showed the product to anyone. By the time I got feedback, I had to rebuild significant portions.
I didn't set up proper error logging for the first 6 months. Bugs were happening silently that I only discovered when users mentioned them.
I underestimated mobile. The first version was desktop-only and looked broken on phones. Fixing mobile responsiveness took longer than building most features.
Launching to zero users is humbling. The first week of traffic was basically me refreshing my own analytics dashboard.
The first real user — someone I didn't know, who found the site through a Reddit post — was validating in a way I can't fully describe. Someone chose to give my product a try out of genuine interest. That still means everything.
FlowFund is live at flowfund.finance. It has:
Built by one student in Baden-Württemberg, Germany. Zero funding. No co-founder. Just code and a problem worth solving.
Bank API integration via Open Banking (PSD2 in the EU). Mobile apps. A team plan for agencies managing client finances. Public API for developers.
And more users. That's always the thing.
If you made it this far: try the demo at [flowfund.finance/demo](/demo). No signup required. Tell me what you think — genuinely. I'm reading every message.
This is only the beginning.
Free to start. No bank connection. No KYC. Works in 20+ countries.
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