Resume

≪Business Domains≫: Financial Health, Decentralize & Centralize Exchange Financial, Payroll & Financial Systems

≪Technical Domains≫: Fullstack

≪Self PR≫: Senior Backend Engineer with more than 7 years of experience building scalable financial and blockchain-related systems using Node.js and TypeScript. Specialized in performance optimization, microservice architecture, and high‑throughput backend services. Proven track record improving system performance (5–10x), reducing infrastructure costs (15 pods to 2 pods), and delivering complex features in production environments. Experienced working directly with product teams to translate business requirements into scalable technical solutions.

・Platform: NodeJs

・Programming language: Typescript, Javascript, PHP

・Framework : NestJs, ExpressJs, Moleculer, Vite, VueJs, ReactJs

・Database : PostgreSQL, MySQL, MongoDB, Redis

・Database Lib : TypeORM, Sequelize, Knex, Prisma, Mongoose

・Queue : SQS, BullMQ, Kafka, Gearman, RabbitMQ

・DevOps: Docker, Github & CICD, AWS(EC2, S3, SQS, SES,...), Lens, K8S, PM2

・Blockchain network: BSC, Polygon, Xinfin, Cardano, Aura, and Hedera

・Salary Hero - Senior software engineer - May 2024 - NOW

・FPT - Senior backend blockchain engineer - Sep 2023 -> May 2024.

・VMO - Senior backend blockchain engineer - Sep 2022 -> Sep 2023.

・Sotatek - Senior/Lead backend engineer - Apr 2021 -> Sep 2022.

・GHTK - Fullstack Developer - Sep 2019 -> Apr 2021.

≪Project≫: Salary Hero (Salary Hero company)

≪Business≫: Financial health platform providing payroll management, earned wage access, and employee financial services for enterprise clients, serving more than 200K active users.

≪Role≫: Senior Software Engineer (feature owner across backend, frontend, CI/CD and infrastructure; core member of the Guardians Team)

・Worked across 20+ microservices and the wider engineering ecosystem, covering backend, frontend, CI/CD, and infrastructure.

・Worked independently across Product, Mobile, Console, and DevOps teams to align requirements, drive technical decisions, resolve cross-team dependencies, and deliver scalable solutions.

・Designed and documented technical solutions, planned implementations, and broke down complex features into actionable tasks for the development team.

・Platform & Language: Node.js, TypeScript

・Backend: NestJS, ExpressJs, microservice architecture (20+ services), REST API

・Frontend: ReactJS

・Database: PostgreSQL, Redis

・Database Lib: TypeORM, Prisma, Sequelize, Knex

・Queue: AWS SQS, RabbitMQ

・Testing: Jest, Supertest

・DevOps & Cloud: Docker, Kubernetes (K8S), Lens, Grafana, GitHub Actions CI/CD, AWS (EC2, S3, SQS, SES)

・Others: AI-assisted development workflows (Claude Desktop & CLI, Github Copilot, OpenCode)

・Took ownership of a long-standing performance issue in the Voucher Service, identifying and resolving multiple root causes across database queries, ORM operations, and service architecture; reduced production infrastructure from 15 overloaded pods to 2 healthy pods, improved average API response time by 2×, and accelerated some APIs by up to 10× while increasing test coverage from 10% to 70%. Case study: https://matthewcodes.tech/blog/how-i-turned-15-struggling-pods-into-2-healthy-ones/

・Contributed to the adoption of AI-assisted development workflows, reducing development time and improving engineering productivity across the team.

・Consistently delivered new business requirements on time while contributing 5,000+ code commits and reviews across a large-scale production codebase over 2 years.

・Selected as a core member of the Guardians Team, contributing to technical direction, solution reviews, and engineering best practices across the team.

≪Product≫: https://www.salary-hero.com

≪Project≫: Horoscope-v2 (FPT Company)

≪Business≫: A high-throughput blockchain data indexing platform that crawls and indexes transactions across Cosmos-based and EVM-compatible networks, providing fast transaction history queries without directly querying blockchain nodes. Handles 2+ TB of transaction data and continues to grow.

