Production systems built at Vertex Special Technologies and Ureka Systems: permission models, document pipelines, financial reporting and device integration. Most are client-owned, so the code stays private. The architecture and the decisions do not.
Written up in full: the problem, the constraints, what I decided and what it cost.
Vertex Special Technologies
Roles created at runtime, granted per module, feature and action across 325+ endpoints, with no policy registered at startup and no database query on the authorization path.
Vertex Special Technologies
OCR extraction handled by an external service that can be slow, silent or repeat itself, with live status pushed to everyone watching, credit reserved and settled against real page counts, and callbacks safe to receive twice.
Vertex Special Technologies
Ten days debugging a biometric device that stopped answering after every fingerprint scan, the decision to replace the hardware rather than keep fighting it, and the background worker that replaced it, syncing twice a day around the start and end of the working day.
Vertex Special Technologies
A request fingerprint hashed from parsed user-agent fields and the network address, a three-month window measured from last use rather than enrolment, and a clear-eyed account of why a device fingerprint is a decision about how often to ask, not a second factor.
Vertex Special Technologies
General Ledger, Trial Balance, Profit & Loss and Balance Sheet, each leaving as JSON, CSV, Excel or PDF from one pipeline: how an account hierarchy survives being flattened into formats that have no idea what nesting is, and what twelve near-duplicate renderers cost.
Shipped and in use. Not yet written up at length.
2 projectsVertex Special Technologies
A Node.js microservice running LibreOffice in Docker, shared across several .NET projects alongside a URL shortener.
Ureka Systems
Distributed .NET microservices with Kafka and Rebus messaging over RabbitMQ, Redis caching, Keycloak identity, gRPC between services and YARP routing at the edge.