Senior iOS Engineer, App Platform

🚀 Join the Future of Commerce with Whatnot!

Whatnot is the largest live shopping platform in North America and Europe to buy, sell, and discover the things you love. Whether it's trading cards, fashion, electronics, or live plants, our sellers are building real businesses across hundreds of categories. We're building live commerce at a scale that's never been done in the West, and there's no playbook to copy. The people here are shaping how an entirely new industry develops.

As a remote co-located team, we're inspired by our values and anchored in hubs across the US, UK, Ireland, Poland, Germany, and Australia. We move fast, stay close to our users, and focus on the work that drives the most impact.

We're one of the fastest growing marketplaces and were recently named the #1 Best Startup Employer in America by Forbes. Check out the latest Whatnot updates on our news and engineering blogs and join us as we enable anyone to turn their passion into a business and bring people together through commerce.

💻 Role

App Platform is Whatnot's client infrastructure team, building the consistent, reliable foundation that every product team builds on top of across iOS, Android, and web. Rather than owning a single feature surface, the team pushes technical boundaries so product pods can move fast without sacrificing quality — owning things like app stability, the Whatnot Design System, localization, core components, and the shared architecture that keeps our apps performant and consistent at scale.
What you'll do

• Design and maintain the app's core architecture and shared components: modularization, dependency management, navigation, and the patterns product teams build on

• Build and harden the networking, real-time and persistence layers behind live video, chat and bidding

• Lead stability and performance work: crash and hang reduction, app launch time, memory, scroll and video performance

• Partner closely with product teams as an internal consultant: shape scalable designs early, unblock them on hard technical problems, and write the docs and guidance that help them adopt platform work

• Make sure our infrastructure lets product teams ship features fast and safely

• Speed up the developer loop: build times, CI, test infrastructure, and release tooling

• Build observability (crash reporting, performance monitoring, alerting) so we catch regressions before users do

We offer flexibility to work from home or from one of our global office hubs, and we value in-person time for planning, problem-solving, and connection. Team members in this role must live within commuting distance of our New York, Seattle, San Francisco or Los Angeles hub.

👋 You

People who do well at Whatnot tend to be comfortable figuring things out as they go, biased toward action, and genuinely curious about what they're building. They care more about outcomes than credit and stay close to the product and the people using it.

• Bachelor’s degree in Computer Science, a related field, or equivalent practical experience.

• 6+ years of professional iOS engineering experience, including meaningful time on infrastructure, architecture, or platform work

• Deep expertise in Swift and iOS fundamentals: the runtime, memory management, concurrency (Swift Concurrency and GCD), and the app lifecycle

• A track record of measurably improving stability or performance, for example crash-free rate, launch time or hang rate

• Strong partnership skills: you treat product engineers as your customers, build trust across teams, and can turn their needs into platform priorities

• Experience designing APIs and frameworks that other engineers use, with good judgment about abstraction, migration paths and adoption

• Comfort with profiling and debugging tools such as Instruments, crash symbolication, and memory graphs

• Bonus:

  • Real-time or media experience: WebSockets, AVFoundation, live video

  • Experience with experimentation, feature-flagging, or analytics infrastructure on the client

  • Experience scaling a large iOS codebase or team: modularization, build systems (Bazel, Tuist, SPM), or CI/CD

  • Experience with GraphQL clients, offline and caching strategies, or local persistence (Core Data, SQLite, GRDB)

  • Contributions to open-source iOS libraries or tooling

🎁 Benefits

• Generous Holiday and Time off Policy

• Health Insurance options including Medical, Dental, Vision

• Work From Home Support

  • Home office setup allowance

  • Monthly allowance for cell phone and internet

• Care benefits

  • Monthly allowance for wellness

  • Annual allowance towards Childcare

  • Lifetime benefit for family planning, such as adoption or fertility expenses

• Retirement; 401k offering for Traditional and Roth accounts in the US (employer match up to 4% of base salary) and Pension plans internationally

• Monthly allowance to dogfood the app

  • All Whatnauts are expected to develop a deep understanding of our product. We're passionate about building the best user experience, and all employees are expected to use Whatnot as both a buyer and a seller as part of their job (our dogfooding budget makes this fun and easy!).

• Parental Leave

  • 16 weeks of paid parental leave + one month gradual return to work *company leave allowances run concurrently with country leave requirements which take precedence.

💛 EOE

Whatnot is proud to be an Equal Opportunity Employer. We value diversity, and we do not discriminate on the basis of race, religion, color, national origin, gender, sexual orientation, age, marital status, veteran status, parental status, disability status, or any other status protected by local law. We believe that our work is better and our company culture is improved when we encourage, support, and respect the different skills and experiences represented within our workforce.