# Sizhan Xu

> Software Engineer @ Klaviyo

Location: San Francisco, California, United States
Profile: https://flows.cv/sizhan

## Work Experience
### Software Engineer @ Klaviyo
Jan 2024 – Present | San Francisco Bay Area
Email Platforms

### Software Engineer Intern @ Klaviyo
Jan 2023 – Jan 2023 | Boston, Massachusetts, United States
• Took full ownership and end-to-end implementation of an automatic email signing key pair rotation system in Python, including design, implementation, testing, documentation, and deployment. Achieved a remarkable 97% acceleration in email signing key rotation while significantly reducing error occurrences.

• Migrated existing email signing key from AWS Secrets to HashiCorp Vault for better secret access throughput. Setup HashiCorp Vault infrastructure for accessing HashiCorp Vault cluster using Terraform.

• Enhanced essential features within the company-wide internal HashiCorp Vault library.

• Coordinated with several SRE teams to integrate/bump dependencies and improve development/production parity.

### Software Engineering Intern @ Electronic Arts (EA)
Jan 2022 – Jan 2022 | Austin, Texas (Hybrid)
• Led the development of a full stack mobile application for KPI monitoring, including design, implementation, testing, documentation, and release, providing accessible and quantifiable data to aid leadership decisions in Customer Experience department.

• Collaborated closely with app stakeholders and the UI/UX team to fulfill end users’ needs and improve user experience.

• Utilized Agile scrum methodology, releasing daily new app builds to the leadership for rapid product iteration.

• Tools used: React Native, Redux, Firebase Auth, Firestore, Firebase Messaging, Google Cloud Functions, TypeScript, Jest.

### Software Enginner Intern @ Entre
Jan 2021 – Jan 2021 | Pittsburgh, Pennsylvania (Remote)
• Migrated the existing serverless AWS Lambda backend into microservices with unit tests ensuring migration quality, allowing additional features added to the app.

• Created and detailed backend API documentation on AWS API Gateway for the frontend and mobile teams, reducing the time spent by 40% in checking API specifications in all teams.

### Software Engineer Intern @ prinsta
Jan 2021 – Jan 2021 | NYC, New York (Remote)
• Developed chat room and opensource marketplace for the desktop software that comes with the company’s circuit board printer using C++, Qt, CMake, Node.js to expand user experiences.

• Created internal tools to streamline the development and maintenance process using Python and Qt. GUI tools written with Qt boosted opensource marketplace project batch management and Python scripts for circuit board design file conversions.


## Education
### Master of Science - MS in Computer Science
The University of Texas at Austin

### Bachelor of Science - BS in Computer Science
The University of Texas at Austin

### High School Diploma in None
Jiangsu Provincial Zhenjiang No.1 Highschool


## Contact & Social
- LinkedIn: https://linkedin.com/in/sizhan-xu

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Source: https://flows.cv/sizhan
JSON Resume: https://flows.cv/sizhan/resume.json
Last updated: 2026-03-29