• Designed and implemented various RESTful API microservices to fulfil user requirements.• Migrated services to Azure Native Infrastructure by using ARM template, VMSS, Load Balancer and Powershell scripts.• Developed scenario-based instrumentation for RESTful API services and asynchronous queue-based checkpoint processing services to enable fine-grained monitoring and reduced incident response times.• Created monitoring dashboards to visualize the reliability, latency, request rate, error rate of the incoming requests and outgoing requests.• Refactored the build and deployment pipeline of a legacy repository by changing to VS2017 build to speed up the development and deployment.

• Reduced backend RESTful APIs response time by 90% by migrating from Lambda to Elastic Beanstalk to eliminate cold-start time. • Devised and implemented an algorithm for creating travel itineraries based on destinations and user preferences by calling Google and including various parameters in the calculation.• Created ETL (Extract, Transform, Load) process to load data stream into Redshift for data analysis.• Designed and implemented RESTful API services to support efficient and low-latency data retrievals.• Built a batch job service to sending push notifications to registered mobile devices via SNS.

• Reduced the runtime of the letter generation job by 30% by sorting and caching data. • Optimized old batch-programs runtimes by eliminating useless program logic and generating output files with minimum size.• Developed a batch program to efficiently send the interface files to the letter generation servers concurrently.

• Designed, analyzed, and implemented new features for insurance policy administration systems.• Implemented high-performance night batch programs to process transaction records using multithreading and load balancing.• Optimized pieces of code by caching data to minimize database access and remove useless checking logic.• Led a 6-member development team to fix 30 production defects in 3 months and performed code reviews to ensure high-quality work. • Debugged and applied emergency fixes, when necessary, to batch jobs during overnight monitoring.• Proposed different solutions according to user requirements and estimated development effort for each solution. • Investigated and fixed bugs under pressure for production, system integration test and user acceptance test and communicated with users during user acceptance test.

• Implemented a Point-of-Sale system using RFID technology to identify items in clothing stores and reduced customers’ average checkout time by 30%.• Developed a desktop application using RFID reader API to automate the RFID tag performance evaluation process, reducing the evaluation time from 30 minutes to 10 minutes.