Senior iOS SDK Engineer

Role Description

The Mobile team builds the core infrastructure that will power revenue for thousands of mobile apps. At scale, our SDK will run in production apps with hundreds of millions of daily active users, processing billions of ad requests per month. We're a small, high output team committing code daily.

You'll own the critical path. The SDK is the first point of contact between publishers and CloudX's marketplace, so reliability and performance aren't optional. Every line of code you write affects real revenue for real businesses. We move fast, ship often, and measure everything.

As a Senior iOS SDK Engineer, your key responsibilities will be to:

• Collaborate with the product team to design and implement core SDK features
• Build and maintain integrations with third-party ad networks (Meta, Google AdMob, etc.)
• Optimize SDK to be seamless in host apps: minimize startup impact, reduce binary size, manage resources efficiently, and handle errors gracefully without affecting app stability
• Engage directly with publishers to diagnose real-world issues and improve SDK usability, reliability, and integration experience

Qualifications

• Proven experience building and maintaining production iOS apps or SDKs
• Strong proficiency in Objective-C (Swift experience a plus)
• Expert-level understanding of iOS concurrency (GCD, async/await, threading, memory management)
• Deep understanding of iOS internals: runloops, networking, background execution, app lifecycle
• Strong testing and debugging discipline
• A genuine builder: Someone who codes daily, sweats the details, and has shipped complex systems, not just talked about them
• A clear, concise communicator: You can take a messy problem and make it legible, explaining trade-offs to engineers, PMs, and execs without hand-waving
• A startup operator with good instincts: You know when to ship fast, when to slow down, and how to navigate ambiguity without waiting for perfect specs or marching orders
• An owner, not a passenger: You turn loosely defined problems into real solutions, care deeply about whether the product actually works, and use AI as a force multiplier, not a crutch

Requirements

• Experience building developer-facing SDKs or libraries, including documentation, versioning, and integration support (preferred)
• Experience distributing SDKs via CocoaPods / Swift Package Manager / binary frameworks (preferred)
• Cross-platform SDK experience with Flutter, React Native, or Unity development (preferred)
• Mobile advertising experience: Understanding of ad mediation, waterfalls, etc. (preferred)

Benefits

• The annual US base salary range for this role, and other engineering roles, is $150,000 – $300,000
• Equity compensation and top-tier medical, dental, and vision benefits
• A generous hardware budget for a computer, monitor, and other core equipment necessary to work effectively on a remote team
• Flexibility in work hours with minimal synchronous meetings
• No in-office requirement