Stanislav Shtelmakh
Private message
Offer work
Dnepr,
Ukraine
available for hire
Rating
CV
I ship end-to-end SaaS for solo founders and indie operators — Stripe checkout, automated license delivery, embeddable Shadow-DOM widgets, Telegram bots and Mini Apps. One developer, one production loop, lifetime-license economics on $5 VPS.
Core Engineering Capabilities:
End-to-End SaaS Loops: Stripe → Resend → license-key delivery → domain-bound widget gating. Indie SaaS economics, not enterprise budgets.
Telegram-Native Surfaces: Python bots with multi-state ConversationHandler FSMs and fuzzy-match NLP; Telegram Mini Apps on Next.js 16 + React 19, initData-authenticated.
Browser-Based Automation: 100% client-side CSV/Excel tools — auto-column detection, real-time preview, files never leave the browser. Zero backend, zero compliance surface.
Pure-Function Domain Engines: Date and pricing logic isolated from I/O — no cron drift, no DB desync, edge cases handled mathematically.
Selected Case Highlights:
PriceShift — Cut bulk-pricing updates from 20 min to under 2 min for a 500+ SKU retailer. Non-technical operator, zero production errors since Feb 2026.
PingBoost — Stripe → Resend → license → embeddable widget loop on a $5 VPS. Replaces $19/mo SaaS widgets with a $39 lifetime license.
ByeSubs — Python bot + Next.js Mini App over one domain model. Mathematical date engine eliminates the edge cases that break spreadsheet tracking.
Next Steps for Engagement:
Send a direct message or invite me to your job post. We'll do a 20-minute architecture call to map your domain model, monetization, and the smallest end-to-end loop to your first paying users.
Skills and abilities
Portfolio
-
Multi-Channel Chat Widget SaaS — Next.js + Fastify + Stripe
Online Stores & E-commerce
I built PingBoost: a self-hosted SaaS that drops WhatsApp, Telegram, and Viber on any site through a single 15 KB gzipped snippet for $39 lifetime, replacing $19–29/mo widgets. Stack: Next.js 16 static landing, Fastify license server (SQLite WAL), TypeScript widget. Loop: Stripe Checkout → Resend key delivery → /build visual editor → domain-bound auto-binding license. Three shipped releases, zero breaking changes — every v1.0 snippet still works in v2.1. I build similar end-to-end SaaS loops tailored to your stack. Let's ship yours.
-
Bulk Price Updates in 2 Minutes — Browser Tool for E-commerce
Online Stores & E-commerce
Shop owners burn 10–20 minutes editing Excel for every bulk price change and usually need a developer. I built PriceShift — a browser-based pricing tool that parses XLSX/CSV catalogs, applies hierarchical category markup (subcategory > category > global), and exports in ~2 minutes. **100% client-side — pricing data never leaves the browser.
Client: B2B e-commerce business selling furniture to educational institutions (kindergartens, schools). Catalog: 500–5,000 products across multiple categories, exported as XLSX/CSV with 50–100 columns.
… Problem: In an unstable currency environment, supplier costs shift constantly. The legacy workflow (export → Excel → manual formulas → re-import) took 10–20 minutes per session and depended on developer availability.
What I built:
- Browser-based pricing engine — XLSX/XLS/CSV/TSV processed fully client-side
- Multi-language column auto-detection (EN/RU/UA) for Prom.ua, Rozetka, WooCommerce, OpenCart, Shopify exports
- Hierarchical markup logic — subcategory overrides category overrides global
- Real-time preview with color-coded old-vs-new prices before export
- Format-preserving export — all 50–100 original columns kept intact
Result:
- Bulk repricing session: 10–20 min → ~2 min (80–90% time reduction)
- ~1 month of production use with no crashes, no data-loss incidents, no security incidents reported
- Lighthouse: Performance 99/100, Best Practices 100/100, SEO 100/100, Accessibility 90/100**
- Eliminates developer bottleneck for routine pricing ops
Stack: Next.js 16, React 19, TypeScript, Tailwind CSS 4, SheetJS, PapaParse. Static deployment on Vercel Edge — no backend, no database.
"Will my pricing data leak?" No. 100% client-side: no upload, no analytics, no third-party scripts, no server logs.
If you run an SMB e-commerce store and need privacy-safe automation for repetitive operational work, I build similar browser-first tools tailored to your platform and data shape.