👋 Hi, I'm Sergei Shestak

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💼 Lead Developer / CTO | TypeScript • NestJS • Web3 • DeFi

I'm a technical leader and full-stack engineer passionate about building scalable Web3 products and bridging AI and blockchain.
With 12+ years of experience, I specialize in TypeScript, NestJS, and decentralized systems architecture.

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🚀 About Me

• 🏗️ Architect — Designing and building products from scratch
• 👨‍💻 Developer — Creating scalable backend & Web3 systems
• 🧠 Tech Lead — Mentoring teams and conducting code reviews
• ⛓️ Blockchain Enthusiast — Integrating Web3 into real-world products

🔭 Currently building Episteme — an AI-powered prediction market combining science, DeFi, and Web3.

💡 Exploring the intersection of AI, decentralized governance, and on-chain data.

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💻 Tech Stack

🖥️ Backend

Main: TypeScript, NestJS, Node.js
DB / Cache: PostgreSQL, Redis
Queues: RabbitMQ, BullMQ
APIs: REST, WebSocket

⛓️ Blockchain

Core: Solidity, Foundry, Ethers.js, Viem
Ecosystems: EVM, Substrate, Move (Sui/Aptos), Solana, TRON
Tokens: ERC-20, ERC-1155, ERC-4626
Domains: DeFi, Prediction Markets, MEV, Flashbots

🎨 Frontend

Next.js, React, Wagmi, RainbowKit, Vite, Vue.js

☁️ DevOps

Docker, Kubernetes, Helm, AWS, GitHub Actions, GitLab CI, Linux

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🏢 Experience

🎯 CTO / Technical Lead — Episteme

Jan 2023 — Present | AI-driven prediction markets, Web3, DeSci

• Leading technical team and full development cycle of decentralized science market platform (AI + Web3)
• Designed blockchain architecture based on Humanode (Substrate) and EVM
• Developed smart contracts (Solidity, Foundry) for betting, bonding curve, and tokens
• Built backend (NestJS, PostgreSQL, Redis, BullMQ, RabbitMQ) and contract indexer
• Created on-chain bots for automated betting and data updates
• Managed frontend (Next.js, React, RainbowKit) and implemented modular architecture
• 🚀 Improved platform reliability and scalability by 40% through CI/CD and service refactor

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🔧 Technical Lead / Senior Blockchain Developer — LPM ltd

Jan 2023 — Jan 2025 | NFT marketplace, DeFi, TRON / EVM projects

• Designed and implemented NFT marketplace architecture with custodial payments
• Developed backend (NestJS) with queues, caching, and API integrations
• Created and audited smart contracts (Solidity), conducted internal code reviews
• Integrated DeFi protocol based on ERC-4626 and TRON network
• 🧠 Mentored developers, streamlined workflows, and optimized performance

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💎 Senior Developer — NDA Company LLC

Aug 2021 — Dec 2022 | Ethereum & EVM networks (DeFi, MEV, Flashbots)

• Developed high-performance bots and trading services for Ethereum networks
• Integrated with DEX protocols and analytics platforms (Uniswap, Dune)
• Built APIs and monitoring tools for automated strategies

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🏛️ CTO / VP of IT — LLC "ATA"

Dec 2019 — Aug 2021

• Built IT infrastructure from scratch, led internal development team
• Designed internal APIs, microservices, and DevOps pipelines

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⚙️ CTO — LLC "Vladtime"

Nov 2018 — Dec 2019

• Designed microservice architecture and CI/CD pipelines
• Developed ERP systems and implemented monitoring solutions

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🔨 Fullstack Developer / SRE — LLC "Vladtime"

Jan 2015 — Nov 2018

• Developed websites and internal systems
• Administered Linux servers, optimized DBs and infrastructure

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🎓 Education

Far Eastern Federal University (FEFU)
Faculty of Radio Electronics and Computer Engineering
Specialty: Computing Machines, Complexes, Systems and Networks
Graduated 2009

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🛠️ Skills

🧩 Core Development

• Languages: TypeScript, JavaScript, Solidity, Move, Rust (basic), SQL
• Frameworks: NestJS, Node.js, Express, Fastify
• Patterns: OOP, Dependency Injection, Repository Pattern, Event-driven architecture, CQRS
• Testing: Jest, Foundry (Solidity), Hardhat, Chai, Supertest
• API Design: REST, GraphQL, WebSocket, OpenAPI/Swagger
• Performance: Caching (Redis), load balancing, DB optimization, queue-based processing

⚙️ Backend Engineering

• Databases: PostgreSQL, MongoDB, Redis
• ORM / Query Builders: TypeORM, Prisma, Mongoose
• Messaging / Queues: RabbitMQ, BullMQ, Redis
• Infrastructure: Docker, Docker Compose, Kubernetes, Helm
• Monitoring & Logging: Prometheus, Grafana, Loki, ELK Stack
• Authentication / Security: JWT, OAuth2, RBAC, SIWE, rate limiting, encryption

⛓️ Blockchain Engineering

• Smart Contracts: Solidity, Foundry, Hardhat, OpenZeppelin, ERC-20 / ERC-1155 / ERC-4626
• Web3 Development: Ethers.js, Viem, Web3.js, wagmi, RainbowKit
• EVM & Beyond: Ethereum, BSC, Polygon, TRON, Solana, Sui (Move), Substrate
• DeFi / DEX: Uniswap, 1inch, 0x, MEV, Flashbots, liquidity pools, bonding curves
• Automation: On-chain bots, keepers, transaction batching, calldata encoding

🧠 Architecture & Leadership

• System Design: Microservices, modular monoliths, event sourcing
• CI/CD: GitHub Actions, GitLab CI, Docker build pipelines
• Version Control: Git, Git Flow, code review best practices
• Team Management: Mentoring, onboarding, architecture documentation, task decomposition
• DevOps Mindset: Infrastructure as code, container orchestration, scaling strategies

🎨 Frontend

• Frameworks: Next.js, React, Vue.js
• Web3 Tools: Wagmi, RainbowKit, WalletConnect
• Bundlers / Tools: Vite, Webpack, pnpm, ESLint, Prettier

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💬 Open to opportunities: Full-time / Part-time / Project-based | Remote work | Relocation available

Made with ❤️ by Sergei Shestak