Senior iOS Engineer, App Platform

Whatnot•Los Angeles, CA

2d•$210,000 - $230,000•Hybrid

About The Position

Whatnot’s App Platform team builds the shared client infrastructure that product teams use across iOS, Android, and web. The team owns the foundations that help product teams move quickly while maintaining quality, including app stability, the Whatnot Design System, localization, core components, and shared architecture. The Senior iOS Engineer will design and maintain core app architecture and shared components, strengthen networking, real-time, and persistence layers, and lead stability and performance improvements. The role partners with product teams to shape scalable designs, solve technical problems, and provide documentation and guidance for adopting platform work. It also improves developer productivity through build, CI, test, and release tooling and builds observability to catch regressions. The role offers flexibility to work from home or from a global office hub, but team members must live within commuting distance of the New York, Seattle, San Francisco, or Los Angeles hub. Employees are expected to use Whatnot as both a buyer and a seller.

Requirements

Bachelor’s degree in Computer Science, a related field, or equivalent practical experience.
At least 6 years of professional iOS engineering experience, including meaningful experience in infrastructure, architecture, or platform work.
Deep expertise in Swift and iOS fundamentals, including the runtime, memory management, Swift Concurrency and GCD, and the app lifecycle.
A track record of measurably improving stability or performance, such as crash-free rate, launch time, or hang rate.
Strong partnership skills, including treating product engineers as customers, building cross-team trust, and translating their needs into platform priorities.
Experience designing APIs and frameworks for other engineers, with sound judgment about abstraction, migration paths, and adoption.
Comfort using profiling and debugging tools such as Instruments, crash symbolication, and memory graphs.

Nice To Haves

Real-time or media experience, such as WebSockets, AVFoundation, or live video.
Experience with client-side experimentation, feature-flagging, or analytics infrastructure.
Experience scaling a large iOS codebase or team, including modularization, build systems such as Bazel, Tuist, or SPM, or CI/CD.
Experience with GraphQL clients, offline and caching strategies, or local persistence such as Core Data, SQLite, or GRDB.
Contributions to open-source iOS libraries or tooling.

Responsibilities

Design and maintain core app architecture and shared components, including modularization, dependency management, navigation, and patterns used by product teams.
Build and harden networking, real-time, and persistence layers supporting live video, chat, and bidding.
Lead stability and performance improvements, including crash and hang reduction, app launch time, memory use, scrolling, and video performance.
Partner with product teams as an internal consultant, shaping scalable designs, resolving difficult technical problems, and providing documentation and adoption guidance.
Ensure platform infrastructure enables product teams to ship features quickly and safely.
Improve developer workflows, including build times, CI, test infrastructure, and release tooling.
Build observability, including crash reporting, performance monitoring, and alerting, to catch regressions before users do.

Benefits

Generous holiday and time-off policy.
Medical, dental, and vision insurance options.
Work-from-home support.
Home-office setup allowance.
Monthly cell phone and internet allowance.
Care benefits.
Monthly wellness allowance.
Annual childcare allowance.
Lifetime family-planning benefit, such as adoption or fertility expenses.
401(k) offering for Traditional and Roth accounts in the US, with employer match up to 4% of base salary; pension plans internationally.
Monthly allowance to use Whatnot as a buyer and seller.
16 weeks of paid parental leave plus one month of gradual return to work; company leave allowances run concurrently with country leave requirements, which take precedence.