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 ResponsibilitiesNative 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 (eg, Recent SIM Swap Detected, Verified Business) provided by our Back End 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 QualificationsEducation & 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 modelling.
Proficiency in consuming RESTful APIs and Real Time data streams (eg, 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.
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.
Advanced Systems & Security Expertise
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 Dependent on experience with a guide between £110k-£140K basic + package.