≪Role≫: Fullstack Blockchain (owner of the transaction and trace indexing pipelines for Sei and EVM networks)

・Owned the transaction pipeline for Sei and EVM networks, responsible for crawling, processing, and indexing blockchain transactions at large scale.

・Owned the blockchain trace processing pipeline, extracting and indexing contract execution traces to support function-call analysis and transaction investigation.

・Optimized high-volume data ingestion and query paths across transaction, event, and block data, including database partitioning and indexing for tables containing 700M+ records

・Designed and automated partition management, including creation of new partitions and validation constraints to support continuously growing blockchain data.

・Refactored chain-specific logic into a unified multi-chain architecture, enabling the system to support multiple blockchain networks without maintaining separate code paths.

・Designed and developed the frontend integration guide for Aura Network, providing developers with practical documentation and examples for integrating with the network.

・Platform & Language: Node.js, TypeScript

・Backend: Moleculer (microservice framework), Hasura GraphQL, REST API

・Database: PostgreSQL, Redis

・Database Lib: Knex

・Queue: Moleculer service broker over Redis transporter, BullMQ

・Blockchain: Sei, Aura Network, Cosmos SDK chains, EVM-compatible networks; CosmJS, ethers.js, node integration

・Frontend: ReactJS

・DevOps: Docker, Kubernetes (K8S), GitHub Actions CI/CD

・Optimized and migrated 10+ high-volume blockchain tables containing 10B+ records in total, introducing partitioning and indexing strategies that significantly improved query performance at scale.

・Evolved the platform from chain-specific implementations into a unified multi-chain architecture supporting Sei, Aura, and EVM-compatible networks, eliminating duplicated chain-specific logic.

≪Product≫: https://aurascan.io

≪Project≫: ERP Ecosystem (Large-Scale Payroll & Financial Systems for GHTK Company)

≪Business≫: Internal enterprise platform supporting core GHTK operations, including employee management, customer orders, logistics, payroll, and other business workflows, serving 30K+ shippers, 2M+ shops, and processing hundreds of millions of transactions per month.

≪Role≫: Fullstack Developer (owner of the payroll calculation system and its management tools)

・Owned the payroll calculation system for 20K+ employees, designing automated workflows to calculate salaries across multiple employee groups and compensation models.

・Designed and implemented payroll management and reporting tools for directors, managers, accountants, and operational teams to validate and manage employee compensation.

・Designed and implemented the employee check-in service as part of the company's internal workforce management platform.

・Worked cross-functionally with Mobile, Big Data, Accounting, and Business Analysis teams to define solutions and resolve complex payroll and business requirements.

・Maintained and evolved payroll logic to support monthly changes in business formulas and compensation policies while ensuring accurate and timely salary calculation.

・Monitored and optimized large-scale data processing and database workloads, applying caching, query optimization, indexing, partitioning, and architectural refactoring where appropriate.

・Platform & Language: Node.js, PHP, JavaScript

・Backend: ExpressJS, PHP (legacy ERP modules), CakePHP

・Frontend: VueJs, Vue Bootstrap

・Database: MySQL, MongoDB, Redis

・Database Lib: Mongoose, CakePHP ORM

・Queue: Gearman, Kafka

・Performance: query optimization, indexing, partitioning, Redis caching, batch processing on 1B+ record datasets

・DevOps: Linux, PM2, Docker, Jenkins CI

・Owned payroll processing for more than 70% of the company's employees, consistently completing salary calculations and updates on time without payroll delays.

・Reduced payroll calculation time from 2 days to 15 minutes (~99.5% reduction) through automation, system refactoring, and performance optimization.

・Maintained reliable performance on datasets exceeding 1B records while processing more than 120M new records per month.

