Senior Backend Engineer (Platform & Security)

Senior Backend Engineer (Platform & Security)

We are seeking a deeply technical and security-minded Senior Backend Engineer to join a newly-founded, high-impact AI joint venture. Backed by five of the world's leading telecommunications giants, our mission is to restore trust in global voice communication. We are building a new category of network-native B2C security, moving from reactive, in-call analysis to proactive, pre-call verification that stops fraud before it starts.

This is not a typical Back End role. You will be the Stability & Monetization Owner, the foundational engineer responsible for two of the most critical pillars of our platform: our monetization engine and our Zero Trust security architecture. You will build the systems that protect our users' most sensitive data, including PII and biometric voiceprints, while navigating complex global compliance laws. You will also build the metering and entitlements engine that powers our entire freemium business model.

This position offers a unique opportunity to build a globally-scalable, highly secure, and compliant platform from the ground up. If you believe security and privacy are non-negotiable product features and you are excited by the challenge of building the commercial and trust-based foundation of a new product category, this role is for you.

Key Responsibilities Monetization & Platform Architecture

• Design, build, and own the end-to-end metering and entitlements system that powers our freemium business model, targeting a 30% premium conversion rate.
• Architect and manage our core database solutions (eg, PostgreSQL for user data, Redis for high-speed caching), ensuring high availability, scalability, and security for call logs and user-profiles.
• Develop core, non-feature-specific Back End services such as user account management, settings, and asynchronous task processing via our AI Service Bus (eg, Apache Kafka).

Security & Trust Implementation

• Serve as the primary engineering owner for implementing our application-layer Zero Trust architecture, working hand-in-glove with our DevOps and InfoSec partners.
• Implement robust authentication and authorization services (eg, Role-Based Access Control) for all internal and external APIs, ensuring strict adherence to the Principle of Least Privilege (PoLP).
• Implement industry-leading data security practices for handling highly sensitive PII and biometric data (voiceprints), ensuring end-to-end encryption for all data in transit (mTLS) and at rest (AES-256).

Compliance-as-Code & Observability

• Collaborate with legal and product teams to translate complex global privacy laws (eg, Germany's GDPR, South Korea's PIPA, United Arab Emirates's PDPL) into concrete engineering logic.
• Build and maintain the Policy Engine that enables our platform to be jurisdiction-aware, dynamically managing data handling, consent flows, and feature-gating based on user location.
• Partner with the DevOps Engineer to create comprehensive logging, monitoring, and analytics systems (eg, using Prometheus, Grafana, OpenTelemetry) to provide deep visibility into platform health, security events, and business KPIs.

Required Qualifications Education & Experience

• Bachelor's degree in Computer Science or a related technical field.
• 5+ years of hands-on experience in Back End engineering, building and maintaining high-availability, scalable services in a production environment.

Technical & Platform Skills

• Deep proficiency and hands-on production experience in Go (Golang our stack). Go is the required language for this role as we are standardizing it for our core platform and security services.
• Strong architectural knowledge of database solutions, including relational (eg, PostgreSQL) and caching (eg, Redis) systems.
• Demonstrated experience building services on a major cloud platform (eg, AWS, Azure, GCP).
• Strong understanding of distributed systems, microservices architecture, and API design.

Security & Compliance

• A deep and demonstrable security-first mindset.
• Hands-on experience implementing security best practices at the application layer, including authentication (eg, OAuth 2.0, JWT), authorization (RBAC), and data encryption.
• Experience in securely handling and storing sensitive user data (PII).

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.