Mobile Engineer

Immersum; Remote; GBP 130,000 - 150,000; Full time

Job summary

A leading tech company is seeking a Senior Mobile Engineer / Architect to redefine mobile interactions. This fully remote position requires expertise in Kotlin and Swift to architect performant mobile applications. You'll collaborate with a globally distributed team to ensure reliable performance in mobile experiences while engaging directly with enterprise customers. Ideal candidates have experience in real-time systems, performance optimisation, and a strong communication skill set. Join a high-trust culture focused on autonomy, impact, and competitive compensation.

Benefits

Competitive salary and benefits

Remote-first culture

Opportunities for impact and advancement

Qualifications

• Deep hands-on experience in native mobile development on Android (Kotlin) or iOS (Swift), ideally both.
• Proficiency in Swift and comfort with Objective-C codebases.
• Proven ability to build and scale complex, performance-critical apps for enterprise use.
• Experience with real-time systems and low-latency networking.
• Mastery of performance optimisation tools (Perfetto, Instruments, etc.).
• Excellent communication skills to engage with customers.

Responsibilities

• Architect and build performant Android and iOS apps integrating real-time communication systems.
• Work with enterprise customers to optimise mobile experiences.
• Own the full mobile lifecycle: architecture, modularisation, build pipelines.
• Collaborate with backend and systems engineers for secure, scalable solutions.

Skills

Kotlin

Swift

Objective-C

Real-time systems

Performance optimisation

Networking

Concurrency

CI / CD

Job description

Job Title: Senior Mobile Engineer / Architect (iOS / Android)

Location: Remote – UK

Salary: £130,000 - £150,000

The Company

This isn’t your typical mobile app startup. The company is redefining what’s possible in real-time interaction and remote collaboration, powering zero-download, enterprise-grade screen sharing and co-browsing used by some of the biggest brands in the world. Their technology enables instant, secure, and frictionless experiences between customers and support teams, all in the browser, across devices, and at global scale.

Now they’re bringing that power to mobile, and they’re looking for a world-class Mobile Engineer to help lead the charge across Android and iOS. If you love working close to the metal, care about performance and architecture, and enjoy engaging directly with customers to shape impactful solutions, this is your kind of role.

The Role

You’ll be the technical backbone for mobile engineering within a globally distributed team.

Your work will power customer interactions where milliseconds matter and reliability can’t be compromised.

You will

• Architect and build deeply performant Android and / or iOS apps that integrate with advanced real-time communication systems (WebRTC, low-latency streaming, complex data sync).
• Work directly with enterprise customers, helping them integrate and optimise mobile experiences using your technical insight.
• Own and optimise the full mobile lifecycle : architecture, modularisation, dependency management, build pipelines, and release automation.
• Push the limits of Kotlin, Swift, and the underlying SDKs — profiling, tuning, and rethinking architecture where needed.
• Collaborate cross-functionally with backend, systems, and security engineers to deliver secure, scalable, and high-performing mobile experiences.
• Prototype and benchmark next-generation features in areas like on-device encoding, network optimisation, and secure session management.
• Act as a mobile domain expert — setting technical direction, mentoring others, and influencing long-term product strategy.

You Should Have

• Deep hands-on experience in native mobile development — either Android (Kotlin) or iOS (Swift), ideally both.
• Proficiency in Swift, with comfort reading or maintaining Objective-C codebases for lower-level integrations.
• Proven ability to build and scale complex, performance-critical apps or SDKs, ideally for enterprise or platform use.
• Experience with real-time systems, streaming, or low-latency networking.
• Mastery of profiling, debugging, and performance optimisation tools (Perfetto, Instruments, Systrace, etc.).
• Strong understanding of networking, concurrency, security, and system-level behaviour on mobile.
• Comfort with NDK / C++ integrations, JNI, or Metal where required for performance or low-level system access.
• Excellent communication skills — you can engage confidently with customers and internal stakeholders to deliver the best outcomes.
• Preference for candidates in US time zones, but open globally for the right person.

Tech Stack

• Android : Kotlin, Jetpack Compose, Coroutines, Clean Architecture, Android Architecture Components, Hilt / Dagger, WebRTC, gRPC, Protocol Buffers, NDK / C++, Bluetooth, low-latency networking, Gradle, Espresso, CI / CD (GitHub Actions, Bitrise)
• iOS : Swift, Objective-C, SwiftUI, Combine, UIKit, Core Data, AVFoundation, WebRTC, gRPC, Protocol Buffers, Metal, Bluetooth, Instruments, XCTest, CI / CD (Fastlane, Xcode Cloud, GitHub Actions)

Why Join?

• Build flagship mobile experiences that power enterprise-scale interactions across the globe.
• Work with elite engineers who care about architecture, clean design, and measurable performance.
• Tackle hard, unsolved technical problems in low-latency streaming, mobile systems, and secure communication.
• 100% remote-first, high-trust culture — autonomy, mastery, and impact matter here.
• Competitive salary and benefits, plus the chance to define the mobile direction for a product used by millions.