Software Engineer – Full Stack

Callsign

. Design, build, and maintain scalable Java-based backend services and modern frontend web applications .

Posted 10/6/2026full-timeLondon • United KingdomMid-LevelSeniorWebsite

Core Competencies

Role fit

Core Competencies

Use this summary to align your resume positioning with the role.

Demonstrates expertise in designing and building scalable Java-based backend services and modern frontend applications, with a strong focus on RESTful API development and responsive UI design. Proficient in collaborating within Agile teams to deliver secure and intuitive digital experiences while adhering to engineering best practices.

Highest-signal resume keywords

Java Backend DevelopmentSpring BootRESTful API DesignReact Frontend DevelopmentSQL Query Writing

ATS Keywords

Tailor your resume

Applicant Tracking System Keywords

Tip: use these terms in your resume and cover letter to boost ATS matches.

Hard Skills

JavaSpring BootRESTful APIJavaScriptTypeScriptHTML5CSS3SQLOOP FundamentalsMicroservices Architecture

Soft Skills

Strong CommunicationAnalytical ThinkingCollaboration

Tools & Technologies

DockerKubernetesAWSGCPPrometheusGrafanaWebpackNpmViteFigma

Industry Keywords

AgileContinuous ImprovementSecure Coding PracticesObservabilityWeb Accessibility

Tech Stack

Tools & technologies

AngularAWSCloudCypressDockerDynamoDBGoogle Cloud PlatformGrafanaGRPCJavaJavaScriptJestJUnitKafkaKubernetesLinuxMicroservicesMockitoMySQLNoSQLOraclePostgresPrometheusReactRedisReduxSCSSSpringSpring BootSpringBootSQLTypeScriptVue.jsWebpackYarn

About the role

Key responsibilities & impact

Design, build, and maintain scalable Java-based backend services and modern frontend web applications
Develop robust RESTful APIs and integrate frontend interfaces with backend systems
Build responsive, accessible, and performant user interfaces using modern web frameworks
Write clean, testable, and maintainable full-stack code following engineering best practices
Collaborate with Product Managers, UX/UI Designers, QA, and platform teams to translate user requirements into technical solutions
Participate in peer code reviews, contribute to architectural discussions, and address technical debt
Support deployment pipelines, troubleshoot production issues across frontend and backend layers, and drive continuous improvement
Own features from architectural design through implementation, testing, deployment, and operational monitoring
Work in an Agile, collaborative environment alongside Product, Experience Engineers, and QA to deliver secure, scalable, intuitive digital experiences

Requirements

What you’ll need

3–6 years of commercial full-stack software development experience
Strong backend expertise in Java, Spring Boot, and RESTful API design; gRPC experience is a plus
Hands-on frontend experience with modern JavaScript or TypeScript frameworks, preferably React; commercial experience with Vue.js or Angular is also welcome
Proficiency in JavaScript, HTML5, CSS3/SCSS, and responsive UI design
Working knowledge of frontend build tools and package managers such as Vite, Webpack, npm, or yarn
Solid experience with relational databases such as MySQL, PostgreSQL, or Oracle, and SQL query writing
Strong understanding of OOP fundamentals, SOLID principles, and data structures and algorithms
Familiarity with testing frameworks across the stack, such as JUnit, Mockito, Jest, React Testing Library, or Cypress
Familiarity with Docker, Linux environments, and CI/CD pipelines
Exposure to microservices architecture
Awareness of secure coding practices including OWASP Top 10, XSS, CSRF prevention, and secure authentication/token management
Strong communication, analytical thinking, and collaboration skills
Experience with Java 17 and Spring WebFlux with Project Reactor, or Java 21+ Virtual Threads
Production experience with NoSQL systems such as DynamoDB
Production experience with TypeScript and modern frontend state management such as Redux Toolkit or Zustand
Familiarity with design systems, component libraries, and tools like Storybook or Figma
Production experience with microservices architecture, distributed caching with Redis, and event streaming with Kafka
Familiarity with container orchestration, Kubernetes, Helm, and cloud platforms such as AWS or GCP
Familiarity with observability and monitoring tools such as Prometheus, Grafana, OpenTelemetry, or Elastic Stack
Basic understanding of web accessibility and web performance optimisation

Benefits

Comp & perks

Pension scheme with Scottish Widows
Private medical cover with Vitality
Life assurance (4x base salary)
Personal Learning & Development Budget
Cycle to Work Scheme
Company Family Leave
25 days annual leave plus Callsign Bank Holiday
Employee Volunteering Program