Senior 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 to 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 a product surface (portal domain, demo platform, SDK) and holds its product decision right
• Within the direction Product sets, decide what ships and how it works.
• Translate a brief into an MVP and phases, define the success measures for what ships, and reshape or kill work that will not move them.
• Your surface carries a live measurement baseline (adoption, task success, performance) that decisions cite and post-release reviews are judged against; a decision that would change the direction goes to the PM, not around them.
• Propose what to build next from your own product conviction, built from user and client contact, rather than merely executing requests
• Be trusted to ship client-facing work without design review.

Frontend craft:

• Set the technical standard for th