Senior Software Engineer (Full Stack)

About the role

We are looking for an exceptional Senior Full Stack Engineer to reshape how legal professionals access and understand complex documents. In this role, you will lead the design, development, and optimisation of our next generation LegalTech products, with a strong emphasis on .NET backend engineering, scalable system design, and high performance integrations with Microsoft platforms.

You’ll work across both frontend and backend technologies, but you’ll play a key role in strengthening and modernising our .NET services, improving system reliability, and building clean, maintainable architectures that support our growing AI-driven product suite. You will also contribute to the evolution of our OfficeJS Word add-ins and modern JavaScript tooling where needed. This role is ideal for someone who thrives in a product-led environment, enjoys solving complex engineering challenges, and wants to help guide our transition from legacy .NET components to a more modular, cloud-ready architecture.

What you'll do:

• Design, build, and scale high performance backend services using .NET (C#)

• Contribute to frontend features using React, TypeScript, and modern JavaScript tooling

• Architect modular, scalable systems that integrate with OJS, Microsoft Word, and cloud environments (Azure/AWS)

• Optimise performance, reliability, and observability across new and existing .NET services Modernise legacy .NET components and help drive best practices in API, service, and data design

• Collaborate closely with Product, Design, and Engineering to deliver impactful, user focused features

• Lead code reviews, evolve engineering standards, and mentor other engineers

• Champion engineering best practices (SOLID, DRY, TDD) and leverage AI-assisted tooling to accelerate development

What you'll bring:

• 4+ years of professional experience as a Full Stack or Backend Engineer

• Deep expertise in .NET/C#, ASP.NET Core, and backend API development

• Proven ability to design and build scalable, production-ready systems

• Strong frontend development skills with React, JavaScript/TypeScript, HTML5, and CSS3

• Experience integrating with RESTful and GraphQL APIs

• Familiarity with relational databases such as PostgreSQL, SQL Server, or similar

• Experience with DevOps workflows, CI/CD, and cloud deployments

• Strong understanding of Git, testing practices, and agile delivery

• Excellent communication and collaboration skills, with a product mindset

We’ll be lucky if you have:

• Experience at high-growth startups or AI-driven product companies

• Prior work in LegalTech, AI, or document-focused workflows

• Experience with cloud-native architectures or microservices

• Familiarity with modern cross-platform frameworks like .NET MAUI, Blazor, or Electron

• A track record of mentoring engineers or driving architectural transformations

What we offer:

• Competitive salary & annual bonus

• Equity in Definely

• Quarterly team socials & annual company offsite

• Hybrid working (Tues & Thurs in-office) + 🌍 1 month “work from anywhere”

• 25 days holiday + bank holidays

• £750 annual learning & development budget

• Private healthcare (incl. dental & optical)

• Enhanced parental leave

• Additional perks: Cycle to Work, Workplace Nursery salary sacrifice scheme, and top-quality equipment.

About Definely

At Definely, we’re on a mission to simplify the way legal professionals access and understand complex information in legal documents. Trusted by a global community of customers, our LegalTech solutions integrate seamlessly into lawyers' daily workflows, making it easier to draft, review and navigate even the most complex contracts.

Our products provide instant access to essential information, enabling legal teams to review clauses and provisions in context, reduce risk and work more efficiently – all without disrupting their flow. At Definely, we’re dedicated to solving real challenges faced by legal professionals.

Joining Definely means becoming part of a forward-thinking, collaborative team that prioritises innovation and people. We create a supportive environment driven by a shared commitment to connection, growth and success.

Recognised in the top 25 of Deloitte's prestigious UK Technology Fast50 in 2023 and backed by Microsoft, Google and Octopus Ventures, we’re trusted by leading law firms and in-house legal teams, including A&O Shearman, Dentons, Deloitte, and Barclays, to streamline their workflows and mitigate risks.

Data Privacy Notice

By submitting your application, you agree that DEFEYENE LEGAL SOLUTIONS LIMITED ('Definely') may collect, process, and store your personal data as part of our recruitment process. We will use the information you provide to assess your qualifications for the role you are applying for and to communicate with you regarding your application.Your personal data will be stored for up to 12 months, after which it will be securely deleted unless we have another lawful basis to retain it. You have the right to access, correct, or request the deletion of your data at any time
If you have any concerns about how your data is being processed, please do not hesitate to contact us.