Hiro Watt – Portfolio

A showcase of my projects, skills and experiences.

About Me

I'm Hiro Watt, a software engineer with experience in backend development (Java / Python / Go / Kotlin, etc.) for over 5 years. I also have experience in data analysis and app development.

Career

Responsible for the development of EC services at a leading e-commerce company in Japan.
Responsible for the development of email services at a leading email service company in Japan.

Strengths

Performance Improvement: I'm good at identifying and optimizing unnecessary processing and inefficient algorithms.
Maintainability-focused design: My strength is engineering code for prolonged service life.
Logical thinking and absorption: I'm good at learning new technologies and solving complex problems.

By taking advantage of my experience, I'm always eager to take on new challenges and explore new areas.

Skills

Programming Languages

JavaPythonGoC++KotlinJavaScriptTypeScript

Frontend Development

ReactNext.jsVue.jsHTMLCSSBootstrap

Backend Development

SpringBootVert.xNode.jsExpress

Databases

OracleDBMongoDBPostgreSQLMySQL

Tools & Others

GitCI/CDDockerWebpackJenkinsLinuxKarate

Other:

Familiar with solving algorithmic challenges in a wide range of languages—including Java, Ruby, Python3, C, C++, JavaScript, Scala, Go, and Kotlin—reflecting adaptability and cross-language fluency in technical problem solving.

Projects

Leading Email Service Company (in Japan) Projects

Development of a New Spam Classification Service for Outgoing Emails

In conjunction with the renewal of the spam classification and email sending/receiving systems, I was involved in the development of a new spam classification service for outgoing emails.

JavaVert.xMigration

MTA (Mail Transfer Agent) Renewal Project

In conjunction with the renewal of the spam classification and email sending/receiving systems, I was involved in the renewal project of the MTA (Mail Transfer Agent).

JavaGoMigration

Leading E-commerce Company (in Japan) Projects

System Renewal Project of API Applications

I participated in a project to renew an existing API system that had issues with maintainability and scalability, using Domain-Driven Design (DDD).

DDDClean ArchitectureJavaSpring BootRenewal Project

Development Support for BFF Handling Product and Store Information of E-commerce Service

I provided development support for a BFF (Backend for Frontend) application that formats product and store information data of an e-commerce service and passes it to the frontend.

KotlinSpring Boot

Development of a Cache Creation Batch to Resolve Delays in API Applications

To address the issue of response delays in an API application, I developed a prototype batch application that creates caches.

JavaSpring BatchKubernetesDockerJenkinsGreenfield Development

Analysis and Improvement of Troubles in API System

I conducted investigations into the causes of troubles in the API system, determined and implemented solutions, and reproduced the troubles.

RedisJavaSpring BootLinux

Feature Addition to API System

I was responsible for adding features to the API system used by store operators in a company deploying e-commerce services.

JavaSpring Boot

API Test Tool Introduction and Automation

I investigated and introduced an API automated testing tool, integrating functional testing into the CI/CD pipeline.

JenkinsKarateCI/CDAutomation

Development of Monitoring Efficiency Service for Large-Scale Sale Events

I contributed to risk management for sale event leaders by enabling centralized visualization of the status of services managed by each team.

React.jsNode.jsDockerGreenfield Development

Personal Projects

Migration of Personal Blog

Migrated a personal blog operated on Blogger to a static site built with Next.js and MDX.

Next.jsReact.jsTypeScriptMDXVercelBlogGreenfield Development

MTx_EA_Framework

A framework designed to streamline the development of Expert Advisors (EAs) for MT4/MT5, allowing developers to focus on implementing trading logic.

MetaTraderMQL4MQL5ForexTrading

Time Counter

A countdown app inspired by the movie TIME.

FlutterDartMobile App

MemorySpring

A project whose concept is to create a single, vast digital stream of consciousness where the memories and thoughts of all people merge.

JavaScriptTypeScriptReact.jsExpressNode.jsMongoDBVercel

MP-manager

MP-manager is a tool that automatically collects and organizes information on mitochondrial proteins recorded in MitoProteome from multiple public databases and outputs it in CSV format. This significantly reduces the effort of manual data collection.

PythonBioinformaticsData Processing

todo-go-api

TODO application API implemented in Go.

GoAPIGinGormPostgreSQLDocker

Others

Blog about Investment and Programming

A blog that focuses on the intersection and fusion of investment and programming. Written in Japanese.

BlogInvestmentProgrammingFinanceTechnology

Blog: Reading Watching Something

A blog where I summarize my thoughts on books, movies, and other topics.

BlogEnglishWriting

Contact Me

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GitHub X