Senior iOS Engineer, App Platform

📋 Job Overview

🚀 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.

🏢 About Whatnot

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.

🎯 The 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.

✅ Key Responsibilities

• 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

📌 Required Qualifications

• 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

⭐ Desirable Experience

• 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
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.

🛂 Visa & Eligibility

Please note: Whatnot will only contact you through official @whatnot.com email addresses. If you see an email impersonating a Whatnot recruiter, please disregard and report it as spam.