Staff Software Engineer
Jayson Virissimo is a Staff Software Engineer at SUBSCRIBE, where he's helping build the operating system for the alternative investments industry. He works primarily in Ruby on Rails, with Postgres, React, and GraphQL across the stack. Outside of work he builds learning tools grounded in spaced repetition — most recently Altkata and LedgerLore, native apps for iPhone, iPad, and Mac. He lives in Arizona.
Native Apple apps that teach a professional field through short exercises scheduled by FSRS. Sessions end each day, a full hands-free voice mode works while walking or driving, and everything is local-first with optional iCloud sync — no accounts, no tracking.
Learn financial technology
The engineering side of fintech: double-entry ledgers, payment rails (ACH, cards, instant, wire), reconciliation, idempotency, and webhooks — ordered so no term appears before the card that defines it.
686 exercises · 53 topics
Website In App Review
Learn alternative investments
The foundations of alternative investments: private equity, hedge funds, real estate, infrastructure, commodities, structured products, and digital assets, plus the regulatory and tax frameworks around them.
1,728 exercises · 54 topics
I extracted Altkata’s engine into recito, a Swift and Ruby framework for building apps like these, and LedgerLore is built on it. (Not yet open source.)
A browser-based platform for practicing 22 classic algorithm problems by making the tests pass in JavaScript, Python, or Ruby — running Ruby and Python entirely client-side via WebAssembly (ruby.wasm and Pyodide).
An interactive tool for building digital logic from NAND gates up to a complete Arithmetic Logic Unit, following the Nand2Tetris curriculum. Write real HDL in the browser with live verification, SVG circuit diagrams, and progressive hints.
A Ruby gem that turns your ActiveRecord models into smart flashcards. Add has_deck to a model and get spaced-repetition scheduling — from the classic Leitner system to the modern FSRS algorithm.
A Ruby gem that converts Latin text into phonetic spellings and IPA lexicons so text-to-speech engines (like AWS Polly) can authentically pronounce medieval Latin.