Outlook Add-in Development Company
Outlook Add-in Development Expertise
For 25+ years, we have built software for Microsoft Outlook. Today we also run our own product, Outlook4Gmail. We take Outlook add-ins from concept to launch and support them afterward. Our Microsoft Outlook add-in development services cover architecture, development, testing, deployment, and maintenance.
Our Microsoft Outlook Plugin Development Means:
- New and classic Outlook, web, Mac, and mobile
- VSTO to Office.js migration
- CRM, ERP, and Microsoft Graph integrations
- Event-based and pre-send automation
- Security-first development
Outlook Add-in Development Services
Our team specializes in making purpose-built Outlook add-ins that integrate with your existing systems and match your distinct requirements. They can be everything from simple integrations to complex enterprise-grade solutions.
Custom Outlook Add-in Development
We build Outlook add-ins with task panes and ribbon commands for read and compose scenarios. Depending on the requirements, we use Office.js to create modern, cross-platform add-ins, or VSTO for Windows-specific functionality and deeper integration with classic Outlook for Windows.
VSTO and COM Migration for the New Outlook
We help modernize VSTO and COM add-ins for the new Outlook by reviewing existing functionality and rebuilding supported features in Office.js. For example, COM ItemSend logic can be replaced with event-based activation using OnMessageSend and Smart Alerts, where supported. Some features may need alternative solutions due to differences between Office.js and VSTO/COM.
CRM, ERP and Third-Party Integrations
We integrate Outlook with Salesforce, HubSpot, Dynamics 365, SAP, CRM and ERP systems, cloud storage, and collaboration tools. For Microsoft 365 integrations, we use Microsoft Graph API to connect Outlook with Teams, SharePoint, OneDrive, and enterprise applications.
Email Automation and Smart Alerts
We use Outlook event-based activation to automate email composition and sending. Add-ins validate emails, insert signatures, apply templates, and enforce business rules. Smart Alerts can warn users or block messages with missing attachments, unapproved recipients, or other validation issues. Availability depends on the Outlook client and supported APIs.
Cross-Platform and Mobile Add-ins
We adapt each add-in to the capabilities of its target Outlook clients, including mobile, where supported features and APIs may be more limited. When server-side processing is required, we build C# and .NET backends for APIs, business logic, authentication integration, and data connectivity.
Maintenance and Support
We provide bug fixes, performance tuning, compatibility updates, and changes required by new Outlook and Microsoft 365 APIs. We also help replace legacy EWS-based integrations with Microsoft Graph as Microsoft moves Outlook development toward its current API stack.
Is Your Outlook Add-in Ready for the New Outlook?
Microsoft is moving Windows users to the new Outlook, where COM and VSTO add-ins are not supported. Office.js add-ins work in both the new and classic Outlook and across other supported platforms.
Microsoft is also retiring Exchange Web Services (EWS) in Exchange Online: since October 1, 2026, it is blocked by default unless an admin allow-lists the app, and it will be removed permanently after April 1, 2027. Add-ins that depend on EWS should be migrated to Microsoft Graph.
Office.js add-in
VSTO / COM add-in
Classic Outlook for Windows
Supported
Supported
New Outlook for Windows
Supported
Not supported
Outlook on the web, Mac
Supported
Not supported
Outlook for iOS and Android
Supported with a limited API set
Not supported
Microsoft Marketplace
Can be published
Cannot be published
Types of Microsoft Outlook Add-ins We Develop
We provide custom software for a wide range of needs, from simple tools that save minutes every day to complex enterprise-grade solutions that connect Outlook with your existing systems:
We can create add-ins that pull customer details from different CRMs, such as Salesforce, HubSpot, or Dynamics 365, directly into Outlook. This lets your team view client history, track running deals, automatically log emails, and update CRM records without switching applications.
Email Tracking and Analytics Tools
Also, we build add-ins (if needed, with the help of AI) that can track when emails are opened, links are clicked, or attachments are downloaded. These tools can send live notifications to your team, display detailed engagement statistics, and integrate with sales dashboards to help refine outreach strategies.
Task and Calendar Management Extensions
Our Outlook add-ins can help users create and manage tasks, calendar events, and Teams meetings without leaving their inbox. Depending on the add-in and its integrations, users can connect to services such as Microsoft To Do, Planner, Jira, Azure DevOps, and Trello to create or update work items, assign them, and link due dates to calendar events. Available features and sync behavior depend on the connected service and integration.
