Junior Software Developer jobs in United Kingdom

Department: Tech - Software Development

Employment Type: Permanent - Full Time

Location: Oxford, UK

We’re looking for a Model Developer to help us build and maintain the Python codebase behind Aurora’s Origin and Chronos modelling software products. You’ll work in a collaborative engineering environment, owning feature development and improving code quality, maintainability, and developer experience in the model stack used across our business. You will collaborate with your colleagues in the Modelling team to define practical methodologies, with your focus being on turning these approaches into robust, well‑tested, scalable software.

You’ll thrive here if you enjoy writing clean, maintainable Python, shaping libraries and packages other teams rely on, and raising engineering standards (TDD, CI/CD, reviews, readability) across a large, shared codebase.

The position suits an individual with 3+ years of experience in software development who is interested in a career applying software engineering techniques to modelling software solutions.

• Design, implement, and maintain Python modules/packages in the modelling codebase; own components over time and steward their quality and usability for other teams.
• Translate modelling methods into production‑quality code, collaborating with method owners in the Modelling team; ensure implementations are readable, tested, and traceable.
• Improve code quality and developer experience by refactoring for clarity, strengthening interfaces and simplifying implementations.
• Champion automated testing and TDD; driving the adoption of modern software engineering practices in the model development team.
• Participate in code reviews and technical design discussions
• Identifying and addressing architectural bottlenecks and opportunities to improve scalability and developer experience

Required attributes:

• Professional Python experience (3+ years) in a commercial, team‑based software environment, delivering components used by other teams/customers
• Strong software engineering fundamentals
• Comfortable collaborating with Modelling, Research, and Product teams to implement methods as robust, maintainable code; motivated to raise standards for others
• A relevant degree in a quantitative field such as Mathematics, Physics, Engineering, or Computer Science
• An interest in working in the energy/decarbonization sector

Desirable attributes:

• Experience building software using Test Driven Development and Continuous Delivery
• Experience developing modelling or simulation software, or with mathematical optimisation (LPs/MIPs) - particularly in the energy industry
• Experience stewarding internal libraries/SDKs, packaging (pyproject.toml, Poetry/uv) and dependency management at scale
• Experience in managing or mentoring junior colleagues

Some of the benefits we include are:

• Private Medical Insurance
• Dental Insurance
• Parental Support
• Salary-Exchange Pension
• Employee Assistance Programme (EAP)
• Local Oxford Discounts
• Cycle-to-work Scheme
• Flu Jabs

At AER, we are committed to offering flexibility in the way we work. Most of our roles are hybrid with a mix of in-office/home working and potentially adjustable working hours. Let’s discuss what works for you and AER during the interview process.

The Company is committed to the principle that no employee or job applicant shall receive unfavourable treatment on grounds of age, disability, gender reassignment, race, religion or belief, sex, sexual orientation, marriage or civil partnership, pregnancy, and maternity.

To apply, please submit your Résumé / CV, a personal summary, your salary expectations and please inform us of your notice period. Unfortunately, we are unable to accept applications via email, telephone, or social media platforms. To be considered for this position, please submit your application using the link provided. Applications submitted through any other channel will not be reviewed.