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I design, build and operate production systems: from React components to Linux servers, from zero to CI/CD. Every layer.

Provision Linux servers, harden SSH, configure nginx reverse proxies with SSL/TLS, fail2ban auto-jails, DNS. Docker Compose multi-service stacks with healthchecks. PostgreSQL at scale (50M+ rows, composite/partial indexes via CONCURRENTLY, PgBouncer, window functions, JSONB, full-text search). RabbitMQ, Redis and Celery: configured, debugged and production-hardened.

GitHub Actions (reusable workflows, composite actions, matrix builds), GitLab CI, AWS SAM + Lambda, Amplify, CodeBuild, Cloudflare Workers, GCP App Engine, Fly.io, DigitalOcean (Droplets, Spaces), Supabase, Hasura Cloud. PM2 ecosystem, S3 static hosting with OIDC, SSH-based rollouts. I own the pipeline from commit to production.

Primary: TypeScript (NestJS, Express, Next.js, Payload CMS) + PostgreSQL. Systems: Rust (Axum, SQLx, JWT, WebSocket, Telegram bots) for high-throughput auth and API microservices. Python: FastAPI (ML classification with sentence-transformers), Django (content platforms), Flask (REST APIs), Frappe/ERPNext. Go, Java, C# when the job requires it.

React & TypeScript: 7+ years. Custom component libraries, state management (Redux, Zustand, reactive), SSR strategies. Canvas 2D, Three.js, WebGL. Author of the No-Framework Principle and the @denshya reactive ecosystem. Custom TypeScript compiler plugins (ts-patch, ESLint, TSServer, Vite).

RabbitMQ memory leak: A worker processing webhooks wasn't closing connections in the catch block. Every API error created a new connection without closing the old one. After 10,000 errors the connections consumed all memory and the server OOM-killed every 2-3 hours. Fix: finally block guaranteeing closure, graceful shutdown, memory growth alerts. Post-mortem

Brute-force attack: CPU pinned at 100% from thousands of concurrent auth attempts. Logged in, expanded log retention to preserve evidence, applied fail2ban auto-jail after 5 failed attempts, then disabled password auth entirely and switched to SSH key-only with certificates. Post-mortem

Query performance: A 5-table join was taking 8 seconds. Analyzed EXPLAIN plan, identified a sequential scan on a massive table, added a composite index. Query dropped to 80ms. Story

Database design at scale: Designed schemas for a CRM and transaction platform where tables grew to 50 million rows. Used B-tree, composite, partial and covering indexes. Added columns with DEFAULT NULL to avoid table locks, created indexes with CONCURRENTLY. Configured PgBouncer connection pooling. Story

Supply chain incident: Detected malicious code injected into one of my published libraries by a colleague. Documented the discovery process and remediation. Story

mindmap
  root((Valery Zinchenko))
    Systems & Infrastructure
      Linux Servers
      NGINX Reverse Proxy
      SSL/TLS Certificates
      Docker Compose
      fail2ban
      DNS Management
      PgBouncer
    Backend
      TypeScript
        NestJS
        Express
        Next.js
        Payload CMS
      Rust
        Axum
        SQLx
        JWT Auth
        WebSocket
      Python
        FastAPI
        Django
        Flask
        Frappe
    Frontend
      React
      Three.js
      Canvas 2D
      Denshya Ecosystem
      Custom TS Plugins
    Cloud
      AWS
      GCP App Engine
      Cloudflare Workers
      Fly.io
      DigitalOcean
    CI/CD
      GitHub Actions
      GitLab CI
      AWS SAM
      PM2
    Databases
      PostgreSQL
      MongoDB
      Redis
      RabbitMQ
    Languages
      TypeScript
      Rust
      Python
      C Sharp
      Go
      Java
    Tools
      Docker
      Hasura
      Supabase
      Vite
      Bun

Making the Web a better place through simple, standardized, atomized tools. github.com/denshya · 18 packages + tools

• Extended Bio: the full journey from PHP at 11 to Rust microservices
• Full Resume: detailed work history, education, certifications
• Work Stories: server attacks, database crises and production incidents
• Early Projects: PHP, jQuery and CS:GO gambling sites from 2015. Been at this a while.