Software Engineer, iOS [Internship]

Tokyo, Japan · Student Recruitment · EN/JP


(Japanese follows English)

▼ Our mission

We are always looking for new challenges to help us fulfill our mission to create value in a global marketplace where anyone can buy & sell.

The world is full of objects and services being produced and sold, but many of them are thrown away without people realizing that they might be valuable to someone else, wasting valuable natural resources. To contribute towards eliminating waste, we have launched Mercari, a marketplace where people can buy and sell easily and safely, in Japan and the United States.

Merpay’s mission is to build trust for a seamless society. Our aim is to change the way money is circulated, establish a Merpay that provides all kinds of services, and develop a world where everyone can enjoy peace of mind.

Merpay aims to bring liquidity and innovation to the world of finance, and create new value not just for consumers, but for businesses as well.

▼ Our three values (Go Bold, All for One, Be a Pro)

We work together to create a global marketplace, but the road to this goal is by no means easy. In order for us to make new innovations and take on new challenges that no one has taken before, all of us take ownership of our work and make use of our knowledge so that we can create the best product possible as one team. To achieve this, we all take action based on our three company values (Go Bold, All for One, and Be a Pro).

▼ The goal of the engineering organization

At Mercari, engineering teams always strive to continuously produce significant results. To do this, our organization constantly welcomes changes and new challenges, cooperates and co-creates, is diverse, offers freedom, and encourages all of us to take ownership and make our own decisions. We want to continue taking on new challenges, working together as one team, going bold, and taking ownership so that we can grow individually, while working toward the realization of Mercari’s mission.



世の中では多くのモノ・サービスが生産・販売されていますが、誰かには価値があるのに捨ててしまうなど地球資源の無駄になっていることが多いと私たちは考えています。 「捨てる」をなくすために、個人間で簡単かつ安全にモノを売買できるフリマアプリ「メルカリ」を日本とアメリカで展開しています。




▼ 3つのバリュー(Go Bold, All for One, Be a Pro)

世界的なマーケットプレイスを創るために我々は集まっていますが、この目標への道のりは決して平坦ではありません。まだ誰も挑戦したことのないようなイノベーションや破壊的な創造を起こすため、我々は各自がオーナーシップを持ち、専門的能力を発揮することで、メルカリというチームとして最高のプロダクトを創ります。これを達成するために我々は3つのバリュー(Go Bold, All for One, Be a Pro) という全社員が共有する行動指針のもと行動しています。

▼ Engineering 組織が目指すもの


チーム一丸となり、Go Boldにオーナーシップを発揮して個が成長し、メルカリのミッションの実現に向けた挑戦をし続けていきます。

▼Job Description

Mercari and Merpay are looking for professional iOS engineers who will work on our services, overseeing planning and development. As a large scale app, there are a number of concurrent projects taking place at any time in the development of both versions. Each individual project is handled by a team of roughly 10 members, of which 1~2 are iOS engineers.

The roles of each individual iOS engineer differ based on the project they are associated with, but all positions require cooperation with highly-skilled colleagues in a number of differing engineering fields. No matter what project an individual iOS engineer may be assigned to, their work is guaranteed to have an impact on a very large user base, so a high level of expertise and ownership towards one's work is naturally expected from each member of our team. Example project like:

・Improving the purchasing experience for the US app based on findings from the analytics team

・Carrying out improvements that help guarantee a safe/secure experience for Mercari users

About Merpay, despite still being in the pre-launch phase, there are already a number of projects underway, and each project has a team of around 10 people, 1-3 of whom are iOS engineers. Merpay iOS engineers must be flexible and open-minded, as they will also be involved with integration with the Mercari app, and must communicate with Mercari teams and understand technologies used by Mercari.

We choose our technology stack based on what best matches the needs of our product's current development phase. At the moment we utilize Reactive Programming in an MVVM-based architecture. In addition to feature development and app improvements, we also continuously improve our development process pipeline which includes continuous integration and build deployment automation. As a software engineer at Mercari, you will have many opportunities to improve your skills in a variety of software engineering disciplines. We also strongly encourage participation in the iOS development community, including:

・Speaking at such domestic conferences as: AltConf, iOSCon, try! Swift, iOSDC, etc.

・Writing articles for the Mercari Engineering Blog

・OSS (Open Source Software) contributions

・Type-safe Web APIs with Protocol Buffers in Swift at AltConf 2017

・Dependency Injection in Practice at iOSCon 2017


・The design, development, and improvement of both new and existing features for Mercari and Merpay apps

・Team development in cooperation with product managers, designers, server-side engineers, and QA/test engineers

・Source code improvements and development environment enhancements via automation

・Code review for fellow team members

・Designing and developing SDKs for integration with Mercari

▼ About Mercari & Merpay’s iOS Teams

Mercari and Merpay’s iOS Teams consist of members coming from very diverse backgrounds, featuring an environment buzzing with English conversations.

The development environment allows members to work on the client app as part of a large team, conducting large-scale development on a service used by countless people.

In addition, there are endless opportunities to receive code reviews from highly experienced members and benefit from significant personal growth.

The company proactively provides support to members who wish to participate in international conferences and learn about the latest technology.

▼Technical Environment


・Protocol Buffers












・AltConf, iOSCon, try! Swift、iOSDCといった国内外のカンファレンスでの講演

・Mercari Engineering Blog上での記事執筆

・OSS (Open Source Software) への貢献

・Type-safe Web APIs with Protocol Buffers in Swift at AltConf 2017

・Dependency Injection in Practice at iOSCon 2017







▼メルカリ/メルペイ iOSチームについて

メルカリ/メルペイ iOSチームには様々なバックグラウンドを持った社員が集まっており、英語での会話が飛び交うようなグローバルな環境となっています。






・Protocol Buffers






▼Minimum Requirements

・Shared belief in Mercari and Merpay’s mission and values

・Candidate must be a student over 16 years old

・Experience developing native applications for iOS using Swift/Objective-C

・Knowledge of standard iOS library/frameworks such as UIKit

▼Additional Qualifications

・Experience developing/operating a large scale app

・Experience developing/operating third-party SDKs

・Knowledge regarding performance optimization

・Extensive knowledge of UI development using Storyboards and/or Auto Layout

・Experience with/understanding of reactive programming

・Automation experience using Bitrise, CircleCI, etc.

・Contribution to Open Source projects

▼ Our Ideal Candidate

・A skilled communicator capable of offering valuable insight in team discussions

・Capable of taking on bold challenges and learning from mistakes

・Proactive and capable of thinking independently for the good of the team

・Eager to gain new knowledge and ready to proactively challenge themselves using the newest technologies

▼ Language Ability

・Business level English or Japanese








・3rd party 向けSDKの開発・運用経験


・StoryboardやAuto Layoutを用いたUI開発における深い知識









▼ 言語能力



▼Contract Type




▼Work Hours


 Able to work more than 20 hours per week


・Hourly wage (Salary: Negotiable)











・Full transportation coverage

・Custom PC

・Dual screen if needed

・Visa support

・Accommodation for those who are from outside of Tokyo area






Apply for this job