About Me
Seiichi Arai
Hello – I'm Seiichi, a software developer with a master's degree in Information and Electrical Engineering. After graduating, I spent a year in Australia on a working holiday visa, traveling extensively before launching my engineering career in 2016. Since then, I've contributed to a wide range of projects at several companies. In 2022, I relocated to Germany to join Classmethod Germany under the EU Blue Card. In 2024, I also obtained a permanent residence permit (Niederlassungserlaubnis) in Germany. Additionally, in July 2024, I co-founded a company in Japan with my brother. With more than 10 years of hands-on experience, I specialize in Software Development and DevOps, providing tailored solutions to meet each client's unique needs.
Skills
Technical Skills
Software Development, DevOps, SRE
C++, Rust, Go, Java, Kotlin, TypeScript, Python
Languages
- Native Japanese
- Business English
- Elementary German (telc Deutsch B1)
Certifications
Google Cloud Certified:
Careers
Erstech LLC
Jul 2024 - PresentFounder
Org-chart SaaS
Tech Stack：
Hono, Next.js, Prisma, React Flow, TypeScript, Cloudflare Workers, Cloudflare D1
Description：
A SaaS platform for easy creation and management of organizational charts. Implemented real-time collaboration features enabling multiple users to edit simultaneously. The organization charts can be hosted on the site and used for recruitment web pages.
Partner-relationship Management App
Tech Stack：
Django, Python, Terraform, Google Cloud Run, Google Cloud SQL(PostgreSQL)
Description：
An application to streamline partner relationship management. Implemented features for project progress tracking, easy communication with partners, document sharing, and analysis of partner performance in dashboards.
Edge Surveillance System
Tech Stack：
Raspberry Pi, Camera, Python, Cloudflare Workers, Soracom
Description：
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Classmethod (Europe) GmbH
Jul 2022 - PresentProduct Development Team
Cross-service Communication Platform
Tech Stack：
Event-driven Architecture, Amazon EventBridge, Outbox Pattern, CloudEvents
Description：
Designed and built an event-driven communication platform connecting multiple services. Adopted Amazon EventBridge as the central event bus, applied the outbox pattern to guarantee reliable event delivery, and standardized event schemas with CloudEvents to enable loosely coupled, scalable inter-service integration.
Identity and Access Management Renewal
Tech Stack：
OAuth2.0, RBAC, ABAC
Description：
Identity and access management system renewal project. Replaced legacy Spring Security Authentication and access control with OAuth2.0 and RBAC/ABAC.
API Backend Replacement
Tech Stack：
Kotlin, Spring Boot, JPA, Aurora MySQL
Description：
Backend system modernization project. Adopted Kotlin and Spring Boot to improve performance and maintainability of the system.
E-mail Batch-job System
Tech Stack：
Rust, AWS CDK, AWS Lambda, AWS SES
Description：
Development of a large-scale email delivery system. Achieved high-performance and reliable processing using Rust, with infrastructure as code implementation using AWS CDK.
Development & Consulting Team
Web-app AWS Re-platform
Tech Stack：
Cloud-native Architecture, Containerization, Terraform, AWS ALB, AWS ECS, Amazon Aurora Serverless, Amazon ElastiCache, NewRelic
Description：
Migration of the systems to cloud-native architecture. Enhanced portability through containerization, implemented auto-scaling, and established comprehensive monitoring systems.
Heavy-machinery Data Collection System
Tech Stack：
Cloud-native Architecture, ETL, REST API, Python, FastAPI, AWS Lambda, Aurora Postgres, Serverless Framework
Description：
A system for collecting and analyzing data from heavy machinery. Implemented data collection, ETL processes, and API development.
Factory Monitoring & Visualization
Tech Stack：
PLC, NestJS, React, WebSocket, Node.js, C/C++, S7 Protocol
Description：
Real-time monitoring and visualization system for factory production lines. Implemented PLC data collection, WebSocket-based real-time updates, and interactive dashboards.
Classmethod Inc.
Contract Development Team
Apr 2018 - Jun 2022Microservice System
Tech Stack：
Clean Architecture, Microservices, gRPC, OAuth 2.0, Go, Amazon ALB, AWS ECS, Amazon Neptune, Auth0
Description：
System based on microservices architecture. Designed and implemented inter-service communication, authentication/authorization, and data persistence layer.
Web-app AWS Re-platform (Infrastructure)
Tech Stack：
Terraform, AWS ALB, AWS ECS, AWS RDS, Amazon ElastiCache
Description：
Migration of web application infrastructure to AWS. Implemented Infrastructure as Code, ensured high availability, and performed performance tuning.
Front-end Application Development (PoC)
Tech Stack：
React, GraphQL, AWS Amplify, AWS CDK
Description：
Development of modern front-end development environment. Implemented the AWS resource monitoring dashboard using React and GraphQL.
Agricultural IoT System
Tech Stack：
MQTT, REST API, Python, AWS SAM, AWS IoT, AWS Lambda, DynamoDB, Soracom
Description：
IoT system for agriculture. Implemented sensor data collection and API.
Connected-vehicle IoT Platform
Tech Stack：
MQTT, REST API, Python, AWS SAM, AWS IoT, AWS Lambda, DynamoDB
Description：
IoT platform for collecting and analyzing vehicle data. Implemented real-time tracking, driving data analysis.
Factory Monitoring Data Pipeline
Tech Stack：
PLC, MQTT, Soracom, ETL, Python, AWS IoT, AWS Lambda, DynamoDB
Description：
Data pipeline for collecting and processing factory sensor data. Implemented real-time data processing, data transformation, and persistence features.
Works Applications Co., Ltd.
Site Reliability Engineering Team
Dec 2016 - Mar 2018AWS Research & POC
Tech Stack：
Amazon Aurora MySQL, Serverless Framework, Node.js
Description：
Validation of new AWS technologies and prototype development. Conducted serverless architecture evaluation, performance testing, and cost analysis.
DevOps
Tech Stack：
System Monitoring, CI/CD
Description：
Established system monitoring infrastructure and CI/CD pipelines. Implemented alert configurations and automated deployment flows.
Tecnoplus Inc.
Development Team
Apr 2016 - Sep 2016Advertising-management Tool Development
Tech Stack：
C++, Database Migration, Troubleshooting, Sakura VPN
Description：
Development and maintenance of advertising management tool. Responsible for database migration, performance optimization, and troubleshooting.
Recent Blogs
Building inter-service integration using the Outbox pattern with Debezium + Amazon MSK
How Spring MVC Implements Suspend Functions
Understanding Kotlin Coroutines: A Personal Deep Dive
Spring Boot + Micrometer: Metrics to Send to CloudWatch Metrics and Configuration Method
How to Remap CapsLock to Conversion Key on Cosmic Desktop
Showcase
Djangoで組織とユーザーの権限管理をやってみよう / How to Manage Organization and User Permissions with Django
AWS Glueを使った Serverless ETL の実装パターン / How to Implement Serverless ETL with AWS Glue
イマドキ!ユースケース別に見る AWS IoT への接続パターン / AWS IoT Connection Patterns
Djangoで組織とユーザーの権限管理をやってみよう / How to Manage Organization and User Permissions with Django
AWS Glueを使ったサーバーレスETLの実装方法を徹底解説 / How to Implement Serverless ETL with AWS Glue
ソフトウェアデザイン 2019年12月号 / Software Design December 2019
Honors & Awards
2021 APN AWS Top Engineers (Japan)