{"id":1916851,"url":"https://alion.io/job/callsign-software-engineer-full-stack-2","title":"Software Engineer (Full Stack)","company":{"id":51577,"name":"Callsign","domain":"callsign.com","url":"https://alion.io/company/callsign","size_band":"201-500","is_staffing_agency":false,"employer_type":"direct","is_intermediary":false,"listed_via":null,"ats_vendor":"Workable","truth_index":null},"role":"Backend","role_family":"Backend","seniority":null,"employment_type":"full_time","work_mode":"on_site","remote_scope":null,"remote_scope_basis":null,"remote_working_hours":null,"hiring_geo_confidence":"structured","locations":["London, United Kingdom"],"countries":["GB"],"hiring_countries":[],"hiring_countries_total":0,"salary":null,"salary_estimate":{"min_usd":73000,"max_usd":181000,"period":"year","method":"role_country_seniority_unknown","sample_n":351},"experience_years_min":null,"visa_sponsorship":false,"relocation_package":false,"has_equity":false,"technologies":[{"name":"Agile","optional":false},{"name":"gRPC","optional":false},{"name":"Spring Boot","optional":false},{"name":"Angular","optional":true},{"name":"Apache Kafka","optional":true},{"name":"AWS","optional":true},{"name":"CI/CD","optional":true},{"name":"Cypress","optional":true},{"name":"Docker","optional":true},{"name":"DynamoDB","optional":true},{"name":"Figma","optional":true},{"name":"GCP","optional":true},{"name":"Grafana","optional":true},{"name":"Helm","optional":true},{"name":"Java","optional":true},{"name":"JavaScript","optional":true},{"name":"Jest","optional":true},{"name":"JUnit","optional":true},{"name":"Kotlin","optional":true},{"name":"Kubernetes","optional":true},{"name":"Linux","optional":true},{"name":"Mockito","optional":true},{"name":"MySQL","optional":true},{"name":"npm","optional":true},{"name":"OpenTelemetry","optional":true},{"name":"OWASP Top 10","optional":true},{"name":"PostgreSQL","optional":true},{"name":"Prometheus","optional":true},{"name":"React.js","optional":true},{"name":"Redis","optional":true},{"name":"Redux","optional":true},{"name":"Redux Toolkit","optional":true},{"name":"Sass","optional":true},{"name":"SQL","optional":true},{"name":"State Management","optional":true},{"name":"Storybook","optional":true},{"name":"TypeScript","optional":true},{"name":"Vite","optional":true},{"name":"Vue.js","optional":true},{"name":"Webpack","optional":true},{"name":"Zustand","optional":true}],"status":"live","first_seen_at":"2026-10-05T16:36:35Z","employer_posted_date":"2026-10-05","last_verified_at":"2026-10-08T00:09:45Z","board_verified":true,"closed_at":null,"days_open":2,"trust":{"level":"ok","repost_count":null,"flags":[],"days_open":2},"description":"As a Full Stack Software Engineer at Callsign, you will design, build, and maintain end-to-end features spanning our high-throughput Java backend services and modern web interfaces. You’ll work in an Agile, collaborative environment alongside Product, Experience Engineers and QA to deliver secure, scalable, and intuitive digital experiences. You will take ownership of features from architectural design through implementation, testing, deployment, and operational monitoring.\nWhat you'll do\nDesign, build, and maintain scalable Java-based backend services and modern frontend web applications.\nDevelop robust RESTful APIs and integrate frontend interfaces seamlessly with backend systems.\nBuild responsive, accessible, and performant user interfaces using modern web frameworks.\nWrite clean, testable, and maintainable code across the full stack following engineering best practices.\nCollaborate closely with Product Managers, UX/UI Designers, QA, and platform teams to translate user requirements into technical solutions.\nParticipate in peer code reviews, contribute to architectural discussions, and proactively address technical debt.\nSupport deployment pipelines, troubleshoot production issues across frontend and backend layers, and drive continuous improvement.\nRequirements\n3-6 years of commercial full-stack software development experience.\nStrong backend expertise in Java, Spring Boot, and RESTful API design; gRPC experience is a plus.\nHands-on frontend experience with modern JavaScript or TypeScript frameworks, preferably React. Commercial experience with Vue.js or Angular is also welcome.\nProficiency in JavaScript, HTML5, CSS3/SCSS, and responsive UI design.\nWorking knowledge of frontend build tools and package managers such as Vite, Webpack, npm, or yarn.\nSolid experience with relational databases such as MySQL, PostgreSQL, or Oracle, and SQL query writing.\nStrong understanding of OOP fundamentals, SOLID principles, and data structures and algorithms.\nFamiliarity with testing frameworks across the stack, such as JUnit, Mockito, Jest, React Testing Library, or Cypress.\nFamiliarity with Docker, Linux environments, and CI/CD pipelines.\nExposure to microservices architecture.\nAwareness of secure coding practices including OWASP Top 10, XSS, CSRF prevention, and secure authentication/token management.\nStrong communication, analytical thinking, and collaboration skills.\nGood to have :\nExperience with Java 17 and Spring WebFlux with Project Reactor, or Java 21+ Virtual Threads.\nProduction experience with NoSQL systems such as DynamoDB.\nProduction experience with TypeScript and modern frontend state management such as Redux Toolkit or Zustand.\nFamiliarity with design systems, component libraries, and tools like Storybook or Figma.\nProduction experience with microservices architecture, distributed caching with Redis, and event streaming with Kafka.\nFamiliarity with container orchestration, Kubernetes, Helm, and cloud platforms such as AWS or GCP.\nFamiliarity with observability and monitoring tools such as Prometheus, Grafana, OpenTelemetry, or Elastic Stack.\nBasic understanding of web accessibility and web performance optimisation\nBenefits\nPension scheme with Scottish Widows\nPrivate medical cover with Vitality\nLife assurance (4x base salary)\nPersonal Learning & Development Budget\nCycle to Work Scheme\nCompany Family Leave\n25 days annual leave plus Callsign Bank Holiday\nEmployee Volunteering 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