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Staff Back-end Engineer (Search & Discovery)

Location Seoul, South Korea


Team Overview  

The Recommendation team is responsible for Coupang’s related product recommendation, personalized gateway, widget ranking, and product review quality. Related product recommendation is a fast-growing area and we are continuously improving recommendation quality to help more and more customers find the best products for them. We have also started investing in personalized Gateway, aiming to build one of the best e-commerce discovery experiences. We use the state of the art Machine Learning and Deep Learning technologies, and we continuously innovate and build highly scalable systems to support the growing business and customer engagement. 


About the Role  

As a Staff Backend Engineer for Recommendations, you will be responsible for the design, development and maintenance of the end-to-end Recommendation ecosystem. This encompasses our online ranking system, multiple data pipeline that produces the candidates and features (offline and online) used across our different ranking logics, a serving system that produces content for most of Coupang app. You will need to collaborate closely with the Silicon Valley team that shares ownership of the system. In a controlled environment, run experiments to validate and launch any features that would improve the customer experience. 


Key Responsibilities:  

  • Own the Recommendation service, one of the most critical for Coupang to make sure we are wowing customers constantly. 
  • Collaborate tightly with the Silicon Valley team to co-build a world class recommendation system 
  • Knit across teams by collaborating with product managers and designers and other functions to build holistic experience that's right for Coupang users. 
  • Lead each step of the product development process, from ideation to implementation to release; from rapidly prototyping, running A/B tests, to architecting and building solutions that can scale to support millions of users. 
  • Contribute best-in-class programming skills to develop highly innovative consumer-facing mobile products 
  • Mentor and grow engineers on the team 



  • Bachelor's degree in Computer Science or Computer Engineering or electrical/electronic engineering, mathematics or equivalent 
  • 5+ years of relevant industry experience with distributed systems, transactional datastores, and systems programming 
  • 5+ years of solid work with fundamental algorithms, system design, and large distributed systems 
  • 5+ years of coding experience in one of the following: with: C++, Java, Python, Scala 
  • Experience in building and owning critical user-facing API platform and corresponding backend data systems, and solving complex design, scaling, latency, or performance problems in high-volume low-latency distributed systems 
  • Strong communication skills 


Preferred Qualifications:  

  • Professional Korean proficiency 
  • Master's degree in Computer Science or Computer Engineering or related science majors. 
  • Industrial experience working with online serving system working at scale 
  • Write robust and efficient code using Java with unit and integration tests 
  • Experience in distributed processing using EMR, Spark, Hive, or other big data frameworks 
  • Experience in Stream-processing systems (Kafka, Storm, Spark-Streaming or equivalent) 
  • Excellent communicator with great listening skills, growth mindset and can-do attitude 


Recruitment Process & Others  


Recruitment Process   

  • Application Review - Phone Interview - Onsite (or Virtual Onsite) Interview – Offer   
  • The exact nature of the recruitment process may vary according to the specific job and may be changed due to scheduling or other circumstances.   
  • Interview schedules and the results will be informed to the applicant via the e-mail address submitted at the application stage.   


Details to Consider   

  • This job posting may be closed prior to the stated end date for application if all openings are filled.      
  • Coupang has the right to rescind an offer of employment if a candidate is found to have submitted false information as part of the application process.      
  • Coupang does not discriminate against disabled applicants or those with veteran status. We are proud to offer equal opportunities for all applicants.   
  • Job titles and responsibilities may be subject to change depending on the candidate’s overall experience, etc. This will be communicated to the candidate at the appropriate time before the offer.  


Privacy Notice   


Document Return Policy (This notice MUST be included in a job posting in Korea only to comply with the Fair Hiring Procedure Act.)   

  • This notification is given pursuant to Article 11 (6) of the Fair Hiring Procedure Act.    
  • A job applicant, who has applied but not been finally selected for a position at Coupang (the “Company”), may request the Company to return his/her hiring documents submitted pursuant to the Fair Hiring Procedure Act.  However, this will not apply where the hiring documents were submitted via the website of the Company or e-mail, or where the job applicant submitted those documents voluntarily without a request from the Company.  In addition, if the hiring documents were destroyed due to a natural disaster or any other reasons not attributable to the Company, such documents will be deemed to have been returned to the job applicant.   
  • A job applicant who wishes to request the return of his/her hiring documents pursuant to the main sentence of paragraph 2 above should fill out a “Request for Return of Hiring Documents” [Annex Form No. 3 in the Enforcement Rule of the Fair Hiring Procedure Act] and submit the request to the Company (Coupang Recruiting Team, Tower 730, 570 Songpa-daero, Songpa-gu, Seoul). In such case, within fourteen (14) days from the date of identifying the receipt of the request, the Company will send the hiring documents to the job applicant’s designated address via registered mail.  Please be informed that the job applicant is required to pay the postage on the registered mail.   
  • In preparation for a job applicant’s request for the return of hiring documents pursuant to the main sentence of paragraph 2 above, the Company shall retain the original hiring documents submitted by the job applicant for 180 days from the completion of the recruiting process.  If no request is made until the end of this period, all of his/her hiring documents will be destroyed immediately in accordance with the Personal Information Protection Act.  


Equal Opportunities for All  

Coupang is an equal opportunity employer. Our unprecedented success could not be possible without the valuable inputs of our globally diverse team.