Office Add-ins: The Future of Workflow Automation
Explore the latest trends and innovations in Office Add-ins, from AI-powered automation to seamless integration with Microsoft 365.
Read moreMicrosoft 365 Certified Solutions
Microsoft Office Add-in Development
Certified Office.js add-ins for Excel, Outlook, Word, and Teams. Delivered in 2 to 8 weeks for enterprise teams across the US, UK, and Australia.
350+Projects Delivered
5+Years Experience
MicrosoftPartner Network
98%Client Satisfaction
Trusted by finance, legal, healthcare & logistics teams worldwide
What We Do
Custom Microsoft Office Add-ins using Office.js for Excel, Outlook, Word, PowerPoint, SharePoint, and Teams. Delivered in 2 to 8 weeks for enterprise clients worldwide.
Office Add-ins Development
MSOfficeAddin builds custom Microsoft Office add-ins for Excel, Outlook, Word, PowerPoint, SharePoint, and Teams using Office.js and the Microsoft 365 platform. From CRM-integrated Outlook add-in workflows to financial-automation Excel tools, our certified developers deliver AppSource-ready, cross-platform solutions for enterprise teams across the US, UK, and Australia.
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Authentication & Identity
Secure authentication development services including Microsoft SSO, Azure AD, OAuth 2.0, OpenID Connect, MFA, and role-based access control for web and enterprise Office 365 applications.
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AppSource Publishing Services
End-to-end Microsoft AppSource publishing and certification support for Office add-ins. We handle code review, manifest optimization, compliance validation, and submission — getting your add-in approved on the first attempt.
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Excel Add-ins Development
MSOfficeAddin specializes in excel add-in development using Office.js, React, and TypeScript — building production-grade Excel extensions, data analysis tools in Excel, and automation add-ins for enterprise teams worldwide. From custom excel ribbon customization that puts your most-used business logic one click away, to API-connected task panes that pull live figures from your ERP without leaving the spreadsheet, every solution is cross-platform, AppSource-certified, and built to scale.
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Outlook Add-ins Development
MSOfficeAddin builds custom outlook add-ins using Office.js, React, and TypeScript — from crm for outlook integrations that sync every customer interaction directly from the inbox, to email automation workflows and calendar add-ins that connect Microsoft 365 to your business systems. Whether you need a CRM connector, a support ticketing tool, a Teams-bridging solution, or a cross-platform enterprise deployment, we scope, build, and AppSource-certify it.
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PowerPoint Add-ins Development
Custom PowerPoint add-in development for slide automation, branded presentation generation, and design system integration. We build Office.js PowerPoint add-ins for enterprise consulting, sales, and marketing teams — AppSource-ready.
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SharePoint Add-ins Development
Custom SharePoint add-in development and SPFx web part development for intranet automation, document management, and enterprise portal solutions. Specialist SharePoint developers for Microsoft 365 and SharePoint Online.
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Teams Add-ins Development
Custom Microsoft Teams add-in development — tab apps, bots, messaging extensions, and meeting apps built for enterprise collaboration workflows. Specialist Teams app developers for Microsoft 365.
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Why Choose Us
500+ Office Add-in projects delivered since 2015. 98% client satisfaction. AppSource-certified publisher. Microsoft Partner Network member. Office.js and Azure specialists with 10+ years of Microsoft 365 development experience.
500+Projects Delivered
98%Client Satisfaction
10+Years Experience
PartnerMicrosoft Network
Fast Delivery
Simple task-pane add-ins ship in 2–3 weeks. Complex Graph-integrated solutions ship in 6–10 weeks. Every project includes a delivery milestone schedule.
Enterprise Security
Azure AD / Microsoft Entra ID SSO, MSAL.js On-Behalf-Of (OBO) flow, and Microsoft Graph security scopes implemented on every enterprise project.
Expert Team
Office.js specialists with 10+ years building AppSource-certified add-ins. We have completed 50+ VSTO-to-Office.js migrations for enterprise clients.
Technologies We Master
Office.jsReactTypeScriptAzureMS GraphApps ScriptNode.js
What Our Clients Say
Join 500+ businesses who trust us with their critical Office automation and enterprise add-in development.
"The Excel add-in developed by this team transformed our data reporting workflow. What used to take 4 hours now happens in minutes with 100% accuracy."
J
John SmithCTO, TechCorp Solutions
"Expert knowledge of the Microsoft Graph API. They built a seamless Outlook integration that helped our sales team sync CRM data without leaving their inbox."
S
Sarah JenkinsOperations Manager, Global Logistics
"Navigating AppSource certification is tough, but they handled everything. Our Word add-in was approved on the first try thanks to their clean code."
M
Michael ChenProduct Lead, Innovate Edu
How we build for Microsoft 365
A structured, compliant, and performance-focused development lifecycle aligned with Microsoft AppSource standards.
STEP 01
Planning & Analysis
Gathering stakeholder requirements and defining scope against Office JS API capabilities.
STEP 02
Architectural Design
Designing Task Pane interfaces using Fluent UI components for a native Microsoft experience.
STEP 03
Development
Iterative coding of manifests and web logic with real-time Office sideloading tests.
STEP 04
QA & Security
Rigorous bug identification and validation against Microsoft security standards.
STEP 05
Deployment
Global rollout via AppSource or centralized tenant deployment via M365 Admin Center.
STEP 06
Maintenance
Ongoing monitoring and compatibility updates for new Microsoft 365 releases.
From the Blog
Microsoft SSO and Azure AD in Office Add-ins
Implement Single Sign-On and Azure AD authentication in your Office Add-ins for a seamless, secure user experience.
Read moreExcel Add-ins: Automate Data and Workflows with Office.js
How to build Excel add-ins that automate data entry, analysis, and reporting using Office.js and the Excel JavaScript API.
Read moreGetting Started with Office Add-ins: A Developer's Guide
Learn the fundamentals of building Microsoft Office Add-ins with Office.js, from project setup to deployment and AppSource publishing.
Read moreFrequently asked questions
How do I hire Microsoft developers for custom Office plugins?
Contact us at info@msofficeaddin.com or via the /contact page. We are a Microsoft Partner Network member with 350+ Office Add-in projects delivered over 5 years. Project quotes are returned within 24 business hours. Engagements start from $3,000 USD.
What is the difference between an Office Add-in and a COM Add-in?
Office Add-ins use HTML, CSS, and JavaScript via the Office.js API. They run cross-platform on Windows, macOS, and Outlook on the Web with no local installation required. COM Add-ins are legacy .NET/Windows-only extensions requiring administrator rights and do not run on Mac or Web. Microsoft has deprecated COM add-in development in favour of Office.js.
Next Steps
Modernize your enterprise with custom Office solutions.
Work with certified Microsoft developers to bridge the gap between your unique data and the tools your team uses every day.
Why start now?
- Reduce manual data entry by up to 80%
- Deploy secure SSO-ready add-ins
- Azure-backed infrastructure
Quick Contact
info@msofficeaddin.comContact us
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info@msofficeaddin.com
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Consultation
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Global Support
Working with clients across North America, Europe, and Asia.