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Overview

We’re looking for a Senior Engineer with strong technical depth and a passion for building exceptional user experiences. You’ll play a key role in shaping our front-end architecture, collaborating closely with product and design teams, and delivering scalable, performant solutions used by legal professionals worldwide. As a senior member of the team, you’ll act as a technical expert and a trusted partner helping to guide best practices, influence decisions, and mentor others through collaboration and example.

What you’ll do

• Design and build sophisticated React applications integrating with Microsoft Word, M365, and other Office products using Office.js.
• Write clean, scalable, and maintainable code while driving performance and reliability.
• Collaborate with product, design, and engineering teams to deliver user-focused, accessible features.
• Contribute to architectural discussions and help shape the evolution of our tech stack.
• Mentor and support team members through knowledge sharing, code reviews, and best practice guidance.
• Troubleshoot complex technical challenges and drive continuous improvement through automation and AI-assisted workflows.
• Maintain high-quality standards with robust testing, documentation, and security practices.

What you’ll bring

• 4+ years of hands-on experience building production React applications.
• Strong proficiency in React, TypeScript, JavaScript, HTML, CSS, and modern web technologies.
• Experience integrating with Microsoft Office, especially Office.js and Word add-ins.
• Familiarity with agentic coding assistants such as Claude Code or similar AI tools.
• Excellent communication and collaboration skills in English.
• Proven ability to work independently while contributing effectively to team goals.
• Experience working successfully in hybrid or remote development environments.
• Solid understanding of React performance optimisation (e.g. memoisation, code splitting, avoiding unnecessary re-renders).
• Experience with Git, version control best practices, and CI/CD pipelines.

We’ll be lucky if you have

• Knowledge of Microsoft Office Add-in guidelines and Office Store submission processes.
• Experience optimising in-browser text editors for speed and responsiveness.
• Prior experience in product-focused or startup environments.
• Exposure to AI-powered developer tools and automation workflows.

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. We create a supportive environment driven by a shared commitment to connection, growth and success.

Data Privacy Notice

By submitting your application, you agree that Definely may collect, process, and store your personal data as part of our recruitment process. 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, please contact hr@definely.com.

Seniority level

• Mid-Senior level

Employment type

• Full-time

Job function

• Engineering and Information Technology

Industries

• Software Development