Software Engineer, Backend

Tokyo, Japan · Engineering · EN/JP


Mercari’s Backend Team is at a major turning point. The marketplace app, Mercari, has grown at an incredible pace since it was first released, and is now one of the largest C2C platforms in Japan. Recently, Mercari has been diversifying it’s offerings, adding features such as Mercari Channel and Mercari NOW, as well as diving into the services market with Merpay.

This diversification occurs in conjunction with a massive increase in scale (and consequently, performance requirements!), with the Mercari API now handling over 93.8 billion yen per quarter over the last three quarters. We have always focused on creating a scalable system with high maintainability to allow us to keep up with service growth, but as we look towards expanding our services even further, we believe that the next step is to break down our API into microservices.

By switching from a monolithic to a microservice based API, we are investing in technology to create a system and organization that is ready for the future. However, our services will not stop growing while we make these changes. We also need to continue making improvements everyday to provide an even better user experience to our customers. We are aiming to embody the company values of Go Bold and All for One by revolutionizing our system and organization to allow for even greater service growth.

As a Backend Engineer, you will be responsible for building new features for this API, as well as for various measurements and improvements. You will have a wide range of duties, including determining specifications, interface design, database design, code design and class organization, implementation, reviews, measurements, etc. You will also be actively involved in the decision-making process, giving feedback on specifications and other such discussions. We highly value your contributions to the team not just as an engineer, but also in the way you share knowledge/experience (through blogs, lectures, etc.).



これまでモノリシックなAPIとして設計・実装されてきたメルカリAPIをMicroservice化することで、責任範囲を分割し、より拡大に強い形のシステム・組織へと作り変える技術投資をしていきます。ですがもちろん、それを進める間もサービスの歩みは止まりません。お客様により良い体験を提供するため、日々の改善も進めていきます。我々は、システム・組織の大きな変革とサービスの成長の両面に対して、GoBold/All for oneに取り組みを進めています。


▼Job Description

・Development and design of Mercari API and web apps

・Development and design of supporting tools for planning and customer support teams

・Development and design of Microservices that make up the Mercari API






▼Minimum Requirements

・Experience developing/designing web apps with PHP, Go, Java, Python, JavaScript, Ruby,  Perl, etc.

・Experience designing tables and creating queries to efficiently use RDBMS

・Experience developing with a team using Git/GitHub or a similar version control system

▼Additional Qualifications

・Experience developing microservice architecture

・Experience developing apps using gRPC protocols

・Experience with test-driven development using unit test frameworks

・Experience developing web applications using web application frameworks/libraries

・Knowledge of security in relation to web applications

・Experience as a Tech Lead of a development team with several members

・Experience developing with an external API for payment, shipping, etc.

・Experience with project management

・Experience developing large-scale services

  (capable of designing with server load in mind)

・Experience contributing to and/or creating open source software

▼Technical Environment

・Programming languages: PHP, Go, etc.

・Middleware: MySQL, memcached, Nginx, Solr, Docker, Kubernetes, etc.

・Infrastructure: Dedicated servers, Google Cloud Platform

・Other tools: Slack, JIRA, GitHub, Circle CI, etc.


・PHP, Go, Java, Python, JavaScript, Ruby, Perl などによるWebアプリケーションの設計・開発経験

・RDBMSを効率的に利用するためのテーブル設計 / クエリ作成の知識・経験

・Git / GitHubもしくは類似のバージョン管理システムを利用したチームでの開発経験













・開発言語: PHP, Goなど

・ミドルウェア: MySQL, memcached, Nginx, Solr, Docker, Kubernetesなど

・インフラストラクチャ: 専用サーバ・Google Cloud Platform

・その他利用ツール・サービス: Slack, JIRA, GitHub, Circle CIなど


▼Contract Type


 Probationary Period: 3 months (salary same as above)



▼Work Hours

・Fixed working hours 10:00-19:00

 Flex time (core hours 12:00-16:00, 60 minute lunch)


・Annual salary, paid monthly

・Based on your experience, skills and potential

・Reviewed twice a year


・5-day work week (Sat/Sun off)

・National holidays, paid time off, summer/New Year's vacation, congratulatory leave, compassionate leave








 フレックスタイム制度あり(コアタイム:12:00~16:00 [休憩60分] )









・Health insurance

・Incentive program

・Employee stock ownership plan

・Full transportation coverage

・Custom PC

・Dual screen if needed

・Company smartphone

・Visa support

・New Employee Benefits at Mercari「mercibox












Mercari Engineering Blog


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