Senior Developer

Cerillion Americas; Greater London; On-site; GBP 90,000 - 130,000; Full time

Benefits offered by this job

23 days leave

Healthcare cover

Training programs

Employee Assistance

Travel opportunities

Covent Garden office

Job summary

Cerillion in London is seeking a Senior Developer to join our Software Engineering team. You will design, develop, and deliver enhancements to Cerillion’s core BSS/OSS products, mentor juniors, and collaborate with architects and cross-functional teams to ensure robust, scalable systems.

The role focuses on Java-based technologies, Spring Boot, RESTful APIs, microservices, and containerisation with Kubernetes/OpenShift, with responsibilities across Agile delivery and code quality.

Qualifications

• Degree in Computer Science or related field.
• Extensive Java development experience.
• Experience with high-transaction, large-scale telecoms/enterprise systems preferred.
• Strong knowledge of SDLC and Agile methodologies.
• Hands-on leadership or mentoring experience.

Responsibilities

• Understand customer requirements and R&D needs.
• Analyse existing system functionality and identify gaps.
• Participate in design discussions with architects and analysts.
• Design and develop customisations to Cerillion’s core BSS products, including CRM, Mediation, Billing, Provisioning, Product Catalogue, and Self Service.
• Develop new features for the product suite.
• Perform code reviews and unit testing to standards.
• Work in Agile environments, participate in sprint planning.
• Support bug fixing, performance optimisation, and integration testing.
• Provide build and release instructions to DevOps and QA.
• Mentor developers and contribute to technical guidelines.

Skills

Java

Spring Boot

J2EE

RESTful APIs

Microservices

Kubernetes

OpenShift

SQL

Git

Maven

Jenkins

SDLC & Agile

Education

Bachelor's degree in Computer Science or Software Engineering

Tools

Maven

Jenkins

Git

Job description

Cerillion is a leading provider of billing, charging and customer management systems with more than 25 years’ experience delivering its solutions to the telecoms sector.

We are looking for a Senior Developer to join our Software Engineering team in London. This
role is ideal for a hands-on technologist who enjoys tackling complex business challenges and
delivering high-quality software solutions. The successful candidate will be responsible for
technical design, development, and delivery of enhancements to Cerillion’s core BSS/OSS
products.

You will work closely with project managers, architects, and cross-functional development
teams to ensure the delivery of robust, scalable, and maintainable systems. As part of this role,
you will also mentor junior developers and contribute to code quality and process improvement
initiatives.

Key responsibilities include:

Understand customer business and R&D requirements.

Analyse existing system functionality and design gaps.

Participate in requirements and design discussions with architects and analysts.

Design and develop customisations to Cerillion’s core BSS products, including CRM,
Mediation, Charging and Rating, Billing, Bill Printing, Credit Control, Provisioning, Product
Catalogue, and Self Service.

Develop new R&D; features and modules for inclusion in the product suite.

Perform code reviews, unit testing, and ensure compliance with development standards.

Work collaboratively in Agile environments and contribute to sprint planning and estimations.

Support bug fixing, performance optimisation, and integration testing.

Provide build and release instructions to DevOps and QA teams.

Support build and deployment processes, ensuring smooth release cycles and quality
assurance.

Report project/task status, risks, and issues to the Software Engineering Manager.

Mentor developers and assist in technical troubleshooting and solutioning.

Contribute to technical design documentation and best practice guidelines.

What we are looking for in our next Senior Developer:

Educated to degree level (or equivalent) in Computer Science, Software Engineering, or a
related discipline.

Extensive experience in software design and development using Java-based
technologies.

Experience in technical leadership or senior developer roles.

Experience working on high-transaction, large-scale systems in telecoms, billing, or similar
enterprise domains preferred.

Strong expertise in Java, Spring Boot, and J2EE.

Hands-on experience with RESTful APIs, Microservices, and Containerisation
(Kubernetes/OpenShift).

Solid understanding of RDBMS, SQL, and PL/SQL.

Familiarity with application servers such as JBoss or Oracle 10gAS.

Proficiency in Git-based source control, debugging, and build tools (e.g., Maven, Jenkins).

Knowledge of software development lifecycle (SDLC) and Agile methodologies.

What we provide:

• 23 days annual leave (+ bank holidays), increasing to 28 days after 5 years’ service.
• Vitality healthcare cover.
• Opportunities for internal and external training.
• Employee Assistance Program.
• Opportunities for travel.
• An office in the heart of Covent Garden, providing an excellent base for our team events and social functions.