Office Add-ins Developer – Roles and Responsibilities

Location: Bangalore

Employment Type: Full Time / Contractual

Experience: 3-6 Years

Primary Skill: C#, .NET, Office Add-ins Development

Secondary Skill: Node.js, JavaScript / TypeScript, Office.js

Work Type: Hybrid / Office as per project requirement

Job Summary

We are looking for an experienced Office Add-ins Developer with strong hands-on expertise in C#, .NET, VSTO / COM Add-ins, and Microsoft Office application integration.

The candidate should be able to design and develop reliable, secure, and high-performance add-ins for Microsoft Office applications such as Word, Excel, PowerPoint, and Outlook. Knowledge of Node.js, JavaScript / TypeScript, and Office.js will be an added advantage for modern Office Web Add-ins development.

Key Responsibilities

Office Add-ins Development

- Design and develop Microsoft Office add-ins using C#, .NET, VSTO, COM Add-ins, and Office Interop APIs.
- Build add-in features for Microsoft Word, Excel, PowerPoint, and Outlook.
- Work with Office object models, Ribbon customization, task panes, event handlers, and document-level operations.
- Develop reusable components and libraries for Office add-in functionality.
- Ensure add-ins are stable, responsive, and compatible with supported Office versions.

C# / .NET Development

- Develop application logic using C#, .NET Framework / .NET, and Visual Studio.
- Work with Office events such as open, save, close, send, attachment handling, and user actions.
- Implement document, email, attachment, and metadata-related workflows.
- Write clean, maintainable, secure, and testable code.
- Participate in technical design discussions and code reviews.

Office Application Integration

- Develop features for Outlook email compose, read, send, and attachment workflows.




- Develop features for Word, Excel, and PowerPoint document processing.
- Handle document properties, metadata, headers, footers, watermarks, labels, and user prompts where required.
- Manage Office application behavior, add-in lifecycle, and event-driven functionality.
- Debug and resolve issues related to Office APIs, COM exceptions, add-in loading, and runtime behavior.

Node.js / Office.js Development

- Develop or support modern Office Web Add-ins using Office.js, JavaScript / TypeScript, HTML, and CSS.
- Work with Node.js for Office Web Add-in development and build tooling.
- Work with add-in manifests, command buttons, task panes, and Office.js APIs.
- Integrate Office Web Add-ins with backend APIs.
- Debug add-ins across Microsoft 365, Outlook Web, and supported Office clients.

API and Integration Development

- Integrate add-ins with backend APIs and enterprise services.
- Implement REST API communication, authentication, authorization, and token handling.
- Handle API errors, retries, timeouts, and user-friendly error messages.
- Work with Microsoft Graph API where required.
- Ensure secure handling of tokens, user data, document metadata, and sensitive information.

Performance and Code Quality

- Optimize add-ins for startup time, responsiveness, and memory usage.
- Ensure add-ins do not impact Office application performance.
- Follow secure coding practices.
- Implement proper logging,



exception handling, and error diagnostics.
- Troubleshoot performance issues, memory leaks, and application stability issues.

Mandatory Skills

- Strong hands-on experience in C# and .NET.
- Experience in Microsoft Office Add-ins development.
- Experience with VSTO, COM Add-ins, Office Interop APIs, and Office Object Model.
- Good understanding of Microsoft Word, Excel, PowerPoint, and Outlook integration.
- Experience with Ribbon customization, task panes, Office events, and Office UI integration.
- Strong debugging and troubleshooting skills in Windows desktop application development.
- Good understanding of REST APIs, authentication, authorization, and secure communication.
- Ability to write clean, secure, scalable, and maintainable code.

Good to Have Skills

- Experience with Node.js, JavaScript / TypeScript, HTML, CSS, and Office.js.
- Experience in developing Office Web Add-ins for Microsoft 365 / Outlook Web.
- Experience with Microsoft Graph API.
- Experience with npm, webpack, Vite, or similar JavaScript build tools.
- Knowledge of Windows registry, certificates, Office Trust Center settings, and Office add-in load behavior.
- Experience with SQL Server, MySQL, PostgreSQL, or similar databases.
- Experience in cybersecurity, data protection, compliance, DLP, classification, or enterprise security products will be an added advantage.

Qualification

- B.E. / B.Tech / MCA / M.Tech in Computer Science, Information Technology, or related field.
- 3-6 years of software development experience.
- Minimum 2+ years of hands-on experience in C# / .NET development.
- Prior experience in Microsoft Office Add-ins, VSTO, COM Add-ins, Office.js, or enterprise desktop application development will be preferred.

📌 Office Add-ins Developer (India)
🏢 SISA
📍 India