This role has closed 1w ago. It is no longer on Twitter's board, so there is nothing left to apply to. The posting is kept here because you saved it or opened it; it is a record, not an offer.

Verified by our engine · Posted +6mo ago

Twitter

Mobile iOS Engineer

Twitter · Product

London

Mid-level

MobileiOSgRPCRustSwift

Last seen 1w ago

Posted
+6mo ago

Posted on 19 February 2026

Workplace
Not specified

Work model not stated

Salary
£107k – £262k

Range published by Twitter

Visa sponsorship
Not specified

Visa sponsorship details unknown

This role has closed. It's kept as a record — see Twitter's open roles or the similar live roles below.

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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.

MOBILE IOS ENGINEER

We’re seeking an exceptional iOS engineer to join a small, high-impact team dedicated to creating the world’s most valuable AI application, judged by the impact it delivers to users. You’ll shape cutting-edge mobile experiences, blending technical mastery with product brilliance.

RESPONSIBILITIES:

Dream up and craft delightful, intuitive user experiences that redefine how people interact with AI on mobile

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 AI researchers and engineers to deploy state-of-the-art models globally

BASIC QUALIFICATIONS:

Experience with Swift, including SwiftUI and UIKit

PREFERRED SKILLS AND EXPERIENCE:

Proficient in performance optimization—memory, CPU, GPU—using low-level tools to deliver blazing-fast systems

Experience in designing and shipping intuitive, pixel-perfect mobile UIs that redefine how users interact with AI

Skilled in concurrency and reactive programming (Combine) for responsive, real-time apps

Built high-throughput integrations with APIs (REST, gRPC) 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

Deep expertise in the Apple ecosystem and related development tools

Rust for working with our backend components

AVFoundation for real-time audio processing

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

Sharp product sense, with an ability to empathize with users, anticipate their needs, and translate that into features that delight and deliver value

COMPENSATION AND BENEFITS:

£107,000 - £262,000 GBP

Base salary is just one part of our total rewards package at SpaceXSI, which also includes equity, comprehensive healthcare and dental coverage, cash plan, income protection, life insurance, and various other discounts and perks.

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

About Twitter

X's (formerly Twitter's) European postings now route through xAI's own board and are concentrated in London and Dublin. Worth noting this is the merged X/xAI entity's hiring, not a standalone Twitter career site anymore.