Software Developer (Back End) - COSMIC

Saffron Walden, United Kingdom

2026-05-03 (Europe/London)

Do you want to help us improve human health and understand life on Earth? Make your mark by shaping the future to enable or deliver life-changing science to solve some of humanity’s greatest challenges.

We are seeking to recruit a passionate Software Developer (Backend) to join our team in developing the best of modern websites and supporting our infrastructure. You will support the world’s key cancer genomics resource, COSMIC (Catalogue of Somatic Mutations of Cancer).

About the Role:
The role focuses on developing reliable, maintainable software using Python-based technologies and modern web frameworks, while supporting deployment, testing, security, monitoring, and ongoing system maintenance. The position also contributes to the design of cloud-ready architectures that ensure COSMIC platforms remain secure, scalable, and resilient, supporting both existing services and the development of new products.

About You:

You must be a skilled and passionate Software Developer (Backend). You will care about writing clean, high quality, readable and maintainable code to support our growing suite of products.

You must be a good communicator and be able to understand the goals and aims of the collaborative COSMIC team and its customers of researchers, scientists, and clinicians, globally.

You will hold a transformational role within COSMIC that will collaborate with the Software Development Leads (web and data), Product Management.

You will help to co-design a completely new suite of bespoke enterprise-level systems to support COSMICs future innovation of products to promote commercial success. Additionally, you will be responsible for maintaining the existing legacy systems. You will co-design and implement high quality, readable and clean APIs and web services using Python, Django. Furthermore, you will assume responsibility for deployment, testing, security, monitoring, and maintenance of COSMICs products.

You will have good technical experience with either GCP or AWS and Docker. You will understand the importance of automation, CICD pipelines and infrastructure as code.

You will have technical experience on Web frameworks - Django, Django-Rest-Framework, FastAPI and/or NodeJS.

Create and deliver designs for cloud-ready and cloud-agnostic, sustainable, enterprise-level business system architectures. This will include designing the underlying framework that facilitates:

• Globally resilient, portable, scalable, flexible, and secure multi-site website presence
• User authentication tools that accommodate both commercial purchases and a system of validating users for free access accounts
• Continued support for both novel and existing products as well as dependent infrastructure
• New Product Development life cycle and Agile delivery
• Interact with a multi-talented team working on an enterprise grade website that has a large user base and experiences a high volume of traffic.

This role has great scope for expanding your skills, knowledge, and interests as a Senior web developer. You will join a multidisciplinary, committed, and supportive team with the opportunity to work on innovative products that make a real difference to patients around the world.

Essential Technical Skills:

• Expertise in Python with familiarity of JavaScript
• Experience in web frameworks - Django, Django-Rest-Framework, FastAPI and/or NodeJS
• Experience in writing unit tests, integration tests and applying TDD
• Understanding clean code principles and thoughtful use of design patterns
• Experience using containers (Docker), working in a Cloud environment
• Knowledge of writing and consuming RESTful APIs
• Knowledge of building web services that depend on complex Database relationships

Essential Competencies and Behaviours:

• A demonstrable, enthusiastic, can-do, learn, proactive attitude
• Enthusiasm, commitment and attention to detail
• Ability to prioritise activities and manage the own workload independently
• Ability to explain technical issues effectively and understandably to non-technical users
• Ability to work collaboratively with a range of stakeholders at all levels
• Ability to understand scientific and technical challenges
• Excellent, broad-based and self-reliant problem-solving skills
• Shows curiosity and a willingness to learn new technologies, tools, and ways of working
• Adjusts to changing requirements, priorities, or technical approaches
• Welcomes feedback from peers and seniors
• Collaborates effectively with team members and contributes to shared goals

About Us:

COSMIC is the key information source in global human cancer research and is growing rapidly in content, scope, and value. This role is due to the evolution and expansion of our web services and products to enable this growth. We make a real difference to scientific research and to cancer patients around the world.

We provide excellent opportunities to apply best practices in software development, writing clean code and taking a test-driven development approach.

COSMIC data is gathered from a variety of sources, from manual curation to structured repositories into our databases. This position will help provide new websites, generate interactive visualisations of curation data. More about COSMIC here.

Other Information:

Application Process:

As part of your application, please:

1. Upload your CV
2. Complete the following application form: https://forms.gle/mDHbevJbfNqd7VKa6

To ensure your application is considered, please complete all screening questions; incomplete submissions will be automatically declined.

Salary per annum: £38,219 - £45,000 Role Profile

Software Developer job family: Grade 3

Contract Type: Permanent

Recruitment Process: Shortlisting w/c 4th May, Screening interview w/c 11th May, Campus Interviews w/c 25th May or w/c 1st June

Closing date: 3rd May 2026

Hybrid Working at Wellcome Sanger:

We recognise that there are many benefits to Hybrid Working; including an improved work-life balance, with more focused time, as well as the ability to organise working time so that collaborative opportunities and team discussions are facilitated on campus. The hybrid working arrangement will vary for different roles and teams. The nature of your role and the type of work you do will determine if a hybrid working arrangement is possible.