Full-stack engineer — .NET, Angular, Next.js. Based in Chicago.

Seven years building systems that have to talk to each other and can't afford to be wrong. Most of my work sits where two things meet: an API and a legacy database, a web app and a piece of factory equipment, a modern front end and a protocol from 1985. That's the part most people would rather not do, and it's the part I'm good at.

I've shipped in four domains, and the constraint is what changes — not the craft:

freight-dispatch-board · .NET 8 · Angular · real-time state machine · file-drop integration A complete document lifecycle over a watched directory: a tender arrives, an acknowledgment goes back within seconds, the load is worked across multiple stops emitting status messages at each, and an invoice closes it out. Every generated document is re-parsed by an independent process to prove it's valid, and the human view sits beside the wire format on screen.

edi-x12-toolkit · C# · netstandard2.0 + net8.0 · dotnet CLI A parser and validator for a fixed-width-then-delimited binary-ish text format where the delimiters are declared inside the first segment that uses them. Zero dependencies, 64 tests, and a CLI whose every documented transcript is regression-tested against the real binary.

Same command, two files — one delimited with * and ~, the other with | and newlines. Both read correctly, because the delimiters come out of the ISA segment rather than an assumption.

fmcsa-carrier-check · Next.js 15 · React 19 · TypeScript Server-side API integration with real failure handling — including an upstream that returns 404 for "bad credential" and 404 for "not found", which most clients get wrong. 103 tests.

A carrier name typed into the box is rejected before any request goes out; a USDOT number then returns authority, insurance filings, safety rating and 24 months of inspections. Recorded against the repository's fixture payload, which the page labels on screen throughout.

opc-ua-monitor · .NET 8 · SignalR · Angular · OPC UA Live monitoring for industrial equipment — a service subscribes to node changes on an OPC UA server and streams them to a dashboard that plots them in real time. It states the browser↔API and API↔equipment links separately, because they fail for different reasons: on connection loss the last values are held and visibly labelled as held, rather than shown as though they were current.

ECommerce-Restaurant · .NET · microservices · Docker Four services, Redis-backed basket, two EF Core databases, Serilog to Seq, behind nginx, with an Angular front end. The whole stack comes up under Compose.

Demo GIF — an order placed in the storefront, then the same order arriving on the admin order-events page with the bus latency for each message.

Playbook · .NET · Puppeteer · MongoDB A resilient scraping pipeline — 16 sources, layered selector fallbacks, idempotent writes, and a retry budget, because the sites change without warning and the job still has to finish.

A real run: 16 leagues seeded from JSON into an empty MongoDB, a league and season chosen at the prompt, 30 matches found on the page, the 19 fixtures that have not been played rejected from their header alone, and the 11 finished matches parsed and written. Six minutes of running time, time-compressed.

Backend C# · .NET 6/7/8 · ASP.NET Core · EF Core · Node.js · REST · SignalR · RabbitMQ Frontend Angular · TypeScript · RxJS · React · Next.js · SCSS Data SQL Server · T-SQL · PostgreSQL · MongoDB · Redis Platform Azure · Docker · CI/CD · OPC UA · EDI X12 · DICOM/HL7

Full-time or contract — .NET, Angular, Next.js. Remote or Chicago area. Corp-to-corp available through DIS IT LLC (Illinois).

📧 yshchehliuk@gmail.com · 💼 LinkedIn · 🌐 disit.tech