cooller458
Senior Blockchain Developer
| Backend Engineering Node.js, NestJS and Express services; REST, GraphQL and WebSocket APIs; JWT/OAuth/HMAC auth; PostgreSQL and MongoDB data modelling; serverless backends on Cloudflare Workers; Dockerized CI/CD. | Frontend & Web Applications React and Next.js applications with Redux/Context state, wallet-connected dApp UIs (Wagmi, Ethers.js), Chrome extensions, Electron desktop apps and Telegram Mini Apps.
| Fintech & Exchange Systems Centralized, decentralized and OTC exchanges; matching engine, double-entry ledger, market-data streaming, payment systems, wallet infrastructure and white-label exchange products. | Smart Contracts & Blockchain Solidity for launchpads, NFT marketplaces, lending, staking and subscriptions; audit remediation; EVM-compatible L1 design, L2/L3 (Arbitrum, Optimism, zkSync Era), BSC–TON bridges.
| Real-Time & Game Backends Microsoft PlayFab backends for Unreal Engine 5, in-game crypto payments and item markets, Telegram games on TON, commit-reveal game engines, in-game tokenomics. | Trading Automation & Analytics Multi-strategy CEX trading architecture (risk, OMS, execution), arbitrage bots, MQL5 and Pine Script, on-chain analytics and data tooling.
| Fintech & Exchange Systems Centralized, decentralized and OTC exchanges; matching engine, double-entry ledger, market-data streaming, payment systems, wallet infrastructure and white-label exchange products. | Smart Contracts & Blockchain Solidity for launchpads, NFT marketplaces, lending, staking and subscriptions; audit remediation; EVM-compatible L1 design, L2/L3 (Arbitrum, Optimism, zkSync Era), BSC–TON bridges.
| Real-Time & Game Backends Microsoft PlayFab backends for Unreal Engine 5, in-game crypto payments and item markets, Telegram games on TON, commit-reveal game engines, in-game tokenomics. | Trading Automation & Analytics Multi-strategy CEX trading architecture (risk, OMS, execution), arbitrage bots, MQL5 and Pine Script, on-chain analytics and data tooling.
Experience: 5 years
Yearly salary: $72,000
Hourly rate: $25
Nationality: 🇹🇷 Turkey
Residency: 🇹🇷 Turkey
Experience
Full Stack Dev
Venator Universe 2024 - 2025
• • Built the blockchain connectivity layer for the in-house game Venator Universe. Developed a payment system on the Whitechain network on top of Microsoft PlayFab, the backend powering the Unreal Engine 5 client. Built an in-game marketplace for buying and selling crafted items with cryptocurrencies via the PlayFab Catalog.
Full Stack Dev
Bit5 2023 - 2024
Bit5 · İstanbul 2023 2022 – 2023 2019 – 2020 Freelance Blockchain & TON Developer, Consultant MaxiRuby · Denizli (maxiruby.io) Layer-1 Fintech TON · Tools MigoChain Architect • Sovereign EVM-compatible Layer-1 (PoSA/Parlia) underpinning a product authenticity and supply-chain platform (MigoSeal, MigoNFT, MigoID) for Turkish e-commerce and geographical-indication goods; authored the architecture proposal and economic model; first partner brand live. Exchange & Trading Systems White-label exchange · CAEOS · trading bots • • • • Rebuilt the NFT marketplace contracts and set up zkSync Era infrastructure. Closed contract vulnerabilities, raising the Hacken security score from 0 to 9.2 (hacken.io/audits/bit5). Designed the NFT lending & borrowing system and bridge components. Built and successfully closed the NFT launch system, raising $250K
CTO
Balance Network 2022 - 2024
Balance Network · İstanbul • • • Built a full fintech product suite across contracts, backend services and web interfaces: centralized exchange, DEX (swap), NFT aggregator, IDO launchpad, NFT presale (PixyBox) and decentralized OTC system. Researched Ethereum Layer-3 and built tx-batch bridge software for Arbitrum and Optimism (balancescan.io). Built mobile/extension infrastructure for centralized and decentralized wallets, plus multi-wallet technology and its security systems.
Skills
backend
blockchain-engineer
front-end
mobile
smart-contract
web3
solidity
english
turkish