Senior Android Engineer (Native Integration & Security)
We are seeking an exceptional Senior Android Engineer to join a newly-founded joint venture backed by five of the world's leading telecommunications companies. Our mission is to restore trust in voice communication by building a network-native intelligence layer to combat the global epidemic of voice fraud and AI-driven scams.
In this role, you will be the owner of our most critical, user-facing feature: the Telco-Verified Security Shield. You will be responsible for the “magic moment” of our product, delivering an instant, network-verified trust indicator to a user's device in the moments before they answer the call. This is not a standard mobile app role; it is a deep, real-time systems challenge that requires you to architect and implement a high-performance, secure, and reliable solution that integrates directly with the Android operating system's native call-handling services.
Your primary objective is to own the client-side implementation of our sub-500ms “Time-to-Trust” (TtT) metric. You will be the driving force behind the “trust” in our product, working at the intersection of native mobile engineering, real-time data processing, and client-side security. This position offers a unique opportunity to build a category-defining security product from the ground up, leveraging proprietary, network-level data that no pure-OTT competitor can access.
Key Responsibilities
Native OS Integration & Performance
* Architect, build, and own the entire native call interception flow using Android's CallScreeningService to intercept and analyze calls as they ring.
* Design and engineer the high-performance “Trust Indicator” overlay, obsessing over every millisecond of client-side processing to ensure we meet our strict sub-500ms Time-to-Trust (TtT) metric.
* Implement the client-side logic to consume and display “Explainable AI” reasoning (e.g., “Recent SIM Swap Detected,” “Verified Business”) provided by our backend services.
* Build a robust, efficient, and scalable client-side API integration layer to consume real-time security signals (like our proprietary Scam_Score) from the AI Core.
Security & Quality
* Implement and champion our mandatory “Zero Trust” security architecture at the client level, ensuring all network data and user PII are handled with the highest level of security.
* Define and enforce best practices for performance, code quality, and testing for the entire Android security stack.
* Work closely with the QA Engineer to build test harnesses and instrumentation to rigorously validate the sub-500ms latency target and ensure a false-positive rate of less than 1%.
Cross-functional Collaboration
* Partner with the Senior Backend Engineer (Application & AI Orchestration) to define the API contracts and real-time data flow needed to power the Security Shield.
* Collaborate with the UX/UI Designer to iterate on a seamless, intuitive, and trustworthy user experience for the trust indicator and its explanations.
* As a foundational engineering hire, you will help define our Android engineering culture, mentor future hires, and set the standard for technical excellence.
Required Qualifications
Education & Experience
* Bachelor's degree in Computer Science, Engineering, or a related field.
* 5+ years of hands-on experience in native Android development, with a portfolio of high-performance, public-facing applications.
Required Technical & Android Skills
* Expert-level, production-grade experience with native Android development (Kotlin required).
* Demonstrated, deep expertise with Android's native call-handling APIs, specifically the CallScreeningService framework. This is a critical, non-negotiable skill for this role.
* Proven experience building high-performance, real-time user interfaces that are deeply integrated with the Android OS.
* Strong understanding of mobile security principles and best practices, including secure data storage, network communication (mTLS), and threat modeling.
* Proficiency in consuming RESTful APIs and real-time data streams (e.g., WebSockets) in a mobile environment.
* Strong understanding of Android performance profiling tools and techniques to debug and optimize for latency.
* Experience with multi-threaded and asynchronous programming on Android.
Preferred Qualification
Advanced Education & Industry Experience
* Master's degree in Computer Science or a related field.
* Previous experience in the telecommunications, cybersecurity, or anti-fraud/anti-spam industries.
* Experience building applications for a global audience with localization and compliance requirements.
Advanced Systems & Security Expertise
* Experience with the Android NDK (C++) for performance-critical operations.
* Familiarity with real-time audio processing on Android.
* Deep knowledge of mobile network protocols and security.
* Experience building or integrating SDKs.
This is a permanent position with hybrid working of two days a week in the central London office and the rest WFH. The salary is very much dependant on experience with a guide between £110k-£140K basic + package.