>cat ~/cv.md--print-ready
// curriculum_vitae
Peifeng Wangワン ペイフン
Full-Stack Engineer12+ yrs · CN → JP
>head--summary
// summaryprofessional profilepython · ai · full-stack
Full-stack engineer and team lead with 12+ years building products from zero to one — across SaaS, e-commerce, robotics, and supply chain. Led a 10-person engineering team at Geetest while shipping production features. Co-engineered autonomous forklift navigation with CMU researchers at BITO Robotics. Architected a warehouse design automation tool at Shucheng AI, collaborating with co-founders from Stanford and University of Michigan. For the past three years, based in Tokyo and working across Japanese startups building SaaS and e-commerce platforms.
Strong in Python, Go, TypeScript, and Elixir. Comfortable owning the full stack — architecture decisions, backend systems, frontend delivery, and DevOps — in small teams where all of it sits at the same table.
On the side, building sky-finance: a local-first RAG pipeline with sentiment-bucketed retrieval, multi-provider LLM routing, and LLM-as-judge evaluation — running at under $0.50/month.
>ls ~/experience|sort--reverse-chrono
// experiencework history6 entries
Aug 2025 – Present
Kichijōji, Tokyo, Japan
Shopify e-commerce· Full Ownership
Full-Stack Engineer
Shopify-focused e-commerce company. Joined as an early core developer on a new internal SaaS initiative: a timecard management platform developed from its early foundation and currently running in internal pilot. Worked across product requirements, system architecture, real-time workflows, and end-to-end feature delivery.
- ▸Took ownership of feature design and technical architecture for the timecard SaaS, translating operational requirements into production-ready full-stack implementations.
- ▸Built a real-time kiosk view with Phoenix LiveView and WebSockets, enabling instant punch-in/out status updates across locations without polling.
- ▸Developed a live 2D canvas map using sprite graphics and Anime.js to visualize employee state transitions as game-style character movement triggered by punch events.
- ▸Collaborated closely with the team lead on foundational system design while independently delivering core product functionality from concept to pilot.
ElixirPhoenix LiveViewNext.jsTypeScriptPythonPostgreSQLAnime.jsDockerGitHub Actions
Aug 2024 – Jul 2025
Shinjuku, Tokyo, Japan
Portfolio & commerce SaaS· Lead Engineer
Lead Full-Stack Engineer
Japanese startup building portfolio and commerce products for creators. Stepped into the Lead Engineer role to rebuild the engineering function and deliver the company's commerce platform end-to-end.
- ▸Took ownership of architecture, delivery priorities, and team operations as Lead Engineer, rebuilding the engineering team and processes from the ground up.
- ▸Architected and launched a full commerce platform (Rails / Next.js / TypeScript / Stripe) handling 1,000+ transactions with per-order values ranging ¥10K–¥200K, integrated end-to-end from the Foriio main site through to payment settlement.
- ▸Maintained and refactored Ruby on Rails APIs supporting 2–3 million daily requests, improving stability and resolving recurring performance bottlenecks.
- ▸Modernized CI/CD pipelines across 10+ projects and 40+ servers — introduced modular GitHub Actions architecture for new projects, replacing monolithic single-file configs on key pipelines to reduce maintenance overhead.
- ▸Led a team of 4 engineers — conducting interviews, onboarding, task allocation, and priority definition while personally handling the most complex technical deliverables.
RubyRailsNext.jsTypeScriptPostgreSQLAWSGitHub ActionsCircleCIHerokuStripe
Jan 2023 – Jul 2024
Gennmu Technology
Nihonbashi, Tokyo, Japan
Staffing & tech· Japanese enterprise clients
Software Engineer
Tokyo-based staffing and technology firm serving major Japanese enterprises. First role after relocating to Japan — contributed across client-facing Salesforce projects and internal web development.
- ▸Delivered Salesforce Marketing Cloud low-code implementations for major Japanese clients including AU and UNITED ARROWS, involving SQL, JavaScript, and data analysis workflows.
- ▸Rebuilt and launched the company homepage using Flask, replacing the existing site with a cleaner, maintainable codebase.
- ▸Developed a gaming equipment e-commerce platform using Django, delivering a complete codebase for internal handoff.
SalesforceSQLDjangoPythonFlaskJavaScript
Jul 2019 – Feb 2022
Shanghai, China
Warehouse automation· Stanford / Michigan founding team
Full-Stack Engineer / Technical Director
Supply chain digitization company incubated by SF Express, China's largest logistics enterprise. Joined as a core engineer and took on Technical Director responsibilities — owning technology selection, architecture, and end-to-end team recruitment alongside a founding team from Stanford and the University of Michigan.
- ▸Re-architected the company's primary Python-based platform from the ground up after joining — redesigning core systems and establishing new technical foundations across front-end and back-end.
- ▸Architected and shipped a warehouse design automation tool that generates CAD, 2D, and 3D layout models from parametric web inputs, eliminating manual design cycles for logistics PoC clients.
- ▸Contributed to a Starbucks demand forecasting project (4,000 stores across China) — responsible for data cleaning pipelines and auxiliary web UI for model input and output.
- ▸Developed a WeChat Mini Program e-commerce platform for multi-channel sales distribution using Django and Vue.js.
- ▸Led full-cycle recruitment and managed a team of 5 engineers, owning hiring decisions, onboarding, and technical direction.
