SOC 2 certified
I set up the controls, audit logging, encryption and policies that took Lynx Educate through SOC 2.
Selected work across healthcare, marketplaces, fintech and SaaS. I take products from the early build to live systems with users, payments and real traffic.
Security, teams, payments and search. The parts that had to work outside the demo.
I set up the controls, audit logging, encryption and policies that took Lynx Educate through SOC 2.
I owned the stack as first engineer at Collaborate Healthcare, then grew and led the team.
I shipped DRAFA's payment flow end-to-end across the Rails API and mobile app.
I built search and assistant flows over a large pharmaceutical document set for HTA-Hive.
Teams of different sizes, real ownership and products that had to survive contact with users.
Co-Founder & Senior Ruby on Rails Engineer
I built and launched a digital health product for chronic care workflows as first engineer. I grew the team to six and led the React Native mobile apps.
Team Lead & Senior Ruby on Rails Developer
I lead engineering for a real estate marketplace, owning architecture and day-to-day delivery.
Fractional CTO & Founding Engineer
I co-founded the engineering for a staff-training platform. I led the Rails and Hotwire work, then set up the access controls, audit logging and policies that took the product through SOC 2.
Senior Full-Stack & AI Engineer · Project-based
I built AI and RAG features for an HTA research platform across Rails, Angular, FastAPI services and a SQL Gateway API.
Fractional CTO & Full-Stack Developer
I shipped a sports venue booking product end-to-end across a Rails API and React Native app, with real-time scheduling and Stripe payments.
Ruby on Rails Developer
I delivered workflow automation that reduced manual internal processes and added granular role-based access control.
Ruby Developer · Contract
I joined on a short contract to help scale a high-traffic API ahead of a major seasonal peak.
Web Developer
I started with student and client work before Rails became my main stack: WordPress, Joomla, HTML, CSS, JavaScript and PHP.
Small products are how I try ideas, learn new tools and keep shipping.
Automated Bitcoin DCA on Binance with restricted API keys, execution history and simulations.
dcaloop.com ↗
AI practice for high-stakes conversations.
pressuretalks.com ↗
A calmer way to discover scientific papers worth reading.
dailyacademia.com ↗
Hotel invoicing software built around the day-to-day work.
hoteldata.gr ↗
Shared movie discovery for groups that cannot pick what to watch.
couchpotatoes.tsirko.com ↗
A cross-platform astronomy quiz that started as a mobile development experiment.
astroquiz.tsirko.com ↗I work with teams of every size that need backend, mobile, product thinking and practical AI work to reach production.
John's AI