Jiajun Li Email and Phone Number

• Enhanced the user registration system by implementing JWT (JSON Web Tokens), creating secure endpoints for user registration and login, generating and verifying tokens upon successful authentication, to safeguard against unauthorized access and session hijacking, mitigating potential risk of data breaches. Added the feature of invitation link, enabling the admin to generate and share a link to new users for registration, thus promoting user growth. • Developed and implemented a user profile page featuring user information display, editable user details, and profile picture uploads. Enhanced React components and utilized Axios for promise-based asynchronous HTTP requests. Converted diverse data types into strings using Canvas API to align with database design, improving user experience and customization. • Architected and developed a Kanban page with features for creating and editing tickets, managing workflow columns, assigning tickets to users, and enforcing Work in Progress (WIP) limits. Utilized React.js for responsive TSX component development and Express.js for middleware implementation, further increased the efficiency of sales management by enabling Agile workflow. • Implemented robust CI/CD pipelines using Github CI/CD to automate testing and deployment of authentication features, ensuring code quality. Leveraged Prettier and ESLint to enforce code style standards and eliminate redundant imports.

• Leveraged Python, Django framework and Flutter to enhance application search functionality by implementing a custom ranking method prioritizing results based on username, popularity, and activity. Designed real-time, synchronous search display and ensured accuracy through comprehensive unit tests, enabling users to find information more effectively and thoroughly. • Utilized Flutter’s state management tool to implement dynamic page refreshing for the feed, ensuring automatic updates upon event changes and manual reloads via swipe-down. This feature improved search result pagination and enhanced user experience, reducing userreported issues related to outdated information by 30%. • Developed comprehensive unit and widget tests for the Flutter application using Dart, achieving 93% coverage of frontend widget interactions and backend API responses. Identified and resolved 3 critical vulnerabilities using SonarQube, ensuring the reliability and stability of each commit, and resulting in a robust and high-quality application delivery.

• Utilized Java and Spring Boot to develop microservices for our financial investment application. Features included crawling trading data for stocks, synchronizing our database every 30 seconds using the Ashare API, and calculating key investment performance metrics. This constructed the core architecture of our application, providing reliable, accurate, and real-time financial insights for more than 60,000 daily active users. • Optimized MYSQL database schema for 8 high-traffic APIs, resulting in a 50% reduction in query execution time from an average of 200ms to 100ms by implementing compound indexes and query caching. Leveraged MyBatis for persistence layer implementation and mapping SQL queries to Java objects, streamlining data flow and enhancing overall performance and scalability. • Established a robust CI/CD pipeline using GitLab CI/CD to automate build, test, and deployment processes. This involved writing and maintaining automated test scripts with Mockito and JUnit, configuring build triggers for automatic test execution upon code push, and detecting vulnerabilities and unregulated coding practices using SonarQube, significantly enhancing code quality. Reduced the Code Error Rate (CER) by more than 13%, improving the overall quality and maintainability of the codebase. • Wrote comprehensive onboarding documentation on Confluence, covering work procedures, technical tool setup, product architecture, and user flow of our investment app. This documentation significantly streamlined the onboarding process, helping 4 new interns integrate into the team in less than 5 days.