In the absence sector I've worked on import and export integrations for an absence-reporting system: the pipeline through which sickness reports, recovery reports, and related case files travel between employers, occupational health services, and the central application. On the surface unspectacular work, but in practice the backbone of a process where missed deadlines have direct legal and financial consequences.
Absence software sits at the intersection of HR, healthcare, and labor law. Employers, employees, occupational physicians, and case managers all work in the same file — with very different permissions, responsibilities, and privacy levels. What a doctor may see, a manager absolutely may not, and the software must make that impossible rather than merely discourage it.
With integrations, it's rarely about one hard transformation and almost always about the sum of unusual input, missing validation, and assumptions that once held but no longer do. My approach is therefore first to make what happens inside the pipeline visible — logging, error messages that actually help operations move forward, small tooling to investigate suspicious messages — and only then to tackle bugs structurally.
Beyond firefighting, in this domain I've gained a lot of value from sharpening agreements with external parties. Many issues landed with the service desk because failure scenarios had no owner or contracts were too implicit. Tightening those agreements structurally lowered the inflow of support tickets — more an organisational than a technical win, but no less valuable.
Substantively the Dutch Wet verbetering poortwachter plays a major role: a process full of mandatory steps, deadlines, and reports that costs money the moment it's violated. Software supporting it must be strict where it has to be and lenient where it can be, and that distinction is often surprisingly subtle.
What's beautiful about absence software is that good engineering here directly contributes to people's return-to-work journey. A smooth tool means less administration for both employer and employee, and more attention for what actually matters: recovery.