We are looking for an exceptional Senior Full Stack Engineer to to reshape how legal professionals access and understand complex documents.
In this role, you will drive the design, development, and optimisation of our next generation LegalTech products built on OJS and modern JavaScript frameworks. You will work across both the frontend and backend, building rich, performant user experiences and scalable services, while also leveraging knowledge of .NET principles to enhance and extend our existing backend systems.
While we are gradually transitioning away from a .NET-heavy stack, we’re looking for engineers who can contribute to that journey; people who love modern JavaScript development and are equally comfortable diving into existing .NET code when needed.
You’ll also shape architecture and define engineering best practices that enable performance, maintainability, and innovation.
What you'll do:Build and scale high performance web applications using React, TypeScript, and modern frontend tooling
Develop robust backend services in JavaScript (and ideally contribute to existing .NET services)
Design modular, scalable architectures that integrate with OJS, AWS, and Azure cloud platforms
Optimise system performance and ensure seamless interaction between new and legacy components
Lead code and architecture reviews, mentor other engineers, and promote technical excellence
Collaborate closely with product and design teams to deliver impactful, user focused features
Champion engineering best practices (SOLID, DRY, TDD) and leverage AI assisted tools to accelerate delivery
4+ years of professional experience as a Full Stack JavaScript Engineer
A degree in computer science or a related engineering discipline
Deep expertise in React, JavaScript/TypeScript, HTML5, and CSS3
Strong backend development experience using JavaScript (and ideally familiarity with .NET)
Proven ability to architect, build, and scale modern web applications
Experience integrating with RESTful and GraphQL APIs
Familiarity with relational databases such as PostgreSQL and modern DevOps workflows
Strong understanding of Git, CI/CD, and agile delivery processes
Excellent communication and collaboration skills; you thrive in a fast paced, product driven environment
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
💰 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
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.For more details on how we handle your personal data and your rights, please send us an email to [email protected] and we will send your our privacy policy.
If you have any concerns about how your data is being processed, please do not hesitate to contact us.
Top Skills
What We Do
Named as one of the 50 fastest growing tech companies in the UK by Deloitte in 2023, Definely addresses the number one issue associated with drafting, reviewing and understanding legal documents. With Definely, you no longer need to ctrl+f, print out a legal document or scroll endlessly just to access the information (defined terms and cross-references) you need to understand the clause or provision being reviewed. Delivered as an MS Word Plugin, Definely is easy to use, integrates effortlessly into your current workflows and does not require any complex IT processes to get up and running.
