{"$schema":"https://raw.githubusercontent.com/jsonresume/resume-schema/v1.0.0/schema.json","basics":{"name":"Jonghyeon Ham","label":"Founder/CEO @ refresh.cv","image":"https://saywise-production-profilepicturestoragebucket-kbfooccc.s3.amazonaws.com/profile-pictures/37b8f416-8f54-4b76-9a8f-895beebe4b4c/linkedin-1786294217263.jpg","location":{"city":"United States"},"profiles":[{"network":"LinkedIn","username":"jonghyeon-ham","url":"https://linkedin.com/in/jonghyeon-ham"}]},"meta":{"canonical":"https://saywise.com/jhham","version":"v1.0.0","lastModified":"2026-08-09T16:50:19.204Z"},"x_saywise":{"handle":"jhham","pronouns":null,"availability":null,"oneLiner":null,"profileUrl":"https://saywise.com/jhham","markdownUrl":"https://saywise.com/jhham/profile.md","pdfUrl":"https://saywise.com/jhham/resume.pdf","archetype":{"code":"RS-MX","name":"Frontier Artisan","url":"https://saywise.com/sca/011f9c9544b3","rarity":"One of the first Frontier Artisans on Saywise"}},"work":[{"name":"refresh.cv","position":"Founder/CEO","location":"대한민국","url":"https://refresh.cv","startDate":"2024-10-01","summary":"refresh.cv - Drove zero-to-one across product, architecture, full-stack engineering, UX design, data analytics, and GTM/sales - Shipped resume editor with agent-based resume authoring, revision, and feedback - Launched resume scoring and feedback based job description - Delivered resume web templates and resume card components"},{"name":"Viva Republica (Toss)","position":"Server Developer","location":"Gangnam District, Seoul, South Korea","url":"https://toss.im","startDate":"2023-03-01","endDate":"2024-10-01","summary":"Toss Ads - Built and operated ad platform used in 15M+ MAU Toss app for campaign execution, review, and performance - Implemented ad performance ingestion/aggregation (impressions, clicks, plays) with Kafka, Druid, Impala - Implemented real-time CPM/CPC billing; ensured data integrity at scale with local cache + flush pattern - Contributed to settlements, agency commission payouts, and tax invoice issuance - Shipped ad account/group systems and integrated with Toss Business Display Ads product (monthly 10B+ KRW scale) - Contributed to eCPM-based ad recommendation and ranking improvements, driving >1B KRW monthly uplift - Implemented multiple optimization strategies to minimize ad refresh and serving latency, improving both UX and fill rate. - Implemented CPC (cost-per-click) and CPM (cost-per-mille) billing logic end-to-end for our ad serving pipeline. - Built real-time dashboards and alerting to monitor impressions, clicks, and spend in production, catching ad-serving incidents before they impact revenue Live Shopping - Optimized performance with tens of thousands of peak RPS without degrading UX using Local Cache, Redis and Kafka optimizations - Authored article on handling large-scale traffic without adding servers (https://toss.tech/article/monitoring-traffic) Credit Score Board - Built product aligned to financial context and user comprehension Benefits Tab (8M+ DAU) - Shipped Lucky Quiz, Lucky Lottery, Money Alerts, and Weekly Missions - Owned product development and operations from advertiser and user perspectives"},{"name":"트랜스버스(Transverse Inc.)","position":"Co-Founder, Lead Software Developer","location":"대한민국","startDate":"2020-11-01","endDate":"2023-03-01","summary":"founding team; leading product roadmap and led a 10-engineer team Evoclass: real-time video conference platform - Implemented WebRTC SFU with Mediasoup and high-performance socket servers using uWebSockets - Built server orchestrator and demand forecasting to reduce streaming cost and ensure efficiency - Created container-based load testing to guarantee real-time video/audio QoS and performance - Delivered real-time STT and translation via browser-native APIs - Built AI-powered video effects: background blur, virtual background, face morphing Learning Management System - Designed and implemented system architecture - Integrated with the video platform to enable AI-driven learning features"}],"education":[{"institution":"Korea Advanced Institute of Science and Technology","studyType":"Undergraduate in Computer Science","startDate":"2020-03-01","endDate":"2027-02-01"},{"institution":"Korea Digital Media High School","studyType":"High School","startDate":"2017-03-01","endDate":"2020-02-01"}],"projects":[{"name":"Baseweb, Uber","description":"- Fixed an error in the official documentation - Pull Request #4355"},{"name":"neis-counter","description":"- Product Owner & Maintainer - Served 500k users in the last 12 months; used by ~1 in 10 Korean high school students"},{"name":"NeuralAction","description":"- Product Owner & Maintainer - A Real-time and Accurate Gaze Tracking Application for a More Natural Human-Computer Interaction with User Interface"}],"skills":[{"name":"Kotlin"},{"name":"스프링 프레임워크"},{"name":"WebRTC"},{"name":"Backend"},{"name":"Frontend"},{"name":"DevOps"},{"name":"Machine Learning"},{"name":"리서치"},{"name":"파워포인트"},{"name":"자바"},{"name":"C#"},{"name":"C"},{"name":"Python"},{"name":"Flask"},{"name":"PHP"},{"name":"Node.js"},{"name":"MySQL"},{"name":"Docker"},{"name":"아마존 웹 서비스(AWS)"},{"name":"Visual Basic .NET"},{"name":"WPF"},{"name":"Zeplin"},{"name":"Photoshop"},{"name":"Illustrator"},{"name":"After Effect"},{"name":"3D 스튜디오맥스"},{"name":"UI 디자인"},{"name":"UX 디자인"},{"name":"Socket.io"},{"name":"HTML5"},{"name":"CSS"},{"name":"Javascript"},{"name":"JQuery"}],"awards":[{"title":"1st place, OpenResource Hackathon Seoul","date":"2019-12-01","awarder":"Common Computer Inc, AI Network"},{"title":"Talent Award of Korea","date":"2018-11-01","awarder":"Ministry of Education","summary":"- High School Division"},{"title":"Grand Award 4th place, Intel International Science and Engineering Fair (ISEF)","date":"2018-05-01","awarder":"Intel, Society for Science","summary":"- Finalist of South Korea - Grand Award 4th place, Robotics & Intelligent Machines - Neural Action: A Real-time and Accurate Gaze Tracking Application for a More Natural Human-Computer Interaction with User Interfaces"},{"title":"1st, Korea Youth Science Creativity Challenge (ISEF-K)","date":"2018-02-01","awarder":"National Information Society Agency"},{"title":"Gold Medal, Korea Olympiad in Informatics (KOI)","date":"2017-11-01","awarder":"Ministry of Science and ICT"}],"publications":[{"name":"Large-Scale Traffic Without Adding Servers","summary":"Write-up summarizing troubleshooting while building and operating the “Live Shopping” product in the Toss Benefits tab."},{"name":"Rehearsal: Designing Systems for AI Interviews"}]}