Peter S.

I’m a Fractional CTO and Senior Software Architect with 15+ years of experience building production-grade Node.js and TypeScript systems—especially B2B SaaS platforms where correctness, integrations, and long-term maintainability truly matter. As the founder of Clever Goat, I currently deliver full-stack engineering across SaaS, CRM, and mobile applications. Before that, I architected and built a digital tax compliance platform (Connectax) at my other company, Vilkrig, which has been running in production for over 4 years—integrating with Hungary’s national tax authority (NAV) as well as the two largest Hungarian invoicing APIs (Billingo and Számlázz.hu). It’s the kind of system where a single bug can trigger audit letters, so I’m comfortable operating in domains where edge cases and data correctness carry real financial and legal consequences. ━━━━━━━━━━━━━━━━━━━━━ WHAT I DELIVER ━━━━━━━━━━━━━━━━━━━━━ ▸ Backend & API architecture (Node.js / NestJS / TypeScript / PostgreSQL) • Clean, testable REST APIs and service layers • Multi-tenant SaaS with tenant-safe filtering, RBAC, and row-level security • Background jobs, webhooks, retries, and observability • Third-party integrations: Stripe, OAuth, tax/invoicing APIs, ERP systems ▸ Legacy modernization & TypeScript migration If you have a legacy JavaScript codebase and need to modernize — gradual TS migration, dependency upgrades, CI/CD tightening, test coverage — I've done this on production systems without breaking anything. You get a migration plan, measurable weekly progress, and a maintainable codebase at the end. ▸ Architecture review & Fractional CTO consulting Fixed-scope codebase audits with a written report: what's working, what's risky, what to prioritize. Ideal if you're preparing for scale, a funding round, or a handover. I can also stay on as a fractional CTO / technical advisor for early-stage teams — 2-5 hours per week is usually enough to keep your technical direction sharp. ━━━━━━━━━━━━━━━━━━━━━ SELECTED WORK ━━━━━━━━━━━━━━━━━━━━━ * Digital tax compliance platform — Architected and built at my previous company. In production for 4+ years, with real-time integrations to Hungary’s national tax authority (NAV) and two major invoicing APIs. Multi-tenant Node.js + PostgreSQL backend processing ~X invoices/day across Y business tenants. * Clever Goat — Founder and lead engineer. Delivering custom B2B SaaS, CRM systems, and mobile applications. * LINDABI — CRM platform for construction companies, with tailored workflows for project and client management. * LINDABI Tracking — Cross-platform mobile app for workforce time tracking, specifically designed for construction site operations. * Upwork projects — Built a Node.js-based rule engine with Dockerized deployment, refactored a large React codebase, and led a full JavaScript → TypeScript migration. ━━━━━━━━━━━━━━━━━━━━━ HOW I WORK ━━━━━━━━━━━━━━━━━━━━━ - Quick discovery call → written scope with fixed milestones - Weekly demos, measurable progress, no surprises - Proper handover: documentation, deployment notes, maintainable code ━━━━━━━━━━━━━━━━━━━━━ A GOOD FIT IF... ━━━━━━━━━━━━━━━━━━━━━ You're past MVP and need a senior architect to ship real B2B SaaS — especially systems where integrations, authorization, or domain complexity make a junior-heavy team risky. If you're looking for the cheapest developer, I'm not that — but if you want something built right the first time, let's talk.