UI Engineer in London

• This listing's locations Hybrid - London
• Employment Full time
• Workplace Hybrid
• Department: Product Development
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Valarian Technologies is a dual-use technology company building critical tools to safeguard the future in an era of evolving global security challenges.

We're rethinking security beyond traditional military domains, addressing asymmetric threats that impact our technological advantage, economic strength, and democratic institutions.

We build Acra - the platform foundation for everything we do as a dual-use technology company.

The platform’s name, rooted in the Greek word for citadel (or, fortress), reflects the design and purpose of our infrastructure-agnostic secure enclaves: protecting critical data.

Some of the government and commercial workflows include: increased operational resiliency for mission-critical systems and functions; enabling organisations to more quickly and widely adopt emerging technologies while ensuring the integrity of their intellectual property; information flow during disaster response scenarios, and zero-trust / least-privilege environments for M&A, attorney-client privileged communications, etc.

And we’ve only scratched the surface.

At our core, we're driven by a shared mission and a belief in making a tangible impact on our world.

Whether you join our London HQ or the wider global organisation, you’ll be a part of collaborative, high-performing teams, creating cutting-edge software, platforms, and infrastructure.

The Role

You will design, build, and maintain mission-critical user interfaces for Acra, our secure-enclave platform protecting sensitive government and commercial workflows.

You will bridge web and native mobile environments-working primarily with React/Type Script for complex web dashboards and administrative consoles, alongside native mobile platforms using Swift (i OS) or Kotlin/Java (Android) to deliver responsive, zero-trust client applications for operators in the field.

You will own front-end systems end-to-end: from UI architecture, state management, and API integration down to client-side performance, local encryption, accessible design systems, and cross-platform reliability.

You will help shape the frontend delivery foundations, including modular component architectures, CI/CD testing pipelines, web and mobile packaging, offline-first sync strategies, and secure local storage.

ACRA’s architecture separates the control plane, platform enforcement layer, and isolated execution environments.

This role requires someone who can build fluid, intuitive interfaces while reasoning clearly about client-side trust boundaries, data leakage prevention, authentication flows, and operational security.

This is not a role for someone who only wants to take tickets.

We are looking for someone who understands the product vision, advocates for user safety and accessibility, challenges assumptions, and translates ambiguous workflows into crisp, resilient user experiences.

What you’ll do

• Architect and build high-performance, accessible, and secure user interfaces across React/Type Script and native mobile clients (Swift/i OS or Android).
• Own client applications from technical design and UI component implementation through to testing, deployment, observability, and production operations.
• Integrate complex RESTful and Web Socket/event-driven APIs, handling real-time data streaming, optimistic updates, and offline/low-bandwidth resilience.
• Build and maintain a scalable design system that ensures aesthetic consistency, compliance, and strict usability across both desktop and mobile form factors.
• Address client-side security concerns: secure token handling, biometric authentication, encrypted local cache, certificate pinning, and zero-trust session management.
• Partner closely with product managers, UX designers, backend engineers, and security specialists to turn mission-critical requirements into clear interfaces.
• Establish frontend and mobile testing best practices (unit, component, and end-to-end integration tests).
• Raise engineering standards through design reviews, accessible code practices, and thorough documentation.
• Operate independently in a fast-paced environment with strong ownership and product thinking.

What we are looking for

• Strong professional engineering experience building production-grade web applications with modern React and Type Script.
• Solid hands-on native mobile development experience with Swift (i OS) or Kotlin/Android (or proven experience bridging cross-platform architectures with native modules).
• Deep understanding of modern UI architecture, state management paradigms, and responsive design systems.
• Experience consuming, designing, and optimizing APIs (REST, Web Sockets, or Graph QL) for client performance and intermittent connectivity.
• Familiarity with client-side security fundamentals (content security policies, token management, secure device storage, threat modeling at the client layer).
• Strong track record of end-to-end feature ownership from Figma mocks to app deployment and post-release monitoring.
• Disciplined approach to automated testing (Jest, React Testing Library, XCTest/Espresso, Playwright/Cypress).
• Product-minded engineering judgment: you care deeply about how users navigate critical workflows, not just what ticket needs to be resolved.
• A self-driven, ownership-oriented mindset comfortable with technical ambiguity and fast feedback loops.

Nice to have

• Experience building interfaces for secure or regulated environments (defence, government, cybersecurity, fintech, or critical infrastructure).
• Familiarity with Web Assembly (Wasm), client-side cryptography, or zero-knowledge protocols.
• Hands-on experience with native mobile app deployment, MDM (Mobile Device Management) enterprise distribution, or App Store / Play Store governance.
• Experience with real-time collaborative interfaces, mapping/GIS visualisations, or tactical telemetry dashboards.
• Familiarity with container-based frontend workflows, mobile CI/CD pipelines (Fastlane, Git Hub Actions), and frontend observability tools (Sentry, Datadog RUM).
• Systems where auditability, accessibility compliance (WCAG 2.1+), and operational evidence are first-class requirements.

Our benefits are designed to ensure our employees feel taken care of and are proud to be a part of the Valarian team.

We are committed to consistently enhancing our benefit package, taking into account the overall well-being and needs of our teammates.

• Here are the key benefits accessible to all employees at
• Valarian

Technologies

• Equity - because you have the right to own what you’re building
• A competitive salary - because we value your unique skills
• Employer pension contributions - because you deserve a secure future
• Private health insurance - because your health is important to us
• Hybrid work setup - because everyone has different needs
• Rewarding company retreats and meetups that respect your work/life balance - because we love getting to know each other!
• Life at Valarian

Our culture is built on inclusivity, compassion and flexibility - we want everyone to be empowered to achieve their goals at Valarian.

The work we do is vital, but so are the connections that make it happen.

We thrive on the shared energy, spontaneous conversations, and mutual trust built when we spend time together.

We operate on a hybrid model, gathering in our London office 3 days a week to support one another and collaborate.