Staff iOS Engineer, App Platform

About 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.

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

Requirements

• Bachelor’s degree in Computer Science, a related field, or equivalent practical experience.
• 8+ 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.

Qualifications

• 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.

Skills

• 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