Secure File Sharing and Encryption Add-ins
We build Outlook add-ins that make sensitive file sharing more secure with end-to-end encryption, password protection, access controls, and time-limited download links. We also connect Outlook to secure storage and support industry-specific security requirements.
Collaboration Tools
We integrate Outlook with Microsoft Teams, Slack, Trello, and other collaboration platforms. Users can therefore share emails, attachments, and meeting details, create tasks or discussion threads, and move information from the inbox into shared workspaces without switching between applications.
Pre-Send Validation and Compliance Add-ins
We build Outlook add-ins that automate email workflows from message processing to pre-send checks. With these tools, you can easily categorize emails, create follow-up reminders, extract data, route requests, trigger actions in connected business systems via APIs, and validate recipients, attachments, and sensitivity labels before sending.
Trusted Software Development Company
For over 25 years, SCAND has been delivering secure, high-load software solutions for startups, SMBs, and global enterprises (including NASA, IBM, Cisco, FedEx, Bank of America, Siemens, and others). Our dedicated development teams support clients at every stage of the software development process — from idea and consulting to maintenance and support.
How We Build Outlook Add-ins
Our Outlook add-in development services follow five steps, from discovery and design to deployment and ongoing support.
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2. UX Design
We design the add-in around Outlook workflows using Fluent UI principles. Task panes, commands, and interaction flows are adapted for reading and composing emails, with attention to limited screen space and consistent behavior across supported Outlook clients.
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3. Development
Depending on the project, we build with Office.js or VSTO and connect the add-in to Microsoft Graph and external APIs. For Microsoft 365 environments, we can implement SSO and authentication through Microsoft Entra ID.
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4. Testing
We test functionality, UI behavior, permissions, and integrations across the required Outlook environments, including new and classic Outlook for Windows, Outlook on the web, Mac, iOS, and Android, accounting for platform-specific API limitations.
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5. Deployment and Support
We prepare your add-in for Microsoft Marketplace (formerly AppSource) review and guide you through the submission in Partner Center. For internal solutions, we support centralized deployment through the Microsoft 365 admin center. After release, we handle fixes, compatibility checks, and updates required by changes to Outlook, Office.js, Microsoft Graph, and related APIs.
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1. Discovery
We define user scenarios, target Outlook versions, integration requirements, and IT constraints. This includes authentication, SSO, data access, security policies, deployment model, and any Microsoft 365 or third-party systems the add-in needs to work with.
Benefits of Custom Outlook Add-ins for Your Business
A well-designed Outlook add-in can save hours of manual work every week and create faster task completion in your organization.
- 1
Fewer Hours Spent on Daily Workflows
By automating repetitive tasks, such as sorting emails, sending template replies, or scheduling follow-ups, you free up your staff’s time to focus on more important work and reduce stress caused by monotonous, time-intensive activities.
- 2
Minimization of Data Entry Errors
Automatically syncing data between Outlook and your CRM, ERP, or other systems means fewer manual mistakes. This, in turn, maintains precise customer and project records, helps you avoid costly errors, and makes it easier for teams to access the right data when they need it.
- 3
Better Sales and Customer Engagement
With email tracking and live notifications, your sales team knows exactly when customers open messages or click links. Such visibility lets you follow up at the right moment, increase your chances of closing deals, and strengthen partnerships.
- 4
Same Great Experience on All Devices
A custom Outlook add-in can provide a consistent core experience across Windows, Mac, web, and mobile, with platform-specific limits on iOS and Android. Users can switch between devices more easily and access the same core functionality wherever they work.
Technologies We Use
When developing software, we use trusted and modern tools to make Outlook add-ins that work exactly as demanded and do what you need them to.
Languages & Frameworks
- C#
- .NET
- JavaScript
- TypeScript
- Office.js
- React
- Angular
- Fluent UI
- VSTO
- WPF
Integrations
- Microsoft Graph
- Microsoft Entra ID for SSO and nested app authentication
- Exchange Online
- Unified manifest
- Azure
- REST APIs
Platforms
- Outlook for Windows (new and classic)
- Outlook on the web
- Outlook for Mac
- Outlook for iOS and Android
Built by Experts. Accelerated by AI.
We can enhance your solutions with AI tools where they bring real value or leave development completely traditional.
Industry Focus
We build custom add-ins that are not just generic tools, but personalized software made to suit the exact flow of your business tasks, compliance standards, and specific industry process difficulties.
For finance and banking, we create add-ins that automate client communication, generate and send financial reports directly from Outlook, integrate with accounting software like QuickBooks or Xero, and support multi-step approval processes for transactions.
