Iurii Uses: #TypeScript

n8n Community Node — EU VAT Validation in Workflows

Community node that puts VIES VAT validation and EU rate lookups inside n8n, so an onboarding or invoicing workflow can decide on a real VAT number instead of

pi-pi.ee — Live Custom-Colour Preview

Recolour a product photo to any colour in the browser, instantly — an SVG duotone filter tints transparent master images on the fly, so a shop can offer

pi-pi.ee — B2B Deal & Document Portal

Internal sales portal that turns a wholesale deal into a full set of trade paperwork — pro forma, contract, commercial invoice, packing list, CMR and more —

vatnode-mcp — Official MCP Server for EU VAT Validation

Open-source MCP server that lets Claude Desktop, Cursor and other MCP clients validate EU VAT numbers and look up rates directly in chat.

HTPBE? — Internal Admin Dashboard

Role-gated admin dashboard for the HTPBE? SaaS platform — real-time KPIs, per-user quota tracking, and a zero-dependency bar chart, all server-rendered via

HTPBE? — PDF Verification Workflow Animation

Looping SVG animation illustrating a PDF verification pipeline — document stack, cloud processing, and green/red folder sorting — built with pure CSS

pi-pi.ee — i18n B2B Presentation PDF Generator

On-demand PDF presentation generator for 31 European markets — one codebase, one URL pattern, streamed directly from a Next.js route handler with zero storage

eu-vat-rates-data — Free & Open-Source EU VAT Rates Dataset

Free, open-source EU VAT rates for all 27 member states + UK. Published as native packages for npm, PyPI, Packagist, Go, and RubyGems.

vatnode — EU VAT Validation API

Developer-first SaaS API for EU VAT validation via VIES with Redis caching, change monitoring, and webhook notifications.

pi-pi.ee — B2B E-commerce for Waterless Urinal Systems

i18n B2B e-commerce platform for waterless urinal products across 32 European countries with automated VAT handling, PDF invoicing, and CRM integration.

Pikkuna — i18n RAG AI System

RAG system on OpenAI and Upstash Vector with 30 language support. Includes streaming chatbot, hybrid search (semantic + keyword), AI ticket classifier, and

PostNord Shipping Automation

Automated PostNord label generation for 20–50 daily shipments, replacing 5–7 minutes of manual portal work per order.

Pikkuna — Real-time SVG Product Configurator

Client-side SVG configurator with live preview for designing vinyl curtains and roofing panels.

Pikkuna — E-commerce for Vinyl Curtains & PVC Products

International e-commerce platform with 30 locales, product configurators, AI chatbot, and fully automated order flow: Stripe → Zoho CRM → Airtable → Mailgun →

HTPBE? — Has This PDF Been Edited?

SaaS platform for PDF authenticity verification with a public REST API.

API key management for a public SaaS: hashing keys at rest, prefix + last-4 display, fail-closed validation, and revocation — plus the scoping, rotation, and

Prevent overselling under concurrent checkouts: reservations vs hard decrements, SELECT FOR UPDATE, deadlock-safe multi-line carts, and the payment window.

Gated B2B pricing in Next.js: per-account price lists, server-side access control so prices never leak to crawlers, and a deal-record data model where every

Subscription billing edge cases Stripe glosses over: proration, dunning, the state machine, cancellation timing, refunds, VAT, and webhook ordering.

Webhook security past the signature: replay attacks, payload trust, DoS, IP allow-listing, and secret rotation — what verification does not protect.

Feature flags without LaunchDarkly: a Postgres-backed, ~100-line system with deterministic percentage rollout, per-tenant overrides, and caching.

Semantic search for internal docs with Postgres and pgvector: chunk, embed, and query by meaning so people find the right document, not the exact words.

Idempotency key API design: make POST retries that don't double-charge — Postgres key table, ON CONFLICT claim, response replay, TTL, edge cases.

Stripe to Mollie migration in production: mandates instead of Subscriptions, thin webhooks, no proration, no portal, no Tax. What you rebuild yourself.

Build an internal CRM on Supabase: schema design, RLS policies, Next.js App Router frontend, realtime subscriptions, and an honest look at where the weekend

Multi-tenant SaaS database design: shared schema with RLS, schema-per-tenant, and database-per-tenant — trade-offs, real pitfalls, and when to use each.

Production healthcheck endpoints: liveness vs readiness probes, dependency checks with timeouts, 200 vs 503 logic, Docker and Kubernetes config, and security.

PostgreSQL production patterns: UUID v7, soft deletes, RLS for multi-tenant SaaS, partial and covering indexes, PgBouncer connection pooling, and migration

BullMQ vs pg-boss vs node-cron for Node.js background jobs. Trade-offs between Redis and Postgres queues, retries, deduplication, and production monitoring.

