Job Description

Job Title: Senior Java Developer - Telecommunications

Location: Guildford

Job Type: Full-Time, Permanent

About Nebula

Nebula is a leading SaaS provider of advanced communications software, purpose-built to empower partners and customers with resilient, scalable solutions. With over a decade of expertise, our proprietary UCaaS (Unified Communications as a Service) technology supports more than 500 channel partners and drives seamless communication for 200,000 daily active users via our award-winning 'CallSwitch One' and 'Yay.com' brands.

With the support of a leading growth-stage investor, we are at an exciting stage on our ambitious journey to be the platform of choice in business communication software. From our offices in Guildford and London, our 70-strong UK team delivers a platform that fuels growth, enhances customer experience, and meets the demands of modern digital infrastructure.

About the Role:

We are seeking a skilled Backend Java Developer with at least 5-7 years of experience and proven expertise in the Telecommunications sector to design and implement high-availability, mission-critical backend systems.

Key responsibilities include:

Design, develop, and maintain backend services and microservices using Java, ensuring high availability and reliability for telecom applications. Collaborate with cross-functional teams to deliver scalable solutions for telecom network monitoring, management, and testing. Integrate and optimize databases and APIs for efficient data flow and system interaction. Implement security, redundancy, and performance tuning tailored for telecom operations. Troubleshoot and resolve technical challenges in distributed systems and client environments. Contribute to Agile development, participate in code reviews, and maintain best practices across the software lifecycle.
You'll need to have the following to ensure we can consider your application:

Minimum 4 years' hands-on experience in backend Java development, preferably in telecommunications or similar mission-critical domains. Strong expertise in designing and building RESTful APIs, and microservice architectures. Extensive experience developing distributed systems, with understanding of OOP, design patterns, and networking fundamentals. Experience with cloud environments (AWS, GCP, etc.), containers (Docker, Kubernetes), and CI/CD pipelines. Proven history of optimizing applications for performance, memory, and scalability--especially under telecom workloads. Familiarity with SQL/NoSQL databases, including deployment, consistency models, and integration. Knowledge of messaging technologies (Google Pub/Sub, Kafka, RabbitMQ, etc.) relevant to telecom event streaming. Strong interpersonal, analytical, and communication skills; able to break down complex requirements and collaborate effectively.
Some 'nice to have' experience that would really help you excel:

Experience with telecom-specific protocols (SMPP, SIP, etc.), network APIs, or OSS/BSS integrations. Exposure to event-driven systems, CQRS, and high-redundancy architectures. Background in security scanning, testing (unit/integration), and version control (Git). A keen interest or experience in Kotlin. Bachelor's degree in Computer Science, Engineering, or related field. Experience in an Agile/Scrum environment.
What we look for in everyone who works here:

A clear communicator who collaborates well with both technical and non-technical stakeholders

A proactive problem-solver with a self-starting attitude

Curious and always looking to improve your skills and knowledge

Excited about contributing to a growing team and product

What we offer

At Nebula, we prioritise your professional growth and wellbeing. Our benefits include health cash plans, enhanced leave for new parents, ongoing training and career development, fun team events, and chances to connect with industry groups like Women in Telecoms. Our "Team First" value ensures a supportive and empowering work environment where you can excel.

We are proud to serve a diverse range of clients and believe in building a team that reflects that diversity. We're committed to ensuring everyone is treated fairly and respectfully throughout the hiring process and their employment with us. This means creating an inclusive environment for all, regardless of age, disability, gender, marital status, parental status, race, religion/belief, or sexual orientation.

Work Authorisation

You must have the right to work in the United Kingdom.

Job Type: Full-time

Pay: 55,000.00-65,000.00 per year

Work Location: Hybrid remote in Guildford GU1 4UG