Senior Outlook Add in Developer | £500-£550p/day (Inside IR35) | S.Yorkshire | (Hybrid, 2/3 days in office) | 10 month contract Our client is looking for a experienced Outlook Add-in Developer to help support add-in solutions within a enterprise scale messaging environments. The focus of the role will be building robust, cross platform Outlook add-ins that perform across Windows, macOS, web and mobile clients. It'll be an exchange landscape that's both on-premises infrastructure and Microsoft 365, where you will collaborate closely with engineering, product and operations teams in an agile delivery model. What you'll be doing: Architecting, developing, and enhancing Outlook add-ins using modern Microsoft frameworks and tools Ensuring add-ins deliver a consistent experience across all Outlook clients, including desktop, browser, and mobile Connecting add-ins to backend systems, APIs, and identity services such as Microsoft Graph and Azure Active Directory You'll be working closely with product owners, architects, QA, and operations Maintaining compatibility across Exchange on-premises and Exchange Online deployments Producing and maintaining technical documentation, design guidelines, and development standards What we're looking for: You can demonstrate experience delivering Outlook add-ins within enterprise environments Strong hands on skills with Office.js, JavaScript or TypeScript, HTML, and CSS Deep understanding of Microsoft 365, Exchange Online, and the behavioral differences between Outlook clients Experience integrating with Microsoft Graph, RESTful APIs, and modern authentication methods (OAuth / Azure AD) Nice to have: Exposure to CI/CD pipelines, Git-based version control, and automated testing practices Experience with Azure services such as App Services, Functions, Storage, or Key Vault Candidates will be required to go through background checks before commencing contract. Must be eligible to live and work in the specified work location. Some occasional travel maybe required. Only successful candidates will be contacted. EQUAL OPPORTUNITIES Our client is committed to equal opportunities and actively seeks applications from all sectors of the community irrespective of sex, race, colour, nationality, ethnic or national origin, disability, marital status, sexual orientation, having responsibility for dependents, age, religion/beliefs, or any other reason which cannot be shown to be justified If this sounds like a good fit, apply now! Senior Outlook Add in Developer | £500-£550p/day (Inside IR35) | S.Yorkshire | (Hybrid, 2/3 days in office) | 10 month contract Oscar Associates (UK) Limited is acting as an Employment Business in relation to this vacancy. To understand more about what we do with your data please review our privacy policy in the privacy section of the Oscar website.