Iurii Uses: #Redis

Wrongulator — The Calculator That Is Confidently Incorrect

A joke calculator that returns a deterministically wrong answer with a straight-faced reason — built as a share machine.

vatnode — EU VAT Validation API

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

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

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 →

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

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.

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.

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.

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

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

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