・Initiated and built the company's first automated payroll management system, replacing manual developer-driven salary calculations and significantly reducing operational workload and processing time.

・Recognized as a Master Developer and Employee of the Year by the company.

≪Product≫: Internal using only. https://id.giaohangtietkiem.vn

≪Project≫: FCX (Sotatek Company)

≪Business≫: Decentralize exchange financial running on BSC and Stellar network which target to handle 25k order/s with 50k+ concurrent users.

≪Role≫: Lead Backend Engineer (technical lead for trading infrastructure, smart contracts and the project foundation)

・Worked directly with customers, Product Managers, Business Analysts, and QA to clarify requirements, define technical solutions, and resolve implementation challenges.

・Researched decentralized exchange (DEX) architecture and trading mechanisms, defining system flows and technical solutions for on-chain trading and settlement.

・Established the project foundation, including base architecture, development environment, sprint planning, task breakdown, estimation, and technical documentation.

・Created and maintained technical tasks, implementation guidelines, and development documentation to align the team on architecture, coding approaches, and project standards.

・Mentored 5 members, provided technical guidance, reviewed implementation approaches and pull requests, and helped unblock complex engineering issues.

・Designed and implemented core trading infrastructure, including order management, transaction processing, order matching, P&L calculation, and real-time updates via WebSocket and Redis.

・Designed and implemented smart contracts based on the 0x Protocol and OpenZeppelin, integrating on-chain trading logic with backend services.

・Built transaction processing and blockchain integration services for interacting with smart contracts and tracking on-chain transaction states.

・Developed automated unit and performance testing, using Jest and k6 to validate system correctness and performance under load.

・Deployed, monitored, debugged, and optimized production systems, improving reliability, performance, and security.

・Platform & Language: Node.js, TypeScript, Solidity

・Backend: NestJS, microservice architecture (order matching, transaction processing, real-time gateway)

・Smart Contract: 0x Protocol, OpenZeppelin, Hardhat, ethers.js, web3.js

・Blockchain: BNB Smart Chain (BSC), Stellar

・Database: Postgres, Redis

・Database Lib: TypeORM

・Queue & Realtime: BullMQ, Redis Pub/Sub, WebSocket (Socket.IO)

・Testing: Jest (unit), k6 (load & performance)

・DevOps: Docker, Lens, AWS (K8S, S3, SES), GitHub CI/CD

・Designed a high-throughput trading architecture targeting 10K–25K order per second and 50K+ concurrent users, with dedicated order matching, transaction processing, and real-time communication services.

・Recognized as the Company's Project of the Year for delivering the organization's first decentralized exchange (DEX) platform.

≪Product≫: https://www.velo.org

≪Project≫: Dex Screener (Sotatek Company)

≪Business≫: A multi-chain blockchain data indexing platform that continuously crawls and processes transaction events from Ethereum, BNB Smart Chain, Polygon, XinFin, and other networks to derive token prices and historical market data.

≪Role≫: Lead Backend Engineer (architecture owner for the multi-chain ingestion platform and lead on performance optimization)

・Worked closely with BA, PM, and the customer's technical team to clarify business logic, resolve technical challenges, and align implementation.

・Established the project foundation, including system architecture, codebase structure, development environment, engineering standards, and development guidelines.

・Created and maintained technical tasks, implementation plans, and documentation to break down complex blockchain indexing requirements into actionable work for the team.

・Mentored 5 members through technical guidance, code reviews, architecture discussions, and troubleshooting of complex implementation issues.

・Designed the multi-chain system architecture and established the project foundation, including codebase structure and development environment for the team.

・Designed and implemented high-throughput blockchain ingestion pipelines for crawling and processing transaction events across multiple networks.

・Built asynchronous processing infrastructure using Redis and BullMQ for reliable event processing and workload distribution.

・Built real-time data delivery using WebSocket and Redis.

・Led performance optimization and production troubleshooting, identifying slow queries and processing bottlenecks and improving performance through indexing, partitioning, query optimization, and logic refactoring.

