XiuQi Tan

Senior Backend Developer with 6+ years of Node.js and JavaScript experience (meeting the 6+ year bar) and deep crypto/financial sector background spanning exchange API integration, trading systems, DeFi, and regulated banking. Maintains binance-api-node — a production open-source Node.js/TypeScript library for one of the world's largest crypto exchanges, with low-latency REST and WebSocket trading integration, resilient reconnect, and rate-limit handling used by external developers. Builds blockchain integrations on Ethereum and Solana: wallet flows, transaction signing, onchain data ingestion, and smart contract interaction from Node.js backends.

Experienced with microservices architecture, MySQL/MongoDB/PostgreSQL/Redis data layers, message and job queue patterns, and real-time systems that stay responsive under scale. Security-first habits from four years on a complex tier-1 Swiss banking platform at Cognizant — audit-grade delivery, access control, disaster recovery, and production stability. Proven fast learner (GCP certification on the job, multi-chain ramp-ups).

Singapore-based, fully remote since 2021, available immediately.

Senior Backend Developer — Crypto and Trading Systems - Independent Consultant - Remote, Singapore

(2024-07)

• Maintain binance-api-node, a production open-source Node.js/TypeScript library for Binance exchange integration — low-latency REST and WebSocket trading APIs, resilient reconnect/resubscribe, rate-limit handling, and typed interfaces relied on by external developers
• Build blockchain integrations in Node.js backends: Ethereum and Solana wallet flows, transaction signing, smart contract interaction, and onchain data ingestion feeding trading dashboards and reconciliation systems
• Develop real-time market data pipelines — high-frequency WebSocket streams with decoupled consumers, Redis caching and job queues, and PostgreSQL/MongoDB persistence that stays responsive under sustained load
• Design microservices for payment and financial workflows with idempotency, retry logic, and security-first API boundaries
• Ship with agile cadence for startup clients: feature design → implementation → deployment → iteration, deployed on AWS/GCP with Docker and CI/CD
• Technologies: Node.js, TypeScript, JavaScript, WebSockets, Ethers.js, Web3.js, Solidity, Solana, Redis, MongoDB, MySQL, PostgreSQL, AWS, GCP, Docker, Jest

Backend Developer — Web3 and FinTech - Independent Consultant - Remote, Singapore

(2021-01 - 2024-06)

• Built Node.js backends and wallet-integrated dApps for crypto and DeFi startup clients — staking flows, token contracts, payment integrations, and admin systems
• Developed Solidity smart contracts on Ethereum with Hardhat test suites; integrated MetaMask and WalletConnect into production frontends
• Created crypto market data ingestion and portfolio tracking services consuming exchange and onchain APIs
• Delivered e-commerce and FinTech payment flows with secure API integrations and production error handling
• Technologies: Node.js, JavaScript, TypeScript, Solidity, Hardhat, Web3.js, MongoDB, MySQL, PostgreSQL, Redis, AWS

Backend Developer — Enterprise FinTech - Cognizant - Singapore

(2020-06 - 2024-06)

• Actively participated in development of a complex platform: Java/Spring Boot microservices and APIs for a tier-1 Swiss banking client serving thousands of users with strict uptime and audit requirements
• Applied the highest security principles and standards — IT security compliance, access control, secret handling, and annual Disaster Recovery exercises protecting business continuity
• Built CI/CD pipelines and automated testing for reliable releases in a regulated financial environment
• Worked in agile cross-functional teams with QA, security, and operations stakeholders
• Technologies: Java, Spring Boot, SQL, MySQL patterns, RESTful APIs, microservices, JUnit, GCP, CI/CD, Agile

Full Stack Web Development Bootcamp - JavaScript, Node.js, SQL - Le Wagon, Singapore (2019 - 2019)

Bachelor's Degree - Nanyang Technological University, Singapore (2013 - 2017)