Hire Microsoft Office Add-Ins Developers

Cost depends on what you are building. A simple, single-feature add-in for one Office app costs far less than an enterprise-grade build with multiple CRM or ERP integrations. We offer three engagement models-hourly, dedicated developer, and fixed-price-each with its own pricing structure. Hourly rates start from $40/hr and vary based on developer seniority and project complexity. The most accurate way to get a number is a free requirements call - we quote based on your actual project, not a generic price list.

It depends on your scope. A focused, single-feature add-in with no external integrations can be ready in a few weeks. Projects with CRM or ERP connections take longer. Enterprise builds with AppSource certification take longer still. After a quick requirements call, we give you a real milestone plan with actual delivery dates - not a vague estimate. You also get working, testable builds at every milestone, so there are no surprises at handover.

For any new add-in, Office JavaScript API (Office.js) is almost always the right choice. It runs on Windows, Mac, and the browser from one codebase - no separate versions needed. VSTO is an older technology, and no new features are being added to it. The new Outlook for Windows has also removed VSTO support completely. Microsoft is putting all future add-in investment into Office.js. We work with both and recommend the right one based on your environment, not a commercial preference.

Yes - and it is one of the most common things businesses are coming to us for right now. The new Outlook for Windows no longer supports VSTO or COM add-ins, so teams relying on them are either already affected or will be soon. We review your existing add-in, map each feature to its Office.js equivalent, and migrate it without rebuilding everything from scratch whenever possible. The result works in the new Outlook, on Mac, and in the browser. We offer a free assessment if you are not sure whether your add-in is at risk.

You own everything - fully and permanently. Every line of code we build belongs to you with no licensing fees and no retained rights. We sign a mutual NDA before any project details are shared - not after the scoping call, before it. Your idea and business information are protected from the very first conversation. If you want to work inside your own GitHub repository throughout the build for full visibility at every stage, we are happy to do that too.

Yes - connecting Office add-ins to external business systems is one of the most common things we build. We have delivered integrations with Salesforce, SAP, Microsoft Dynamics 365, HubSpot, and custom internal systems using REST APIs and Microsoft Graph API. If your system has an API, we can connect to it. If you are not sure whether yours supports this kind of integration, bring it up in the first call and we will give you a straight answer.

Yes. Every project includes post-launch support to cover bugs and any issues caused by new Office updates - Microsoft releases changes regularly and they can sometimes affect how add-ins behave. We make sure yours keeps working. If you need ongoing development after that - new features, integration changes, or updates as your systems evolve - we offer flexible arrangements based on what you actually need. We agree on this before the project starts, not as an afterthought after you are live.

For modern, cross-platform add-ins we use Office JavaScript API (Office.js) with TypeScript and React. For legacy or Windows-only environments, we develop and maintain solutions using VSTO and .NET/C#. For integrations with Microsoft 365 data - Outlook, SharePoint, Teams, OneDrive - we use Microsoft Graph API. On the tooling side we use Visual Studio, VS Code, and the Yeoman Office Generator. The right stack depends on your environment and we walk you through the recommendation before any development starts.