Roman Khrystynych

Lead Software Engineer @Rangle.Io

Toronto, ON, CA

B2B SaaS platform (DesignDrive) for interior design firms. Shipped 100+ PRs as lead engineer on a 3-person team- Architected a double-entry bookkeeping system with journal entries, chart of accounts, trial balance, and GL analysis in Next.js and Supabase- Built AP/AR modules with aging dashboards, invoice registry, vendor/client payment tracking, and retainer credit pool management- Developed tax reporting system with period validation, audit trails, and decimal.js precision for compliance requirements- Implemented account reconciliation, cash position dashboard, and expense analytics with multi-line GL allocation- Led legacy FileMaker data migration using Bun TypeScript ETL pipelines with deterministic UUID generation and batch savepoints- Designed multi-tenant RLS policies with composite indexes; optimized N+1 queries using computed views and batch loading- Established frontend patterns (SSR + infinite scroll, URL-based filters) and added Playwright E2E tests for critical flows.