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Hossein Aghaei

@hosseinaghaei

Backend engineer at Digikala who cut database CPU usage by 40% and built a stock-management microservice serving 50,000+ requests per second.

Belgium

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At Digikala, I traced a live cache-inconsistency fault to MySQL isolation levels across 10+ production databases and helped cut main database CPU usage by 40%. I also built a stock-management microservice serving 50,000+ requests per second.

I rewrote half of the legacy seller-side service and integrated it with a React front end over REST. I also redesigned buy-box selection for 100M+ events per day and optimised auto-pricing and queue processing.

As Engineering Manager & Technical Lead at Digikala, I led a team of up to five engineers, delivered MySQL training to approximately 200 engineers, and built an LLM-powered seller chatbot that cut process time 20x. Earlier at Mohaymen, I implemented distributed request tracing and built a streaming C#/.NET CSV parser.

Experience

Work history, roles, and key accomplishments

Engineering Manager & Technical Lead

Digikala

Jan 2026 - Aug 2026 (7 months)

Led a team of up to 5 engineers owning the price and promotion domain, setting technical direction. Designed and delivered an advanced MySQL training programme to approximately 200 engineers company-wide.

Team Leadership Technical Direction MySQL LLM Chatbot Black Friday Campaigns High Concurrency Systems

Senior Software Engineer

Digikala

Apr 2023 - Dec 2025 (2 years 8 months)

Traced a cache-inconsistency fault to MySQL isolation level and migrated to read-committed, cutting main database CPU usage by 40%. Rewrote 50% of the legacy seller-side service and built a stock-management microservice serving 50,000+ requests per second.

MySQL Query Optimization Microservices React REST Distributed Transactions Change Data Capture PHP Redis Disaster Recovery

Software Engineer

Digikala

Jul 2022 - Mar 2023 (8 months)

Worked on buy-box formula logic, MySQL index design and heavy production query optimisation in the Price and Promotion team.

MySQL Index Design Query Optimization Buy Box

Software Engineer

Mohaymen

Feb 2021 - Nov 2021 (9 months)

Implemented distributed request tracing and logging across services using the Decorator pattern. Built a multi-operational CSV parser in C#/.NET reading a 4 GB file in 8 seconds via streaming and buffered I/O.