Building a personal finance app used to mean begging users to paste a CSV export — or worse, to share their banking password with a screen-scraping service. Open Banking was supposed to fix that, and under PSD2 it largely has. Every regulated EU/UK bank now exposes a standard API that returns your balances and transactions as clean JSON, with your explicit consent.
So why isn't every indie developer shipping a net-worth dashboard on top of it?
Because the "official" path to those APIs requires an eIDAS qualified certificate (QWAC + QSeal), a regulator licence, and weeks of compliance paperwork. That's the wall most tutorials quietly skip. This one doesn't. We'll cover how PSD2 APIs actually work, why the certificate requirement blocks indie builders, and then build a working personal-finance tracker end-to-end using a certificate-free provider — with real curl and Python you can run today.
What an "Open Banking API" actually means
Two pieces of jargon do most of the heavy lifting, and clearing them up front will save you hours:
