Office.js Developer
Senior Outlook Add-In Developer (Office.js) | Hybrid | London / Sheffield | 10 Month Contract | £500 - £550 inside IR35
About the Role
We’re looking for a Senior Outlook Add-in Developer to join our team and take ownership of designing, building, and supporting Outlook add-ins used in large, enterprise-scale environments.
This role is ideal for someone who thrives in complex messaging ecosystems and has hands-on experience delivering solutions that work flawlessly across Windows, macOS, web, and mobile Outlook clients, including hybrid Exchange setups spanning on-premises and Microsoft 365.
What You’ll Be Doing
- Architect, develop, and support Outlook add-ins using Office.js and modern web technologies
- Ensure add-ins perform consistently across Outlook for Windows, Mac, Web, and Mobile
- Integrate Outlook add-ins with backend services, APIs, and identity platforms such as Microsoft Graph and Azure
- Focus on performance, security, and reliability in high-volume email scenarios
- Diagnose and resolve issues across multiple Outlook clients and platforms
Core Technical Experience
- Demonstrated experience building Outlook add-ins in enterprise environments
- Strong skills in Office.js, JavaScript/TypeScript, HTML, and CSS
- Hands-on experience with hybrid Exchange (on-prem + Exchange Online)
- Solid understanding of Microsoft 365, Outlook desktop clients, and Outlook Web App behaviour
Nice to Have
- Experience with Azure services (App Services, Functions, Storage, Key Vault)
If this sounds like you, APPLY NOW!
Senior Outlook Add-In Developer (Office.js) | Hybrid | London / Sheffield | 10 Month Contract | £500 - £550 inside IR35