Industry Technology Inc.

Company

Key	Value
Company	Industry Technology Inc.
Employee	30+
Founded	2018
Web Site	https://industrytechnology.co/
Description	Industry Technology is a proptech company that develops enterprise applications for Japan’s largest real estate companies
Location	Tokyo, Japan

Team

Key	Value
Title	CTO / Software Engineer (Backend)
Mission	My mission was to lead the development team as CTO while personally developing the entire backend code from scratch.
Term	2019-04 - 2024-09
Team Size	8
Type	Permanent

Projects

Key	Value
Summary	IT1. I designed SLIs/SLOs and developed custom metrics and tracing to improve reliability, which built customer trust and won us a major enterprise contract.
Situation	We had a chance to introduce our system to one of Japan's largest real estate companies. I realized our operations didn't meet the reliability and performance levels this enterprise customer needed.
Task	My mission was to improve system reliability to meet the strict standards expected by a major enterprise customer.
Action	I designed SLIs/SLOs: I designed them based on Critical User Journeys (CUJs) I set clear reliability targets that matched business needs I implemented metrics and distributed tracing: I implemented custom metrics to track key performance indicators I added distributed tracing to show how requests flow through the system
Result	As a result, the improved system reliability built customer trust. This led to winning a major enterprise contract.
Challenge	A key challenge was defining clear and meaningful SLOs. It was difficult to set goals that genuinely reflected user value, rather than just measuring random numbers.
Solution	To solve this, I ran thorough load tests to see how SLIs behaved during traffic spikes. I used this data to set realistic SLOs. I adjusted them over time as needed.
Learning	I learned that balancing reliability and agility is crucial for meeting customer satisfaction.
Skill	SLI/SLO / Observability / Monitoring / Load Test / Leadership / Difficult Decision

Key	Value
Summary	IT2. I developed a group chat service and notification system that support texts, photos, videos, and PDFs, which helped increase user engagement and productivity.
Situation	A client needed a chat feature within a month deadline for daily business operations and user collaboration. The feature includes sharing texts, photos, movies, and PDFs.
Task	My mission was to develop a complete group chat service and notification system to meet business needs.
Action	I implemented media sharing infrastructure I implemented secure media sharing using S3 with Signed URLs I added a CDN for fast content delivery I built chat and notification system I built an event-driven architecture for efficient notifications I developed the group chat functionality to handle texts, photos, videos, and PDFs
Result	As a result, the new system provided a smooth chat and notification experience. User engagement and productivity improved.
Challenge	A key challenge was the very tight schedule. We didn't have enough time to build a complex WebSocket-based real-time solution.
Solution	To solve this, I extended the existing API using polling for near real-time updates instead of building a WebSocket server.
Learning	I learned that practical solutions often bring business benefits more quickly than technically perfect ones.
Skill	Feature Development / Tight Schedule / Difficult Decision / Event-Driven

Key	Value
Summary	IT3. I solved a performance issue with the database by optimizing indexes and queries, and by using caching, which reduced slow query occurrences by 70%.
Situation	A core feature of the application had repeated slow queries, which hurt user experience. These slow queries caused high CPU and memory usage on the database, especially during peak times.
Task	My mission was to find the root causes of performance problems and optimize queries for better stability and speed.
Action	I optimized database structure: I analyzed query patterns and added the right indexes to speed up data retrieval I implemented query result caching using Redis I improved query efficiency: I rewrote complex queries to eliminate unnecessary table joins I optimized WHERE clauses to use indexes effectively
Result	As a result, these optimizations reduced slow query occurrences by 70%. System performance became stable, especially during peak hours.
Challenge	A key challenge was finding the exact source of slow queries. We had complex data models and complicated query patterns.
Solution	To solve this, I monitored and analyzed distributed tracing data. I found problems and identified bad query paths. I used EXPLAIN statements to analyze query execution plans. I looked for full table scans and poor index usage.
Learning	I learned that tuning the database according to the business characteristics can improve user satisfaction.
Skill	Performance Optimization / Difficult Problem

Key	Value
Summary	IT4. I migrated from monolith to microservices architecture using a BFF layer to ensure no downtime, which improved system scalability and reduced database load.
Situation	The system was initially developed as a modular monolith. Over time, it began to reach its scalability limits. User traffic to key features increased, leading to a higher write load on the central database. This caused a decline in performance.
Task	My mission was to create separate microservices from the main monolithic service to spread the load and improve system scalability.
Action	I developed microservices and migrated I designed and built three microservices for different areas I created Work Diary, Attendance Management, and core Main services I migrated the system to microservices step by step to reduce risk
Result	As a result, the migration successfully spread traffic for core features across separate microservices. This greatly reduced the write load on the main database.
Challenge	A key challenge was doing the migration with no downtime to avoid disrupting users.
Solution	To solve this, I added a Backend-for-Frontend (BFF) layer in front of the new microservices. This let us gradually switch traffic from the monolith to each new service. We achieved a smooth and controlled migration.
Learning	I learned that migrating a system with no downtime requires several times more effort than a typical migration.
Skill	Migration / Microservices / BFF

Key	Value
Summary	IT5. I led the migration from MySQL 5.7 to 8.0 and managed an incident during the process, which improved query performance by 20%.
Situation	The existing MySQL 5.7 database version was reaching end-of-life.
Task	My mission was to smoothly upgrade the database to MySQL 8.0.
Action	I planned the migration I created a detailed, step-by-step migration plan (runbook) I made sure the process was predictable and controlled I migrated I used a blue-green deployment strategy I ensured smooth transition, minimal downtime, and clear rollback path
Result	As a result, we completed the migration to MySQL 8.0. After we stabilized it, overall query performance increased by 20%.
Challenge	A key challenge was that we got an incident during migration, affecting user experience on some service pages.
Solution	To solve this: I quickly detected the issue through our monitoring system. The root cause was a JSON parsing error caused by an accidental data type change in a column. I deployed a hotfix to handle the JSON parsing errors smoothly. This restored service availability. I then changed the affected JSON column types back to their original UNSIGNED definition. This completely fixed the compatibility issues.
Learning	I learned that unexpected issues can happen despite careful preparation, and it's important to respond calmly.
Skill	Incident Response / Migration

Technology

Value	Tag
Go	Backend
gRPC	Backend
MySQL	Backend
PostgreSQL	Backend
Redis	Backend
AWS	Infrastructure
Google Cloud	Infrastructure
Terraform	Infrastructure
Datadog	Monitoring
Prometheus	Monitoring
Next.js	Frontend
React	Frontend
TypeScript	Frontend