・Developed load-testing scenarios using k6, reviewed pull requests, and provided technical support throughout feature development and production deployment.

・Platform & Language: Node.js, TypeScript

・Backend: NestJS, high-throughput ingestion pipelines, REST API

・Blockchain: Ethereum, BNB Smart Chain, Polygon, XinFin; ethers.js, web3.js, JSON-RPC & WebSocket event subscriptions

・Database: PostgreSQL (indexing, partitioning, query optimization), Redis

・Database Lib: TypeORM

・Queue & Realtime: BullMQ, Redis, WebSocket (Socket.IO)

・Testing: Jest (unit), k6 (load & performance)

・DevOps: Docker, Nginx, PM2, VPS deployment

・Achieved 10,000+ requests/second on a single 16-vCPU node with a 99.99% success rate while keeping server CPU utilization below 40%, validated through k6 load testing.

・Delivered the project ahead of schedule, meeting the customer's performance and reliability requirements, and supported deployment and production setup on the customer's VPS infrastructure.

≪Product≫: Product release was ultimately cancelled by the customer due to the downturn in the blockchain market.

≪Project≫: VIN NFT (Sotatek Company)

≪Business≫: An NFT platform built on the Polygon blockchain for managing, minting, transferring, and claiming digital assets, including automated synchronization and recovery of NFT metadata stored on IPFS.

≪Role≫: Fullstack Developer (Solo project, from architecture through blockchain integration and delivery)

・Worked directly with VIN's solution architecture team to clarify requirements, define system flows, and align technical decisions.

・Designed and implemented the backend architecture and project foundation from scratch, including development environment and Polygon blockchain integration.

・Built blockchain data ingestion and synchronization workflows to crawl and process NFT data and transfer history from the Polygon network.

・Implemented core NFT operations, including minting, claiming, transfers, NFT details, and collection/listing APIs.

・Built automated jobs for NFT synchronization and metadata recovery, handling unexpected IPFS expiration scenarios to preserve NFT data availability.

・Implemented the frontend for the NFT management platform, including authentication and user-facing workflows for interacting with NFT data and operations.

・Owned end-to-end delivery across backend, frontend, blockchain integration, and production deployment.

・Platform & Language: Node.js, TypeScript, Solidity

・Backend: NestJS, REST API, scheduled synchronization jobs

・Frontend: ReactJS, TypeScript

・Blockchain: Polygon, ERC-721, ethers.js, web3.js, IPFS (metadata storage & recovery)

・Database: MongoDB, Redis

・Database Lib: Mongoose

・Queue & Jobs: BullMQ, node-cron

・DevOps: Docker, AWS, GitHub CI/CD

・Designed and implemented the entire backend from scratch, covering blockchain integration, NFT lifecycle management, APIs, and automated data synchronization.

・Designed a recovery mechanism for unexpected IPFS metadata expiration, preventing NFT data loss and maintaining data availability.

・Delivered the project ahead of schedule with positive feedback from VIN's technical team and stakeholders.

≪Product≫: https://vinfirst.vinfastauto.eu/en

≪Project≫: Thanh Dat Computer (Private company)

≪Business≫: Shoping website of computer, camera and printer.

≪Role≫: Fullstack Developer (sole developer, from UI design through deployment and maintenance)

・Design UI, clear requirements.

・Took full responsible to build the website using nodejs and wordpress.

・Deploy and maintance product using hostinger.

・Migrate product to wordpress for good SEO.

・Platform & Language: Node.js, JavaScript

・Backend: ExpressJS

・Frontend: HTML, CSS, JavaScript, jQuery, Bootstrap

・Database: MySQL

・Hosting & Ops: Hostinger (domain, cPanel, shared hosting)

・The first project running on production.

・Experience about domain, setup, deploy and maintance website through hostinger.

≪Product≫: http://thanhdatcomputer.vn