xAI

Sr. Mobile iOS Engineer

Posted 3 Hours Ago

Be an Early Applicant

2 Locations

In-Office

200K-375K Annually

Senior level

Information Technology

The Role

Build and improve the X iOS app, delivering intuitive, high-performance user experiences and complex features end to end. Responsibilities include technical and product decision-making, pixel-perfect UI development, performance optimization, quality ownership, A/B testing, issue resolution, and collaboration with design, backend, Android, and web teams. The role also involves integrating APIs and AI model outputs and deploying scalable features to the App Store.

Summary Generated by Built In

SpaceX was founded under the belief that a future where humanity is out exploring the stars is fundamentally more exciting than one where we are not. Today, SpaceX is actively developing the technologies to make this possible, with the ultimate goal of making life multiplanetary and expanding consciousness to the stars.
SpaceXSI is building Super Intelligence to help humanity understand the universe. Our teams are building the full Super Intelligence stack: from our Colossus supercomputers, to Grok models, to our suite of applications, including Grok Bot, Grok Build, Grok Imagine, Grok Voice, and X. We're creating a powerful flywheel where more compute trains better models, better models power more useful products, and what we learn from people using those products shapes what we build next.

SR. MOBILE IOS ENGINEER

We're seeking an exceptional iOS engineer to join a small, high-impact team building X for iOS, the app millions of people use every day to see what's happening and join the global town square. You’ll work in a fast paced environment and take ownership of constantly improving the app; from groundbreaking new features to micro optimizations.

RESPONSIBILITIES:

Craft delightful, intuitive user experiences that redefine how people interact with the app
Obsess over every pixel, animation, and interaction, ensuring the experience feels magical and seamless
Build blazing-fast, highly performant systems where every millisecond counts
Drive technical and product decisions, collaborating with designers, backend, android and web engineers
Own the quality of the products you build - including running a/b tests, finding issues, and proactively making improvements
Be proactive in finding ways to improve the app - from user feedback and from your own daily experience on the app

BASIC QUALIFICATIONS:

Experience in Swift and UIKit

PREFERRED SKILLS AND EXPERIENCE:

Deep expertise in the Apple ecosystem and related development tools
Track record of shipping standout apps or standout features within apps
Deep expertise in iOS development, particularly with Swift. We seek individuals who operate at the highest levels of their craft
Excel at delivering results swiftly, often in a fraction of the time others require. Speed is a core value at SpaceXSI—we must act decisively to succeed
A sharp product sense, with an ability to empathize with users, anticipate their needs, and translate that into features that delight and deliver value
Proficient in performance optimization—memory, CPU, GPU—using low-level tools to deliver blazing-fast systems
Experienced in designing and shipping intuitive, pixel-perfect mobile UIs that redefine how users interact with UI’s
Skilled in concurrency and reactive programming (Combine) for responsive, real-time apps
Built high-throughput integrations with APIs or AI model outputs, ensuring seamless data flow.
Capable of owning complex features end-to-end, from architecture to App Store deployment, with a focus on speed and scalability

COMPENSATION AND BENEFITS:

$200,000 - $375,000 USD

Base salary is just one part of our total rewards package at SpaceXSI, which also includes equity, comprehensive medical, vision, and dental coverage, access to a 401(k) retirement plan, short & long-term disability insurance, life insurance, and various other discounts and perks.

SpaceXSI is an equal opportunity employer. For details on data processing, view our Recruitment Privacy Notice.

Skills Required

Experience with Swift
Experience with UIKit
Deep expertise in the Apple ecosystem and related development tools
Track record of shipping standout apps or standout app features
Deep expertise in iOS development, particularly with Swift
Ability to deliver results swiftly
Strong product sense and ability to translate user needs into valuable features
Proficiency in performance optimization across memory, CPU, and GPU using low-level tools
Experience designing and shipping intuitive, pixel-perfect mobile user interfaces
Experience with concurrency and reactive programming using Combine
Experience building high-throughput integrations with APIs or AI model outputs
Ability to own complex features end to end, from architecture through App Store deployment

xAI Compensation & Benefits Highlights

The following summarizes recurring compensation and benefits themes identified from responses generated by popular LLMs to common candidate questions about xAI and has not been reviewed or approved by xAI.

Healthcare Strength — Healthcare is described as comprehensive, including medical, dental, vision, mental health support, and fertility benefits. Additional protections such as disability and life insurance, plus HSA/FSA options, are also outlined.
Equity Value & Accessibility — Equity is positioned as a core component of total rewards alongside high base salaries for technical roles. Pre‑IPO stock grants are highlighted as enabling participation in potential company growth.
Leave & Time Off Breadth — The package includes flexible or generous PTO, paid holidays, and paid sick days. Company materials also describe flexible vacation policies intended to help manage fast‑paced workloads.