Senior Ion Developer

Salary: £50,000 - 80,000 per year

Requirements:

• Strong understanding of Java and Spring Boot.
• Proven experience in developing microservice applications.
• Familiarity with streaming, messaging, and Ion MMI components.
• Understanding of Demon manager and database setup on ION.
• Experience in developing low-latency applications.
• Knowledge of modern build pipelines and tools such as UrbanCode, Git, and Jenkins is advantageous.
• Demonstrated experience in multi-threading and a clear approach to automated testing and exception handling.
• Experience with React or web-based front ends is desirable.
• Knowledge of Markets Front Office technology, particularly interest rate swaps, bonds, and futures, is a plus.
• Candidates must show evidence of the above in their CV to be considered.

Responsibilities:

• Collaborate with product owners and business partners to understand requirements and outline proposed solutions.
• Design, implement, test, and maintain microservices within our technology stack.
• Participate in design reviews and provide critical input to enhance design recommendations.
• Ensure compliance with architectural standards throughout all phases of development.
• Conduct code reviews to ensure alignment with the pre-defined Definition of Done and design specifications.
• Troubleshoot application code-related issues and implement effective solutions.
• Uphold the quality and completeness of our products through rigorous unit testing, integration testing, and behaviour-driven development (BDD) practices.

Technologies:

• AI
• Git
• Support
• Java
• Jenkins
• React
• Spring
• Spring Boot
• Web
• microservices
• REST
• UX UI Design

More:

We are recruiting a Senior Ion Developer on a 12-month contract with the possibility of extension. This is a London hybrid role, requiring two days per week on site, and offers a highly competitive umbrella day rate for suitable candidates. We are Pontoon, an employment consultancy committed to improving everyones chance of being part of the workplace. We value inclusion and use our expertise, energy, and enthusiasm to showcase talent and unique experience. Our hiring process includes background screening checks for all hires before commencement, and we use generative AI tools to support a fair, consistent, and efficient candidate screening experience, with all final decisions made by our hiring team.

last updated 33 week of 2026