ESF Plus
A European Social Fund Plus programme in Baden-Württemberg, run through L-Bank, needed its funded organisations to send documents to a public authority securely.
I was its only engineer for three years, employed by ISG Institut. I did the architecture, the build, the security model and the operations. Requirements gathering with L-Bank was my employer’s process, and I built against it.
- Stage
- In production
- Handed over
- 2025
- Uploads
- 22,000+ processed, from 718 organisations
- Outcome
- My employer commercialised it for €500,000
- Security
- No reported security incident
The constraint
Someone from the funding bank has to be able to ask, in 2029, who uploaded which document in 2024 and who looked at it. That question comes years after the software is finished. The answer has to be recorded from the first upload onwards.
How it is built
The audit record is written before the document is stored, so an upload that fails halfway still leaves a trace. Extraction runs on the server, so a malformed upload never becomes the browser’s problem. Role and ownership checks live in one layer that every request passes through. PHPUnit tests are written around the permission model and the extraction path.
Trade-offs
The audit trail came first
I built the audit trail before the upload feature that needed it. The usual order is to add logging later. The cost was weeks with nothing to demonstrate, while I was asked when the upload screen would work. Because of that order, every upload in the programme has an append-only record, written before the document.
Livewire for the interface
Livewire kept me to one language and one mental model, which is why one person could finish it. The interface is chattier over the network, and on a bad connection that shows. I would keep it and measure earlier.
Built with
- Server
- Laravel and Livewire, on PHP
- Database
- MySQL