In a backend developer subteam of 6 and at an about 100 employees size Nylas APIs company, built new version of the backend system for sync information (including email, calendar, contract…..) from different provider(like Google, Microsoft, Icloud …. ) in Golang and maintain the old version in Python (used by over 200K developer, 12B api request per day, and 100TB processed daily data)

In a full stack developer subteam of 5 and at an about 2000 employees middle size e-commerce company, built the Developer Center(App Store) for 3rd party developers (used by above 100 companies, including TikTok) to set the configuration for their application in the Shopline E-commerce platform (used by over 350K merchants and 530M customers)-Enhanced the App Store page's front-end functionality by developing new features using React.js, Redux Saga, Axios, React Hook Form, StoryBook, and Webpack bundle analyzer in TypeScript. -Optimized front-end code, reducing the bundle size from 3.7MB (7.02s download speed) to 680 KB (1.89s download speed) through efficient tree shaking techniques-Developed new back-end features for the App Store page using Shopline's open-source sl-express framework, MongoDB, gRPC, Passport.js, ElasticSearch, and Jasmine, while adopting a microservices architecture in JavaScript.-Revamped the App Store page's back-end code, adopting a more single-responsibility and dependency injection approach for improved flexibility and maintainability.-Developed a high-throughput webhook sending program (handling about 3K messages per minute) using Shopline's open-source captin framework, AWS SQS, and Redis, implemented in Golang.-Contributed to IT infrastructure tasks, creating Dockerfiles, Kubernetes Helm charts, and GitHub pipeline CI/CD YAML files.-Assumed the role of DeploymentPIC, ensuring the safe deployment of JIRA cards to the production environment.-Undertook IT infrastructure responsibilities, including crafting Dockerfiles, Kubernetes Helm charts, and Bitbucket pipeline CI/CD YAML files.-Monitored the production environment using NewRelic and Grafana, addressed production issues through AWS CloudWatch, and resolved problems stemming from these issues.

In a back-end engineering subteam of 2 and at an about 15 employees cryptocurrency start-up company, built the server-side feature for 2 cryptocurrency wallet) mobile apps "DCBox" (used by above 3K users) and “Eurus”, and an admin-used website in Golang-Developed new back-end features for "DCBox" using the serverless framework, AWS service (including Lambda, SES , EC2 , DynamoDB, S3, Kafka) and protocol buffer, in Golang, employing a monolith architecture-Directly addressed inquiries from client developers.-Created server-side features for "Eurus" from the ground up, utilizing go-chi, Logrus library, PostgreSQL, GORM, ElasticSearch, Kibana, go-web3 in Golang, and implementing a microservices architecture.-Wrote smart contracts using Truffle.js, chainlink, OpenZeppelin in Solidity.-Monitored the production environment in NewRelic, Grafana, and Alchemy, diagnosing and resolving production issues traced through AWS CloudWatch.

In a QA subteam of 10 and at an about 200 employees middle size IT company, tested the web apps “Daocloud Enterprise” (used by big companies including Bank of Communication, Bank of China, SAIC Motor), which is the GUI of Docker and Kubernetes -Wrote the user guide for "Daocloud Enterprise" and utilized it as a comprehensive checklist during testing.-Developed test cases for both unit tests and system integration tests, conducting manual testing of the product.-Executed vulnerability testing, assessing the product for potential risks such as SQL injection, Cross-Site Scripting (XSS), Cross-site request forgery, and DOS attacks.-Created software testing programs for performance tests using Apache JMeter