Résumé / SOFTWARE ENGINEER
CAO FENG
樹(Itsuki)
Backend, data platforms & product development
Software engineer with about nine years of experience spanning financial data platforms and performance improvement, healthcare domain modelling and reusable systems, and building a startup product from scratch. My strength is turning complex business requirements into maintainable, extensible systems and carrying the work through design, development and operations.
- ~9 years in software development
- Based in Tokyo · available from October 2026
- JLPT N2 · studying at a language school
Updated
Experience
Senior Software Engineer (Full-stack)
Sep 2021 – Jan 2026
iSoftStone Information Technology (Group)
Contributed to a financial-regulation data platform for global business teams, from requirements analysis and technical design to data-processing and calculation frameworks, production delivery and operational support. Worked in English with quants, business analysts, project managers and overseas users to turn regulatory and business requirements into maintainable systems.
- Built Java backend services for upstream data intake, ETL scheduling and data import into Opensee. Learned Spark and Scala from scratch and built a configurable ETL framework adopted by six business teams, supporting over 2,000 daily processing jobs.
- Optimised Spark resource allocation and processing logic, reducing a workload of over 100 million records from about two hours to under 45 minutes.
- Worked with business analysts, quants and users to clarify requirements and validate prototypes, delivering a Python framework for Basel SA-CVA capital calculations. Verified results against ISDA sample data and enabled global business teams to retrieve data and run calculations themselves.
- Provided global production support and on-call coverage across time zones. Supported users in the US and other regions in English, coordinating with teams and vendors to resolve data delays, performance degradation and system incidents.
- Independently identified the causes of four or more defects and performance issues and drove vendor fixes. Resolved a service slowdown affecting all users with the team.
- Reduced manual work through Jenkins regression automation, enabling repeatable validation of calculation results after business changes. Contributed to production delivery through pre-release validation, operating procedures and data migration.
- Handled task breakdown, developer guidance and code review. Documented and regularly shared implementation, operational and troubleshooting knowledge as a team reference for development and handover.
Key technologiesJava · Python · Scala · Spark · ClickHouse · Jenkins
Mid-level Java Engineer
Jul 2017 – Sep 2021
Guangzhou Hexie Medical Technology
As a core developer, handled requirements analysis, technical and architectural design, task breakdown, implementation and production maintenance. Turned medical and operational expertise into reusable software capabilities for chronic-disease management, health questionnaires and genetic-test reports.
- Led domain modelling for the chronic-disease platform, separating shared management workflows from disease-specific rules. Extended diabetes management to hypertension and supported rollout to agents across China.
- Redesigned questionnaire evaluation and genetic-report systems, separating shared processing from frequently changing business rules. Enabled doctors to configure questionnaires in Excel, reducing delivery time from about two weeks to three days; enabled genetic-test specialists to configure, test and publish report rules themselves.
- Led the team to release an insurance sales-channel system in one week, integrating customer management, inventory and third-party shipping systems to support order processing, dispatch and reconciliation.
- Introduced Spring Boot, DDD, Spock and code review to the team, with unit tests for management plans and core business rules.
Key technologiesJava · Spring Boot · Spring Data JPA · DDD · MySQL · Redis · Spock
Engineer (sole developer)
Oct 2016 – May 2017
Early-stage startup
As the company's sole developer, built a construction-machinery repair platform from scratch around a WeChat official account, taking the initial product through development and release.
- Implemented the workflow from an owner's repair request through fault confirmation to technician dispatch.
- Owned requirements, system design, Java backend development, deployment and day-to-day operations.
Key technologiesJava · MySQL · Git
Independent projects
Personal projects that I take from idea to development and release, using AI-assisted development to address needs from everyday life.
ニャ識
An iOS app for people living in Japan and studying Japanese, combining receipt-based expense tracking with real-life vocabulary learning. On-device OCR via Vision, storage in SQLite, and the user's own choice of AI provider through an API key held in Keychain.
View project道のり
An offline-first iPhone railway-travel app with itinerary timelines, offline route maps, GPS arrival reminders, and local travel journals. Trilingual, no account, no ads, data stays on the device.
View project就職手帖
A web app that brings a Japanese job search into one place: notes per company, application documents, and interview practice. React + Vite on the front end, a Cloudflare Workers + D1 API, Google sign-in via Firebase, and MCP so AI agents can help with company research and document review.
View projectJLPT Master Deck
A web app that connects with AI agents such as Codex and Claude Code through MCP, organising vocabulary, grammar and questions from study conversations into a structured personal learning knowledge base. Preserves knowledge beyond individual chats and uses it to generate JLPT review cards and exercises, with multilingual support and study records.
View projectMCP App Server
A TypeScript library that turns an existing web app into an OAuth 2.1-protected MCP server. Plugs in existing auth (Firebase, Supabase, Auth0, …) through a single identity function and provides PKCE, dynamic client registration, refresh-token rotation and revocation, scoped tools and a consent UI. Runs on Node.js, Cloudflare Workers, Deno and Bun, published on npm.
View project樹の句帖
Independently designed and developed a personal haiku website to publish original poems inspired by everyday scenes and seasonal observations. Simple typography and generous spacing create a quiet reading experience for exploring and revisiting the poems.
View projectTechnical experience
Professional experience
- Backend
- Java, Spring Boot, Spring Data JPA, MyBatis, REST API, DDD
- Data & DB
- MySQL, Redis, ClickHouse, Spark, ETL, Pandas
- Cloud & Ops
- GCP Compute Engine, Jenkins Pipeline, Linux, Tomcat, JUnit, Spock
- Programming languages
- Java, Python, Scala, SQL
Independent development
- Apps
- Swift, SwiftUI, SQLite, Vision OCR, Keychain, LLM API
- Web
- Astro, TypeScript, JavaScript, Chrome Extension
Education & languages
Akamonkai Japanese Language School
Passed JLPT N2 in December 2024. Currently enrolled in the school's Shin-Chukyu 2 class, developing practical Japanese skills through conversation and group discussion.
Inner Mongolia University of Science & Technology
B.Eng., Mineral Processing Engineering
Chinese (native) · English (professional use) · Japanese (JLPT N2)
Get in touch
For a résumé or a work history tailored to a specific role, please reach out by email.
[email protected]