Experience Engineer (FTC)

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.

The candidate will already need to hold the right to work in the UK.

What you’ll do:

Product & UX:

• 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

Frontend craft:

• Implement non-trivial components and async data flows
• Diagnose and fix performance and accessib