PythonFlaskDjangoVue.jsJavaScriptD3.jsPostgreSQLAlibaba CloudAWS
Jul 2018 – May 2019
Shanghai, China
Autonomous forklifts· CMU founding team
Senior Full-Stack Engineer
Robotics company specializing in autonomous forklifts and AGV systems, with a core team primarily from Carnegie Mellon University. Rebuilt the front-end and back-end of two core systems from scratch — a central control platform and a per-AGV on-board system — integrating directly with ROS in a live warehouse environment.
- ▸Rebuilt the AGV central control system (Flask / Redis / Vue.js) from scratch — implemented a custom WebSocket bridge to ROS topics for real-time bidirectional communication between the web platform and autonomous forklift fleet.
- ▸Developed a road network design tool using D3.js that constructs warehouse maps from QR code scans, allowing operators to define nodes, roads, and AGV task routes entirely through a web interface.
- ▸Built a per-AGV on-board monitoring system with direct ROS integration, enabling real-time status tracking and task management for a fleet of 5–10 autonomous forklifts.
- ▸Led a development team of 3 engineers across both systems.
PythonFlaskTornadoVue.jsMySQLD3.jsROSRedisWebSocket
Jun 2014 – May 2018
Wuhan, China
Bot-detection / CAPTCHA· 13th employee → team lead
Full-Stack Engineer / Web Team Lead
Cybersecurity startup best known for CAPTCHA and bot-detection — joined as the 13th employee, grew to ~200 employees and nearly 100 engineers during tenure. First engineering role after a career switch from sales — entered the industry as a self-taught developer and progressed to Web Team Lead within one year.
- ▸Joined as the sole web developer and became Web Team Lead within one year as the company scaled — ultimately leading a team of 10 engineers across front-end and full-stack projects.
- ▸Architected and delivered the core B2B customer platform — a user management and API key portal that scaled from under 10K to 200K registered users, rebuilt multiple times (Django → Flask + Django + Vue.js) to keep pace with growth.
- ▸Developed 10+ production web systems across the full product lifecycle — including three full UI rebuilds of the company homepage, an internal business intelligence dashboard for commercial operations, and web tooling for the machine learning team.
- ▸Rebuilt the company's primary web infrastructure from Django monolith to a modular Flask + Vue.js architecture, establishing the technical foundation the web team operated on through the company's growth phase.
PythonDjangoFlaskTornadoVue.jsReactMySQLRedisMongoDB
>pkg list|group-by--installed
// tech_stacktools & technologies4 categories · production-ready
01 / Languages08
PythonTypeScriptJavaScriptGoElixirRubySQLRust · learning
02 / Frameworks09
DjangoFastAPIPhoenixNext.jsReactFlaskVue.jsRailsExpo
03 / AI & Data09
ClaudeOpenAIOllamaPostgreSQLRedispgvectorRAGMySQLMongoDB
04 / Infra & Ops10
DockerLinuxGitHub ActionsAWSNginxGrafanaPrometheusAnsibleTerraformKubernetes
>ls ~/projects|grep--significant
// projectsselected personal work2 entries · side · self-funded
LLM-powered financial intelligence · running <$0.50/mo
End-to-end financial intelligence platform in Python — market and news ingestion, LLM-assisted cleaning, embedding, RAG retrieval, and strategy analysis. Running at under $0.50/month in cloud API costs.
- ▸Built an end-to-end financial intelligence platform in Python — market/news ingestion, LLM-assisted cleaning, embedding, RAG retrieval, and strategy analysis, running at under $0.50/month in cloud API costs.
- ▸Implemented hybrid RAG retrieval with PostgreSQL + pgvector, combining BM25 full-text search and HNSW vector search via Reciprocal Rank Fusion, with sentiment-bucketed context to ensure minority signals reach the model.
- ▸Designed multi-provider LLM routing across Ollama, OpenAI, and Anthropic Claude — structured outputs, prompt caching (~90% cost reduction), and per-call token/cost tracking surfaced in the dashboard.
- ▸Built an LLM-as-a-judge evaluation pipeline comparing sentiment-bucketed vs. flat retrieval across faithfulness, coverage, and actionability dimensions.
PythonFastAPIpgvectorClaudeOpenAIOllamaRAG
wangpeifeng.com
Personal Platform & Multi-Theme Design System
Designed and developed a unified personal platform combining blog, CV, portfolio, and journal into a single Next.js application with a fully custom multi-theme design system focused on typography, visual identity, and cohesive user experience.
- ▸Built a dynamic theme architecture with four fully distinct visual systems, each featuring unique typography, spacing, color palettes, and UI behaviors.
- ▸Engineered a terminal-inspired interface system emphasizing monospace typography, minimal UI abstraction, and high signal-to-noise presentation.
- ▸Created a cohesive cross-section experience spanning blogging, résumé rendering, timelines, and long-form storytelling within a unified design language.
Next.jsTypeScriptReactTailwind CSSDockerGitHub Actions
>cat ~/credentials/*.md|render--compact
// credentialseducation · patents · languages3 panels
EDUCATION01
Wuchang University of Technology
Environmental Engineering
periodSep 2007 – Jul 2011
cityWuhan, China
noteself-taught into software
PATENTS01
WO2021184193A1Computer-Aided Warehouse Space PlanningPCT · 2021 · co-inventor · Shucheng AI
LANGUAGES03
Chinesenative
Englishbusiness
Japanesebasic
— END_OF_CV · root@wang's-mac:~/cv$