Experience Engineer, Callsign
Experience Team
More information about location
2+ days a week in office
Fraud prevention, authentication & intelligence
Be an early applicant
Fraud prevention, authentication & intelligence
201-500 employees
Be an early applicant
More information about location
2+ days a week in office
201-500 employees
Company mission
To seamlessly power the identification of every web, mobile and physical interaction.
Role
Who you are
- Solid JavaScript/TypeScript and React
- Comfort somewhere beyond the frontend: an API, a service, or infrastructure
- System design and architecture, designing features that span frontend, service and configuration
- Evidence of AI-native working with stated verification
- A testing instinct: you can design a test approach and defend it
- Java in production; design systems or component library work; SDK or library engineering; data visualisation
Desirable
- Product judgement demonstrable from your history: UX decisions made and defended without a design spec
- Ownership of a surface or programme through its worst weeks, at any scale
- Experience in regulated industries (fintech, identity, payments)
What the job involves
- The Experience team owns the human-facing side of Callsign: the client portal, our demo and client management platform (one platform for the whole client journey, from first demo through proof of concept, onboarding, integration, analysis and ongoing management), the data-product UIs, and the design system and engineering standards behind all of it
- This position is offered as a 12 month fixed-term contract with the successful candidate ideally joining in 2026
- Own features end-to-end, from ambiguous requirements to shipped experience: fills design gaps with defensible decisions and delivers a coherent flow rather than a set of components
- Contribute actively in refinement: challenge requirements with evidence, propose simpler alternatives, and bring product ideas of your own
- Know the outcome each feature serves, instruments what they ship so that outcome is measurable, and checks whether it landed (usage, feedback, demo performance) rather than stopping at merge
- Understand the domain the product lives in (fraud, identity, authentication, and the client's operational world) well enough so that gap-filling decisions reflect
- Implement non-trivial components and async data flows
- Diagnose and fix performance and accessibility issues rather than merely detecting them
- Handle secrets/config surfaces safely
- Ship features that span frontend, backend service and configuration
- Debug across the boundary to root cause
- Significant changes start as a written design others can review, rather than as code
- Design the test approach for your features (what gets unit, component and e2e coverage, and why)
- Keep regression suites healthy in your area; e2e failures you own get fixed rather than retried
- Land toolchain and pipeline improvements (build config, CI automation, test infra, dependency upgrades) beyond your immediate feature work
- Ship across the stack: TypeScript/React frontends, Node services (with some Java in the portal estate), API contracts, GitLab CI/CD, and deployment via Helm, GitOps and Terraform
- Treat the frontend craft triad - accessibility, performance, security - as engineering, with expectations that rise as you grow
- Build with AI as a core part of your workflow, with the verification discipline a regulated product demands
- Learn the domain deliberately: fraud, identity, authentication, and our clients' operational world, because product decisions made without it are guesses
- Write meaningful tests for everything you ship
Salary benchmarks
Our take
Callsign uses deep learning technology to analyse a variety of real time signals such as the GPS location, force of touch and screen co-ordinates to identify potentially suspicious usage of a device. Collaborating with Lloyds bank, the company's technology helps to mitigate unauthorised access while providing a seamless user experience.
Callsign is not the only company in this area, and faces competition from other firms such as AimBrain, Behaviosec, and BioCatch. To stand out, its AI system takes into account a combination of different factors to improve its accuracy and reliability. It has also built security in, with all data encrypted on the device itself before being sent to the server.
Steph
Company Specialist at Welcome to the Jungle
Insights
18% employee growth in 12 months
Company
Funding (last 2 of 4 rounds)
Jun 2023
$73.9m
LATE VC
Jul 2017
$35m
SERIES A
Total funding: $112.7m
Company benefits
- Health & wellbeing: From health insurance to discounted gym memberships to childcare vouchers, we constantly invest in the health and wellbeing of our teams
- Learning: Collective growth is one of our core values. Learning opportunities and learning support are core to the Callsign experience
- Family benefit: As well as personal health and wellbeing benefits, we also offer various other discounts like home utilities and childcare vouchers
- Holidays: In addition to 25 days annual leave (on top of bank holidays), you'll also get an additional Callsign bank holiday in June
- Flexible working hours: We've all got different priorities and pressures in our lives. Our flexible working policy will help lighten the load
- Multiple locations: We know that different people work best in different environments – that's why we offer opportunities for flexibility in your working environment
Company HQ
City of London, London, UK
Leadership
Zia Hayat
(CEO)Previously held positions at Accenture, BAE Systems and Lloyds, where he designed and delivered critical military and financial information systems.
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