Rin Arakaki, Software Engineer

Full-Stack Engineer, JAPAN AI

Oct 2024 — Current, Tokyo, Japan

Full-Stack Engineer, Kakeai

Sep 2023 — Sep 2024, Tokyo, Japan

One-on-one plaftorm.

• Rebuilt core calendar component, achieving 1/3 reduction from 20K+ lines of code. Supported various user interactions using pointer events. Replaced moment.js with Temporal, a new JavaScript standard datetime API.
• Conducted engagement data analysis using causal inference with Python.
• Proposed fine-grained access control for multi-tenant SaaS architecture.
• Took charge of implementing new matching feature using GA algorithm.
• Being a good mentor and collaborator to designer, product manager and QA.

Utilised — Python, FastAPI, Ruby on Rails, TypeScript, Angular

Lead Back-End Engineer, Viagate

Apr 2023 — Aug 2023, Tokyo, Japan

Market research and data analytics platform.

• Built scalable data infrastructure from scratch, including network, authn/authz, DB, storage, API and data pipeline.
• Designed a cost-effective architecture to handle time-series data spikes using Apache Parquet, Polars and EventBridge.
• Designed whole database schemas, APIs and storage hierarchies. Defined understandable, consistent and highly applicable interfaces across the entire data infrastructure. Introduced Protocol Buffers on iOS and web front-end to ensure schema consistency and reduce the volume of time-series data through binary formatting.
• Led backend team in developing APIs that fully leverage PostgreSQL's functionalities.
• Implemented video and image processing using Python and OpenCV for data visualisation.
• Created local environment for SQL query development and unit testing with JupyterLab. Improved development speed by making these environments available to team.

Utilised — AWS IAM, Amazon Cognito, AWS AppSync, Amazon EventBridge, Amazon Aurora PostgreSQL, Amazon S3, AWS Lambda, Python, Polars, Apache Arrow, Apache Parquet, OpenCV, Protocol Buffers, GraphQL

Founder, Synthetic

Dec 2020 — Present, Tokyo, Japan

• Researching database and text search system for mathematical formulae.
• Developing regular expression/proof search engine.
• Designed and developed build system and file format suitable for mathematical content management.

Utilised — Rust, TypeScript, React/Next.js, MathML

Technical Lead, Delipicks

Jun 2019 — May 2020, Tokyo, Japan

A food delivery startup. Joined 6 months after launch.

• Analysed and defined business requirements. Simultaneously developed business processes and information systems using the Lean framework. Estimated reduced costs amount to 12 customer support staff per year.
• Identified future technical challenge/opportunity that directly defines viability and scalability of business model itself. Conducted technical research and proposed innovative solutions to CEO.
• Took part in business development lifecycle, from cold calling, to establishing relationships with food suppliers, to rolling out our operations app to their workplaces and staff, to negotiating deliverables.
• Participated in UX workshops, implemented UI prototypes and conducted user interviews.
• Recruited 2 engineers and 1 mathematical optimisation specialist by searching, interviewing, making hiring decisions and onboarding.
• Led a team of 5 including 2 software engineers, 1 QA, 1 designer and 1 project manager.
• Managed real-time coordination with customers, suppliers and delivery partners to resolve operational and system issues.
• Took charge of food curation, writing, food styling and photography direction.

Utilised — Firebase, Python, JavaScript, React

Software Engineer, Styler

Aug 2018 — Mar 2019, Tokyo, Japan

A fashion retail platform, connecting online interactions and real-store experience (a.k.a. New Retail, OMO).

• Built a new team from scratch as part of a team of 6 engineers. Experienced transition from offshore outsourced development to in-house development. Improved deployment frequency from once every 2 weeks to once a week.
• Led technical decisions on infrastructure, database design and API development.
• Took initiative in architectural change from a monolithic to SPA + API.
• Developed categories and tags databases used in the EC platform.

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

Software Engineer, MarketEnterprise

Apr 2016 — Dec 2017, Tokyo, Japan

A resale and rental business with complex business operations.

• Led project for developing authorisation API for entire organisation. Synthesised CTO's project vision, conducted research and made decision on design. Reduced response latency from 7s in experiment to 0.2s.
• Took charge of data aggregation and transformation to get insights into user behaviour. Worked closely with a public relations and a fulfilment manager.
• Implemented web crawlers to build pricing system to be used for data visualisation and sales optimisation.
• Implemented social sign-in for e-commerce website, ranging from web front-end and server-side to database migration.

Utilised — 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 the Psychology and Education course.
• Earned credits required to graduate in 2 years.

Projects

KFL

Rust decoder/encoder and derive macros for KDL data format.