Kevin Zambrano

Klanbarz needed to charge through PayPhone, the digital wallet most people in Ecuador actually use. Their native flow required us to host a callback endpoint — and we had nowhere to host one.

I designed an alternative around temporary payment links: the app generates a transaction id on the device, opens the gateway in the browser, and when the Android lifecycle tells me the user has come back, it queries the transaction status directly. I got the real integration documentation by reaching out to PayPhone's own engineering team, because the public docs weren't enough.

Six biometric readers, installed in locations kilometres apart, had to converge into a single operator window running on a modest machine. I built the desktop application and coordinated the REST API it depended on with the engineering team at Lartizco, over several working sessions, while their backend was still being built.

Along the way I had to solve timezone drift between sites and memory pressure on low-spec hardware. But the part I'm proudest of is what we did about synchronisation failures: I implemented per-reader log recovery so no attendance record is ever lost when a site drops off the network.

A directory that connects people with local professionals. I built and shipped the whole thing: the Flutter app, the FastAPI backend, the PostgreSQL database, the Ubuntu server it runs on with PM2, the Cloudflare layer in front of it, and the website.

I chose Flutter so one codebase could serve both platforms, and wrote the API myself so the app and the data model could evolve together instead of negotiating across a boundary.

I built Klanbarz natively on both Android and iOS, then took part in migrating it to Flutter so the product could reach more businesses from a single codebase.

When clients asked for training rankings, I built the trainer module in Avalonia — a desktop app running on Windows, macOS and Linux where coaches send group or individual workouts and follow their members' metrics.

A small arcade game, built entirely by me in two weeks — mechanics, feel, and all the way through store submission. Mostly to find out how much of a game I could finish alone, start to finish.

Twitch Hover Chat came from not having a second monitor: an overlay that keeps chat visible on top of the game without swallowing clicks. More Mur Mur does local speech recognition and turns what you say into animated, voiced dialogue lines.