JWT vs sessions vs OAuth for SaaS: token invalidation, mobile clients, refresh token rotation, and a decision matrix to pick the right auth pattern.

AI document processing in production: full PDF pipeline — OCR fallbacks, structured output, validation, cost at scale. Beyond naive GPT calls.

Add AI to an existing product without a rebuild. Three integration patterns, how to pick the right one, and what production-ready AI actually demands.

Use linkinator to catch broken links before production: local URL rewriting, --silent flag, GitHub Actions integration, and false positive patterns for

Agency codebase handover checklist: first 48 hours, security triage, architecture mapping, and how to write a takeover assessment. Practical guide.

Data format comparison: JSON, YAML, TOML, CSV, Protobuf, MessagePack — tradeoffs, performance, and a decision framework for production systems in 2026.

How to build a React product configurator with Zustand state, DaisyUI components, Motion animations, and live SVG preview — architecture, pricing logic, and

Real-time Next.js admin dashboard: TanStack Query polling, Zustand for filter state, Sentry error boundaries per panel, and a zero-dependency bar chart.

IndexNow implementation guide for Next.js: key generation, TypeScript client with retry logic, GitHub Actions workflow, and pitfalls that break submissions

GDPR-compliant analytics with Umami: no cookies, no consent banner, self-hosted or cloud — and when server-side GA4 is still the right call for EU products.

PostNord API and Zoho Desk automation for EU e-commerce: the undocumented gotchas — 200 OK empty arrays, EU data center URLs, token caching — with production

Migrate middleware.ts to proxy.ts in Next.js 16 without breaking auth.

Production transactional emails with React Email and Resend: PDF invoice generation via react-pdf, Vercel Blob temporary storage, and BullMQ Stripe webhook

Self-host a Node.js API on a €6/month VPS: Caddy reverse proxy, Docker Compose, zero-downtime deploy script, and GitHub Actions CI — complete production setup.

How to publish one dataset to npm, PyPI, Go Module, RubyGems, and Packagist automatically with GitHub Actions — architecture, versioning, and per-ecosystem

Next.js view counter with Upstash Redis over HTTP: atomic INCR, Edge Runtime for zero cold starts, React Strict Mode fix, and slug namespace gotchas.

React masonry layout that keeps left-to-right card order with variable heights — where the popular CSS column-count trick silently breaks.

UUID v7 vs v4 in PostgreSQL: why random UUIDs fragment B-tree indexes, how UUID v7 fixes it, benchmarks at 5M rows, and Drizzle ORM migration steps.

CSS SVG animation with pure @keyframes: sync multiple tracks, fix the SVG transform override trap, and build smooth loops without GSAP or Framer Motion.

Next.js dynamic OG images with Satori: why opengraph-image.tsx hangs Turbopack at 400% CPU, how API routes fix it, plus WOFF2 and Twitter card gotchas.

E-commerce order automation that cut 160+ hours/month of manual work to zero: Stripe webhook to VAT invoice and tracking in under 2 minutes.

EU VAT validation in Next.js: VIES caching with Redis, three-state results, reverse charge logic, and audit logging — what actually works in production.

40+ point production SaaS checklist: auth, Stripe billing, PostgreSQL, rate limiting, email, monitoring, and security — with honest 8-week build estimates.

Stripe webhook production architecture: idempotency keys in PostgreSQL and Redis, BullMQ queue, signature verification in Next.js App Router — with full

Technical SEO built into Next.js: server-side rendering, dynamic meta tags, JSON-LD structured data, and automatic sitemap generation — no plugins, just code.

Detect tampered PDFs using xref table analysis, metadata mismatches, orphaned objects, and font changes — 7 forensic markers explained with TypeScript code.

Next.js i18n for 30 languages in production, not a 2-locale demo: next-intl routing, type-safe translations, hreflang at scale, and the formatting traps the

RAG chatbot for e-commerce: resolve 70% of support queries across 25 languages — ingestion pipeline, hybrid search, confidence thresholds, and streaming UI.

Redis rate limiting for APIs: sliding window ZADD with Lua atomicity, in-memory fallback, multi-tier limits by IP and API key, and developer-friendly response

Server-side GA4 and Meta CAPI in Next.js to recover the 30–50% of conversions adblockers and iOS hide from you.

Puppeteer vs @react-pdf/renderer for Node.js PDF generation, decided by production use, not benchmarks: which survives Vercel's serverless limits, which

Turborepo monorepo with Next.js and Hono, sharing one set of TypeScript types across frontend and backend.