Anton K.

Full-Stack Developer | Node.js, NestJS, React Native, Integrations & Bots 🤝 Why Work With Me? With 5+ years of experience as a full-stack developer, I build scalable web and mobile applications from scratch and connect them to the services your business already runs on. My core stack is Node.js, NestJS, TypeScript, React, and React Native, with deep experience in MongoDB, gRPC microservices, and third-party integrations. I have shipped products used by millions of users and worked on integrations for enterprise-grade platforms, so I understand both fast-moving startup delivery and production-grade reliability. 🚀 What I Offer: ⚙️ Backend Development: Scalable backends and microservices with Node.js, NestJS, and Express.js. REST, gRPC, GraphQL, and WebSocket APIs, with a focus on performance, security, and clean architecture. 📱 Cross-Platform Mobile Development: iOS and Android apps with React Native (CLI and Expo), including push notifications, deep linking, in-app subscriptions, and analytics. 🔗 Integrations & Automation: Slack apps, Jira and Atlassian apps (Forge, Connect, webhooks, JQL, post-functions), OAuth flows (Steam, Discord, Epic Games, Google), payment and CRM integrations. 🤖 Telegram & Discord Bots: Reminder bots, learning assistants, and automation bots, from design to self-hosted deployment. 🧠 AI & Voice Assistants: LLM-powered features and real-time voice pipelines (speech-to-text, LLM, text-to-speech) using the Anthropic API, Deepgram, and Cartesia. 🎨 Frontend Development: Modern web apps with React, Next.js, and Tailwind CSS. 🗄️ Database & Performance: MongoDB and PostgreSQL schema design, indexing, caching with Redis, and query optimization. 🥇 Notable Achievements: 🎮 Gaming Matchmaking Platform: Built and maintained the backend of a matchmaking platform with over 1.6M users on NestJS, MongoDB, and gRPC microservices, alongside the React Native mobile app. Implemented Steam, Discord, and Epic Games OAuth, push notifications, moderation tooling, and anti-fraud systems. ⚡ Matching Performance Optimization: Reduced the core user-matching operation from about 4 seconds to under 1 second through caching, batch queries, and MongoDB indexing. 💬 Slack and Jira Integration: Delivered features for an enterprise Slack/Jira integration, including Forge app deployment, webhook health monitoring and remediation, post-function integration, and access and security settings. 📚 English Learning App: Built a Next.js web app with a gamified pixel-pet system and a companion Telegram bot, plus batch-generated learning content. 🎙️ Voice Assistant: Built a Jarvis-style always-listening voice assistant on macOS with a streaming pipeline (VAD, STT, LLM, TTS). 🔎 Job-Scouting Telegram Bot: Built a self-hosted bot running 24/7 on a Raspberry Pi that watches 20 job sources, filters noise, scores leads with an LLM provider fallback chain, and drafts replies (Node.js, TypeScript, SQLite, grammY). 📊 Data Migration at Scale: Wrote and ran migration scripts moving 1.6M contacts into a marketing automation platform without downtime. 📩 Let's Collaborate! If you need a reliable developer to build your product, integrate it with Slack, Jira, Telegram, or Discord, or add AI features to an existing app, let's talk about what you're trying to build. 💻 Programming Languages & Frameworks: JavaScript TypeScript Node.js / Express.js NestJS React / React Native (CLI/Expo) Next.js Redux / MobX 🗄️ Database & Backend: MongoDB / PostgreSQL Redis RabbitMQ Firebase GraphQL gRPC WebSocket Microservices architecture 🔗 Integrations & Bots: Slack API / Slack apps Atlassian Forge / Connect / Jira REST API / JQL Telegram Bot API Discord OAuth / Discord bots OAuth 2.0 (Steam, Discord, Epic Games, Google) Webhooks and event-driven integrations Mautic / CRM integrations 🧠 AI & Voice: Anthropic API / LLM integration Pipecat Deepgram (STT), Cartesia (TTS), Silero VAD Claude Code 📱 Mobile App Development: Cross-Platform Development (iOS & Android) Push Notifications (FCM) Deep Linking / Universal Links Adapty Amplitude Mobile App Architecture & Design 🧪 Testing: Jest React Testing Library (RTL) Cypress / Playwright 🎨 Frontend UI Frameworks & Styling: Tailwind CSS Material-UI (MUI) Shadcn/ui Styled Components Bootstrap 🛠️ DevOps & Tooling: Git & GitHub Vercel CI/CD Raspberry Pi self-hosting Docker 📋 Project Management: Agile methodologies Development Lifecycle Management Code reviews