Taking over a medical platform handling health data

The context

A patient monitoring platform for a practice working in integrative medicine and nutrition. It carries the patient record, appointments, conditions, treatments and medication, laboratory results, and health questionnaires filled in by patients themselves.

We did not start from a blank page: the platform existed and was running. We took over its development.

The challenge

Taking over an application that handles health data adds a layer of requirement to an already delicate exercise.

The data involved is the most sensitive there is. Conditions, treatments, test results: this is health data under the GDPR, with the reinforced protection regime that comes with it. Negligence here is not a technical incident, it is a regulatory one.

Medical data models are inherently complex. A patient has conditions, which call for indications, which map to medications, which interact with allergies and ongoing treatments. These are not tables joined at random: every relation encodes a clinical reality you have to understand before modelling it.

And you inherit other people’s decisions. Taking over code means first agreeing to live with choices you did not make — and being able to tell the ones that genuinely get in the way from the ones you merely dislike.

What we did

• A comprehension phase before any change. On an existing production codebase, the first value you deliver is breaking nothing.
• Continuous development of the platform on the existing foundation: a modular back-end, typed data access, generated API documentation.
• Hardened authentication — signed tokens, password hashing with an algorithm designed for it, session rotation.
• Dashboards for day-to-day operation: patient monitoring, indicator visualisation, status history.
• Containerised, reproducible deployment, with database backups and automated certificate renewal. On a health application, operations are part of the product — a backup you have never restored is not a backup.

The outcome

The platform has been under continuous development since 2024, with regular releases and date-based versioning.

This project illustrates what a successful takeover looks like: two years in, the question of who wrote which part no longer arises. The code became ours by virtue of maintaining it, without ever needing a rewrite to take ownership.