Java Senior Developer - Core Services

Cognizant; Greater London; Hybrid; GBP 70,000 - 110,000; Full time

Job summary

Cognizant Technology Solutions Corporation in London is seeking a Senior Developer, Core Services to build scalable backend systems for live and streaming services, using Java and Spring and to shape architecture and reliability. The role requires ownership of performance and security and close collaboration with architecture and product teams.

You will work on RESTful APIs, event-driven patterns with Kafka, and cloud-native stacks on AWS with Docker/Kubernetes, Redis, and Cassandra.Key

Qualifications

• Strong hands-on experience in Java and Spring Framework development.
• Proven experience building web applications and RESTful APIs.
• Solid understanding of event-driven architectures, including Kafka, asynchronous messaging, and distributed systems.
• Experience working with AWS and AWS-native cloud services.
• Strong knowledge of database and persistence technologies such as Cassandra/AWS Keyspaces, Redis, and PostgreSQL/DSQL.
• Experience with containerization and orchestration technologies, including Docker and Kubernetes.
• Hands-on experience with CI/CD pipelines, particularly using GitHub Actions and modern software delivery practices.
• Experience with automated testing frameworks and a good understanding of NF requirements such as performance, scalability, security, and reliability.
• Proficiency with Unix/Linux environments and Bash scripting.

Responsibilities

• Develop and maintain components using Java and Spring, covering new features, fixes, enhancements, and existing functionality.
• Build well-tested, robust and reliable code, including handling edge cases and usability considerations
• Identify production/code issues and use appropriate debugging techniques and tools for resolution.
• Support non-functional testing, including performance, resiliency, and security considerations.
• Maintain and support AWS infrastructure, Kubernetes deployments, AWS Keyspaces, Redis and Kafka.
• Review peer code and ensure adherence to coding standards and engineering best practices.
• Propose technical solutions and make design decisions for complex, scalable systems.
• Collaborate with developers, architects, and analysts to understand requirements and deliver solutions.
• Participate in stand-ups and other Agile/team ceremonies and contribute to continuous improvement.

Skills

Java

Spring

REST APIs

Kafka

AWS

Docker

Kubernetes

CI/CD

Unix/Linux

Bash

Event-driven

Debugging

Tools

GitHub Actions

AWS

Docker

Job description

Location: London, UK
Employment Type: Full-time
Work Model: Hybrid

About the Role

The Senior Developer, Core Services role is focused on building and supporting highly scalable backend systems for live and Video on Demand streaming services. The developer will work primarily with Java and Spring, developing end-user applications and scalable APIs while contributing to technical direction, architecture/design decisions, production support, system reliability, and continuous improvement.

The role also requires ownership of functional and non-functional quality, particularly security, resiliency, and performance, along with strong collaboration across development, architecture, and other teams.

In this role, you will:

• Develop and maintain components using Java and Spring, covering new features, fixes, enhancements, and existing functionality.
• Build well-tested, robust and reliable code, including handling edge cases and usability considerations
• Identify production/code issues and use appropriate debugging techniques and tools for resolution.
• Support non-functional testing, including performance, resiliency, and security considerations.
• Maintain and support AWS infrastructure, Kubernetes deployments, AWS Keyspaces, Redis and Kafka.
• Review peer code and ensure adherence to coding standards and engineering best practices.
• Propose technical solutions and make design decisions for complex, scalable systems.
• Collaborate with developers, architects, and analysts to understand requirements and deliver solutions.
• Participate in stand-ups and other Agile/team ceremonies and contribute to continuous improvement.

What You Need to Have to Be Considered

The ideal candidate will have strong experience in backend software engineering and cloud-native application development, with expertise in the following areas:

• Strong hands-on experience in Java and Spring Framework development.
• Proven experience building web applications and RESTful APIs.
• Solid understanding of event-driven architectures, including Kafka, asynchronous messaging, and distributed systems.
• Experience working with AWS and AWS-native cloud services.
• Strong knowledge of database and persistence technologies such as Cassandra/AWS Keyspaces, Redis, and PostgreSQL/DSQL.
• Experience with containerization and orchestration technologies, including Docker and Kubernetes.
• Hands-on experience with CI/CD pipelines, particularly using GitHub Actions and modern software delivery practices.
• Experience with automated testing frameworks and a good understanding of non-functional requirements such as performance, scalability, security, and reliability.
• Proficiency with Unix/Linux environments and Bash scripting.
• Experience designing and implementing scalable, resilient software solutions.
• Strong engineering fundamentals, including debugging, code reviews, system reliability, and software development best practices.

Additional eligibility requirements:

Candidates must currently reside in the UK.

Candidates must be available to start within 4 weeks of receiving an offer.

These Will Help You Stand Out

• Observability: Datadog, Prometheus and Grafana.
• AI/ML technologies: SageMaker, Azure and Gemini LLMs.
• Confidence with AI-assisted / agentic software development.
• Broader understanding of relevant technologies and modern software architecture.
• Strong cross-team collaboration and communication skills.
• Self-driven attitude with an interest in continuously learning new technologies, frameworks and engineering practices.
• Creative thinking, analytical ability and attention to detail.