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# Experience Engineer (FTC)

- **Company:** Callsign
- **Location:** London, UK
- **Salary:** £60,390.0
- **Contract:** Temporary contract
- **Skills:** Java (Programming Language), JavaScript (Programming Language), Application Programming Interfaces (APIs), Artificial Intelligence, Software Quality, Data Visualization, Software Debugging, Node.Js, Data Streaming, Toolchain, TypeScript, ReactJS, Backend, Gitlab-ci, Material UI, Front End Software Development, Terraform, Api Management
- **Published:** October 6, 2026
- **Apply:** https://www.adzuna.co.uk/jobs/details/5912667591

## About the Role

A must:

 * 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.

Would be great:

 * 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.

Nice to have:

 * Java in production; design systems or component library work; SDK or library engineering; data visualisation
 * Experience in regulated industries (fintech, identity, payments).

## Description

* 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 accessibility issues rather than merely detecting them
 * Handle secrets/config surfaces safely

Full-stack

 * 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

Quality

 * 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

Platform:

 * 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.