Wonjoon Seol
About Wonjoon Seol
Wonjoon Seol is a Back End Developer at Delivery Hero in Seoul, South Korea, with experience in data science and technology analysis.
Current Position at Delivery Hero
Wonjoon Seol works as a Back End Developer at Delivery Hero in Seoul, South Korea. He has developed the entire logistics backend from scratch using an event-driven architecture as part of the Dispatch Squad. He created a dispatch engine that matched 2 million orders to 7,000 riders per hour per delivery zone. He also worked with rider GPS coordinates using FastAPI, MongoDB (Beanie), and Elasticache for vendor and customer geofences. Additionally, he created a dispatch simulator using Simpy to evaluate the performance of the dispatch engine.
Previous Internships and Roles
Before joining Delivery Hero, Wonjoon Seol was a Data Science Intern at the Centre for Urban Science and Progress London in 2019. Prior to that, he interned as a Technology Analyst at Goldman Sachs for 3 months in 2018. He also gained experience as a Research Assistant Intern at King's College London for 5 months the same year. Early in his career, he worked as a Research Assistant at Bank of America Merrill Lynch for 2 months in Seoul, Korea in 2008.
Technical Contributions and Projects
Wonjoon Seol has made significant technical contributions while working at Delivery Hero. He developed a data pipeline responsible for data consistency and streaming data to a data lake in the Platform Ops Squad. He also developed a fault-tolerant, lightweight custom login backend MSA using the Oauth2.0 protocol, achieving Read-only 70k and Write 36K RPM with a mean 7ms latency. Additionally, he managed AWS API Gateway, connecting multiple MSAs in the system using AWS-CDK. He addressed security issues by fixing CSRF, HSTS headers, and other vulnerabilities on a Django legacy monolith. He used Locust to create an end-to-end automated load test tool to evaluate the performance of production services daily.