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Senior Software engineer, iOS (Mobile Enablement) - Mercari

Salary not provided

SwiftiOS
English: Fluent
Mercari

Senior Software Engineer, iOS (Mobile Enablement)

  • Employment Status: Full-time
  • Work Hours: Full Flextime (no core time)
  • Office: Roppongi

This position requires English language ability. JD is available in English only. 本ポジションは日本語JDの用意がありません。

Team Mission

The Mobile Enablement team transforms mobile development into a seamless, automated, and cross-platform ecosystem. Our mission is to deliver innovative features and user experiences to maximize product-facing impact. We simplify engineering workflows, reduce repetitive tasks through automation/AI, and enable broader collaboration across teams.

By streamlining coding, testing, releases, and operations, we accelerate innovation and scalability, ensuring mobile development keeps pace with business needs. Join us to redefine how we build and deliver the mobile experience!

As an iOS engineer, you will work on building features with our machine learning, backend, and infrastructure members as well as collaborating with other feature-owner iOS engineering teams.

Tech Stack

  • iOS Development: Swift, SwiftUI, Swift Concurrency, Swift Testing
  • Build & Tooling: Bazel, fastlane, Xcode
  • API & Data: Protocol Buffers
  • AI Tools: Claude Code, Codex, Cursor
  • CI/CD: GitHub Actions

Work Responsibilities

  • Design, implement, and maintain high-quality iOS features using Swift and modern iOS frameworks.
  • Own end-to-end feature development, from requirements definition through architecture, implementation, testing, and release.
  • Lead architectural design for complex features and system components, ensuring maintainability, scalability, and reliability.
  • Optimize app performance, startup time, memory usage, and stability across diverse devices and OS versions.
  • Work closely with machine learning, backend, infrastructure, product, and design teams to deliver seamless mobile experiences, as well as other feature-owner iOS engineering teams.
  • Contribute to and evolve the mobile platform, SDKs, and shared modules used across teams.
  • Drive high code quality through code reviews, automated testing, CI/CD improvements, and rigorous documentation.
  • Champion engineering best practices and contribute to guidelines and standards across Client Engineering.
  • Stay current with the latest developments in iOS, Swift, UIKit, SwiftUI, concurrency, and mobile architecture patterns.
  • Bring innovative ideas to improve user experience, developer experience, and operational efficiency.
  • Take ownership of initiatives that span multiple teams, driving alignment and technical decision-making.
  • Mentor junior and mid-level engineers, helping strengthen the overall technical capabilities of the team.

Unique Challenges

  • Develop iOS features for AI-driven solutions that leverage vast data assets, creating high-impact user experiences for tens of millions of users.
  • Deliver highly performant and reliable functionality in a fast-paced environment with complex product requirements.
  • Bridge consumer-grade UX expectations with robust engineering architecture and infrastructure.
  • Influence platform-wide technical strategy, shaping the future direction of the mobile ecosystem.
  • Lead cross-functional efforts in ambiguous problem spaces where user needs and technical constraints must be balanced.

Qualifications

Required Experience/Skills

  • Shared belief in the mission and values of the organization.
  • Bachelor’s degree in Computer Science, Engineering, or equivalent practical experience.
  • Strong proficiency in Swift and iOS development frameworks (UIKit, SwiftUI, Combine, Foundation).
  • Solid understanding of mobile architecture patterns (MVC, MVVM, Clean Architecture, VIPER, etc.).
  • Demonstrated experience with large-scale mobile applications and complex codebases.
  • Experience integrating with backend APIs and asynchronous/concurrent programming.
  • Strong analytical and problem-solving skills; ability to navigate ambiguity.
  • Excellent communication skills and ability to explain technical concepts clearly.
  • Passion for building user-facing mobile products.

Preferred Experience/Skills

  • Experience with large-scale mobile apps serving millions of users.
  • Expertise in performance optimization, instrumentation, and mobile observability (e.g., crash analysis, metrics).
  • Experience with SwiftUI, concurrency (async/await), and modern iOS platform capabilities.
  • Contributions to open-source iOS projects or active involvement in the mobile community.
  • Experience driving technical initiatives across multiple teams or owning platform-level components.
  • Familiarity with CI/CD for mobile, automated testing frameworks, and release management.
  • UI/UX sensitivity and an eye for detail in crafting polished user experiences.

Language

  • English: Independent (CEFR B2) Required
  • Japanese: Independent (CEFR B2) Optional

For details about CEFR, see here.

Learn More

Recruiting Process

  • Application screening
  • Skill assessment (via HackerRank/GitHub for engineering positions)
  • Interview(s)
  • Reference check
  • Offer

Learn more about our recruiting process here.

Equal Opportunity Hiring

We work to realize a world in which no one’s potential is limited by their background and everyone has the opportunity to freely create value. We believe Inclusion & Diversity is essential for us to achieve our mission.

This extends to our hiring practices as well. We are committed to eliminating discrimination based on age, gender, sexual orientation, race, religion, physical disability, and other such factors so that anyone who shares our mission and values can join us.

For more details, please read our I&D statement.

Please read and acknowledge our Privacy Policy prior to submitting your application.

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