In healthcare, we make HIPAA-compliant add-ins that let medical staff safely share patient records, schedule telehealth appointments, process lab results, and integrate Outlook with EHR systems, such as Epic or Cerner. Our automations also help track follow-ups and patient reminders without risking compliance breaches.
For legal service providers, we develop add-ins that help manage case-related emails, link correspondence to specific matters, schedule court dates, and share documents with clients. With integration to document management systems, every attachment is automatically filed in the correct case folder.
For sellers, we develop add-ins that pull order details from the CRM into Outlook, automate customer support replies, send shipping updates from emails, and sync communications with Shopify or Magento platforms. We can also embed generative AI/LLM to make personalized offers based on client purchase history.
Real estate agents can benefit from add-ins that can track property inquiries, sync email leads to CRM systems, schedule property viewings, and send automated follow-ups. Additionally, we can set up seamless integration with MLS databases so agents can send updated listings directly from their inbox.
For manufacturers, we offer add-ins that coordinate supplier communications, provide automated order confirmations, track shipment statuses, and link Outlook with ERP systems, such as SAP or Oracle NetSuite. Besides, we can build in alerts and reminders to help teams prevent production delays.
Outlook4Gmail – Our Outlook Add-in Product
One of our flagship products, Outlook4Gmail, is a multi-featured Outlook add-in made to coordinate Outlook and Google services. With it, you can automatically sync Outlook and Gmail accounts’ contacts, calendars, and tasks, so you don’t need to import or export them manually. Outlook4Gmail is ideal for professionals and businesses that rely on both Microsoft and Google ecosystems.
Major features include:
- Two-way synchronization of contacts, calendars, and tasks
- Multi-account support for syncing data in several Outlook and Gmail profiles
- Custom sync settings to control what and how often data is updated
- Invisible background operation without interrupting your work
Hire Outlook Add-in Developers
Hire Outlook add-in developers with experience in Office.js, VSTO, Microsoft Graph, Microsoft Entra ID, and Microsoft 365 integrations. Our team can join at any stage, from architecture and development to migration, testing, deployment, and ongoing support.
Related Cases
- .NET
- C#
- JavaScript
- VSTO
- Outlook
- Web
- Microsoft 365
- Office 365
- .NET
- JavaScript
- React
- Node.js
- Desktop
- PowerPoint Add-in
- Microsoft Add-ins
- Microsoft Office Add-in
- .NET
Latest Reviews from Our Clients
Sr. Account Director Mid-Market
Coupa Deutschland GmbH
It was a great experience working with SCAND on e-Procurement projects during my time at OpusCapita. The team was professional and competent. Keep up the great work!
Managing Director
prodexa GmbH
The SCAND team has been an incredibly reliable and skilled development partner for jCatalog for many years, consistently delivering high-quality services with a proactive approach.
Product Manager
jCatalog Software AG (or OpusCapita GmbH)
Over the years of working together, the SCAND team has always been a reliable pillar of support for me. Along the way, we’ve built not only a strong professional relationship but also meaningful personal connections. It has truly been a pleasure collaborating with you.
Outsourcing Manager at Owlcat Games
Working with SCAND on customizing SourceGit was a genuinely positive experience. Their team was responsive, collaborative, and easy to work with throughout the project. We value their cooperative approach and would confidently recommend them as a reliable development partner.
Managing Product Owner at GIPmbh
We have been working with SCAND on the development of a custom Outlook Add-In that converts documents directly from Outlook and transfers them seamlessly into our software platform. We highly recommend them to anyone looking for a skilled and dependable software development team...
Chief Technology Officer
Wiztech Group
Great work on our products — web applications in the gaming domain. The SCAND software developers worked highly professionally and made valuable contributions to the successful implementation of every project they were involved in.
Sales & Marketing Manager, Smartstaff AS
Throughout our long-standing collaboration, the team has consistently delivered high-quality service. Over time, we’ve developed a strong and genuinely friendly working relationship, which has positively influenced the outcomes of our joint efforts.
Founder at Spin Pass
SCAND went above and beyond, and I was very satisfied with the result. Their team was communicative, patient, and took the time to fully understand the project. Above all, they were professional and easy to work with, and I would definitely recommend SCAND for their expertise and software development skills.
Founder of TreeNinjaAI
What might have taken 18 months was completed in about 6, with SCAND contributing for 3.5 months. Despite my non-engineering background, their support and modern AI capabilities enabled us to build unique features and integrations in a single application.
FAQs
