David Xie Li

San José, Costa Rica

• Contribute to security-focused engineering initiatives, investigating and implementing protocol-level improvements for encrypted communications — including cryptographic key management enhancements and rollout validation planning.
• Lead the design and implementation of telemetry, analytics and reporting solutions for real-time communication and AI-powered calling scenarios, enabling engineering teams to measure reliability, latency and service health.
• Design and deliver Kusto-based telemetry pipelines and Power BI dashboards that turn complex client and service telemetry into engineering insight used for operational decision-making.
• Own end-to-end investigations into reliability, latency and telemetry discrepancies, identifying root causes across multiple telemetry sources and driving fixes that improve data accuracy and diagnostic quality.
• Drive operational excellence through data-driven monitoring, production investigations, deployment validation, alerting analysis and continuous improvement of engineering health metrics.

San José, Costa Rica

• Worked on the client calling stack supporting Microsoft Teams infrastructure and calling features, delivering enhancements that improved product usability and user experience.
• Designed and implemented multiple features including the ability to restart Town Hall events, XL meeting functionality, and message optimizations for 100,000-user meetings.
• Implemented application components using test-driven development while adhering to agile methodologies.
• Refactored, maintained and improved large cross-platform codebases in both C++ and TypeScript.
• Developed customer self-help and online support experiences for Microsoft 365 worldwide commercial and consumer users — delivering personalised insights and answers that reduced Incidents per Million Engaged Users (IMEU) while increasing self-help success rates and customer satisfaction.
• Collaborated with cross-functional teams to design and develop features that address customer needs and improve the overall support experience.

San José, Costa Rica

• Built products (internal tools and web applications) and services (backend processes and APIs) supporting the Asset Management tooling that tracks and audits Amazon's worldwide hardware asset ordering — laptops, monitors and peripherals.
• Leveraged AWS to build and deploy scalable, reliable serverless solutions operating at global scale, delivering low-latency, highly available services for a diverse range of stakeholders.
• Participated in code reviews and provided constructive feedback to raise overall codebase quality.
• Used agile development methodologies to ensure timely delivery of high-quality software.

San José, Costa Rica

• Communicated directly with customers to understand and promptly resolve Exchange Online (EXO) issues.
• Used log analysis and troubleshooting tools to break down complex problems and develop tailored solutions.
• Collaborated with senior engineers to analyse EXO source code and provide feedback for product enhancement.
• Participated in case triage meetings, contributing insights on challenging problems and promoting cross-functional cooperation.

San José, Costa Rica

• Increased cybersecurity capability across OAS Member States by developing CSIRTAmericas — a hemispheric network of National Computer Security Incident Response Teams that exchanges threat information, provides technical assistance, trains specialists and strengthens regional incident response.
• Designed instruments to evaluate the use of CSIRTAmericas services among Member State CSIRTs and ran a study to identify service improvements.
• Helped organise capacity-building initiatives including workshops, cybersecurity exercises and regional events.
• Performed functional testing in the MISP (Malware Information Sharing Platform) CSIRTAmericas laboratory and created supporting materials to streamline MISP adoption for Member State CSIRTs.