Backend-focused software engineer with 6+ years building and operating production services in TypeScript, Python, and Clojure on PostgreSQL and AWS. Owns features end to end: API design through implementation and operation, data modeling, the React frontend, CI/CD, and on-call. Writes Rust and Emacs Lisp in open source and runs an AI-native workflow with coding agents.
Open Source
- leaf.el (★ 556): Declarative init.el configuration for Emacs.
- chrome-devtools: Rust CLI that shares Chrome DevTools Protocol (CDP) sessions across coding agents.
- feather.el (★ 94): Parallel Emacs package manager with async installs.
- seml-mode.el (★ 79): Major mode for SEML, HTML authoring in S-expressions.
- keg.el (★ 33): Elisp package development tooling with built-in testing and CI.
- Maintainer
- cask (★ 1.3k): project management for Emacs
- ivy-posframe (★ 422): ivy completion in a child frame
- skkeleton (★ 335): SKK input method for Vim/Neovim
Experience
Software Engineer · Toyokumo, Inc.
Jun 2024 – Present (on leave)
- Full-stack development of "kMailer," a kintone-integrated SaaS email delivery service: Clojure GraphQL API on PostgreSQL, ClojureScript and Next.js/React (TypeScript) frontend, deployed on AWS ECS.
- Designed and shipped 10+ roadmap features (HTML block editor, scenario-based email automation, delivery analytics, A/B testing), writing design docs to align product, design, and customer success.
- Raised the team's Release per Business Day from 0.8 to 2.1 by standardizing deployment, 1st among 6 teams. Merged 334 pull requests in 6 months (55/month), the most on the team.
- Led adoption of AI coding agents (Devin, Claude Code); zero-downtime migration from AWS Elastic Beanstalk to ECS (Docker), JVM 11 to 21 upgrade, and a 30% cut in GraphQL Codegen output.
Software Engineer, Backend Team Lead · Optarc LLC
Apr 2021 – May 2024
- Owned an automated ordering system on AWS from requirements to operations: order quantities computed from about 10M sales records covering the previous 30 days across 100 stores.
- Serverless microservices in Python on AWS Lambda with GraphQL APIs: Amazon Redshift for nightly batches, Aurora PostgreSQL for daytime OLTP, and Cedar policy-based authorization across 20+ endpoints.
- Led a backend team of up to 4 engineers with test-driven development (TDD), code review, and CI/CD; SQL tuning and metrics monitoring kept the system at 99.9% uptime.
Contract Frontend Engineer · Forcode Inc.
Jan 2022 – Jun 2022
- Built the React (TypeScript) frontend of a major music company's internal platform for artist master data and CD/record sales.
Part-time Software Engineer · Optarc LLC
Sep 2020 – Mar 2021
- Set up CI/CD (CircleCI) with automated tests for a 3-person team and lifted test coverage past 60% by wrapping side-effect-heavy code in end-to-end tests before refactoring.
Software Engineering Intern · pixiv Inc.
Sep 2020 (2 weeks)
- Migrated the pixiv Encyclopedia PHP application (100,000+ monthly users) to PSR-7/15/17 standards, turning 15+ global-state modules into unit-testable functions.
Skills
- Languages: TypeScript / JavaScript, Python, Clojure, Rust, SQL
- Backend: Node.js, REST and GraphQL APIs, microservices, serverless, OAuth 2.0 / JWT, Cedar, Amazon Cognito
- Databases: PostgreSQL (Aurora), Redis, DynamoDB, Amazon Redshift, data modeling, query tuning
- Cloud and DevOps: AWS (Lambda, ECS, EKS, S3, RDS, SQS, EventBridge, CloudFront, IAM), AWS CDK, Docker, Kubernetes, GitHub Actions, Nix
- Frontend: React, Next.js, ClojureScript, TanStack Query, Apollo Client, Tailwind CSS
- AI Engineering: Model Context Protocol (MCP), AI coding agents (Claude Code, Codex, Devin)
Writing and Talks
- Published 3 Clojure books at Tech Book Fest.
- Organizing member of Shibuya.lisp.
- 2025年からを生きるためのEmacs入門 (Tokyo Emacs Study Meeting, Aug 2024)
- Clojureで始めるTree-sitter (Tokyo Emacs Study Meeting, Oct 2024)
- Blog posts (Japanese)
Education and Certifications
- Hiroshima University, B.Eng., Faculty of Engineering, Cluster 2 (Apr 2015 – Mar 2020)
- Hiroshima University, Graduate School of Advanced Science and Engineering (Apr 2020 – Mar 2021, withdrawn)
- AWS Certified Solutions Architect – Associate (Amazon Web Services, Jun 2026, valid to Jun 2029)
- Applied Information Technology Engineer (IPA, Dec 2018)
- Senior High School Teacher License (Japan, Mar 2020)