Rin Arakaki, Engineer

Research Engineer, aisaac

Jul 2025 — Current, Tokyo, Japan

Technologies —

Full-Stack Engineer, JAPAN AI

Oct 2024 — Jun 2025, Tokyo, Japan

LLM/generative AI research and development.

• Architected and led development of AI call centre platform, defining infrastructure architecture, database schema, UI, and AI agent design. Researched UDP-based stateful communication protocols and Kubernetes network model, integrated with third-party telephony provider. Presented demo to CEO.
• Implemented call centre operator and customer matching, using mathematical optimisation.

Technologies — ChatGPT, Gemini, Kubernetes, Google Kubernetes Engine, Cloud VPN, Cloud Interconnect, Cloud Batch, Cloud Run, Cloud Scheduler, Cloud Tasks, Cloud Storage, SIP, WebRTC, PostgreSQL, C++, Python, TypeScript, React/Next.js, Express, gRPC

Full-Stack Engineer, Kakeai

Sep 2023 — Sep 2024, Tokyo, Japan

One-on-one platform with real-time AI transcription and summarisation features.

• Re-architected and rebuilt core calendar component, with external calendar syncing, recurrence rules, third-person event creation, and preferred time slot setting. Reduced complexity and codebase size by two-thirds and improved maintainability.
• Proposed fine-grained access control model for multi-tenant SaaS architecture to CTO.
• Analysed engagement data using causal inference (Python).
• Led mentor-mentee matching implementation using stable matching algorithm.

Technologies — Amazon Elastic Container Service, Terraform, Python, Ruby on Rails, TypeScript, Angular

Lead Back-End Engineer, Viagate

Apr 2023 — Aug 2023, Tokyo, Japan

Marketing research platform using eye tracking, and facial expression recognition.

• Designed, built scalable, cost-effective AWS data infrastructure from scratch; employed binary serialisation, event-driven architecture for time-series data ingestion, compaction, aggregation, querying.
• Designed database schemas, APIs, storage hierarchies; defined clear, consistent, broadly applicable interfaces across data infrastructure. Introduced Protocol Buffers (iOS, web front-end) ensuring schema consistency, minimising time-series data volume.
• Led backend team developing APIs fully leveraging PostgreSQL functionalities.
• Implemented video, image processing (Python, OpenCV) for data visualisation.

Technologies — AWS IAM, Amazon Cognito, AWS AppSync, Amazon EventBridge, Amazon Aurora PostgreSQL, Amazon S3, AWS Lambda, Python, Apache Arrow/Parquet, Protocol Buffers, GraphQL

Technical Lead, Delipicks

Jun 2019 — May 2020, Tokyo, Japan

B2B food delivery startup; joined 6 months after launch.

• Served as Technical Lead, defining technology strategy and aligning system development with business processes through Lean methodologies. Achieved estimated cost reductions equivalent to 12 customer support staff salaries annually.
• Identified future technical challenge/opportunity critical to viability and scalability of business model. Conducted technical research and proposed innovative solutions to CEO, using mathematical optimisation and genetic algorithms.
• Actively participated in full business development lifecycle: cold calling, establishing supplier relationships, deploying operations app to partner workplaces, and negotiating deliverables.
• Participated in UX workshops, implemented UI prototypes and conducted user interviews.
• Managed full recruitment cycle (sourcing, interviewing, hiring, onboarding) for two engineers, one mathematical optimisation specialist.
• Led a cross-functional team of five, including two software engineers, one QA, one designer and one project manager.
• Managed real-time coordination with customers, suppliers, delivery partners to resolve operational and system issues.

Technologies — Firebase, Python, JavaScript, React

Software Engineer, Styler

Aug 2018 — Mar 2019, Tokyo, Japan

Fashion retail platform connecting online interactions and in-store experience (OMO - Online-Merge-Offline / New Retail).

• Led technical decisions for infrastructure, database design, API development. Initiated and guided the architectural transition from a monolithic system to a modern SPA + API architecture, improving deployment frequency from bi-weekly to weekly.
• Built new engineering team from scratch as part of a team of 6 engineers. Participated in transition from offshore outsourced to in-house development.
• Developed categories and tags databases for e-commerce platform, enhancing both on-site search functionality (linked from owned media) and SEO performance.

Technologies — Google Kubernetes Engine, Cloud Functions, Cloud SQL, Ruby on Rails, Python

Software Engineer, MarketEnterprise

Apr 2016 — Dec 2017, Tokyo, Japan

Resale and rental business with complex operations.

• Architected and led development of organization-wide authorisation API, initiating legacy system modernisation into microservices architecture; synthesised CTO's project vision, conducted research, made key design decisions. Reduced API response latency from 7s in experiment to 0.2s in production.
• Implemented social sign-in functionality for e-commerce website, managing development from front-end and server-side logic through to database migration.
• Led data aggregation and transformation efforts deriving user behaviour insights. Collaborated closely with a public relations and a fulfilment manager.

Technologies — Amazon EC2, Amazon RDS MySQL, Amazon DynamoDB, Amazon API Gateway, AWS Lambda, Python, JavaScript

The Open University of Japan, Bachelor's Degree, Liberal Arts

Apr 2012 — Mar 2016, Tokyo, Japan

• Completed degree requirements in 2 years.

Founder, Synthetic

Dec 2020 — Present, Tokyo, Japan

AI-powered formal mathematical proof platform.

• Researching, developing database and graph/network-based search system for mathematical formulae.
• Investigating theorem provers and proof search engines.
• Researching formal proof generation based on LLM and reinforcement learning.

Technologies — Rust, Python, TypeScript, React/Next.js, Express