Senior Developer (.NET/React) in London

Department: Technology

Employment Type: Permanent

Location: London, UK

Reporting To: Engineering Manager

Description

We see a world where we all contribute to a thriving planet and together, we are a collective force for good. Planet Mark is a sustainability certification which recognises outstanding achievements, encourages action, and builds an empowered community of like‑minded individuals. We work with businesses to rigorously measure their carbon footprint and social value, engage their staff and supply chain to unlock their knowledge and drive passion for change, and communicate their progress to build a positive brand. We help businesses put a purpose at the heart of their organisation that brings social, environmental, and economic considerations together.

What that means day to day

• Key Responsibilities
• Technical Direction & Architecture Collaboration: Work closely with the central architecture team to shape the technical direction of the product, contributing to architectural decisions and ensuring alignment with enterprise standards. Play a key role in delivering a greenfield project.
• Full Stack Development: Build scalable back‑end services using .NET Core and responsive front‑end components using React.
• AI‑Assisted Engineering (Core Expectation): Champion the use of GitHub Copilot as a fundamental part of day‑to‑day development. Use AI tooling to accelerate delivery, improve code quality, and influence team practices around effective prompting and AI‑assisted workflows.
• DevOps Practice: Actively utilise Azure DevOps, managing repository pull requests and configuring CI/CD build and release pipelines.
• Database Management: Design, optimise, and maintain efficient document schemas and queries in MongoDB.
• Integration Support: Integrate with Microsoft Dynamics CRM to streamline business workflows and data synchronisation.
• Code Quality & Governance: Write clean, testable code and participate in peer code reviews, ensuring all AI‑assisted output meets strict security and architectural standards.

What you’ll need to be successful

• Essential Criteria (Must‑Haves)
• Architecture Collaboration: Experience working with architecture functions to influence and implement technical direction, particularly within greenfield or early‑stage products.
• AI Tooling Leadership: Strong, hands‑on experience using GitHub Copilot (or equivalent) as a core part of development, with the ability to demonstrate how AI can materially improve productivity and code quality.
• Back‑End Expertise: Strong proficiency in C# and the .NET framework (.NET Core / .NET 6+).
• Front‑End Expertise: Proven professional experience building modern, component‑based web applications with React.
• DevOps Knowledge: Solid understanding of Azure DevOps (Repos and Pipelines) for agile task tracking and code management.
• Database Experience: Hands‑on experience working with MongoDB or other NoSQL databases.
• API Development: Experience building and consuming web services and RESTful APIs.

• Desirable Criteria (Nice‑to‑Haves)
• CRM Familiarity: Experience with Microsoft Dynamics CRM.
• Cloud Infrastructure: Experience deploying and hosting applications directly within Microsoft Azure or AWS.

What you'll get in return

We have a hybrid workplace policy, where you will work from the office 2‑3 days per week. Our office is located at 39 Tabernacle St, London EC2A 4AA, United Kingdom. We want you to be able to do your best work here. We emphasize providing many ways to support our team to do their best work and below are some of the perks and benefits we offer:

• Personal Health & Wellbeing / Benefits
• Enhanced Parental Leave
• Generous annual leave, with the option to buy and sell additional days
• Healthcare Plan
• Annual Giving Day – an extra day to give back to yourself or your community
• Cycle‑to‑work Scheme
• Electric Vehicle Scheme

• Future Planning
• Pension scheme with employer contributions
• Life Assurance – 3X base salary
• Rewards Program – access to discounts and cashback
• LinkedIn Learning License for upskilling & development

We are proudly an equal‑opportunity employer. We are committed to ensuring that no candidate is discriminated against because of gender identity and expression, race, disability, ethnicity, sexual orientation, age, colour, region, creed, national origin, or sex. We are dedicated to growing a diverse team while continuing to create an inclusive environment where everyone feels safe and empowered to be themselves.