Office Add-ins Developer

SISA; Bengaluru; Hybrid; INR 1,200,000 - 1,800,000; Full time

Job summary

SISA, Bengaluru, is seeking an experienced Office Add-ins Developer to design and implement robust add-ins for Word, Excel, PowerPoint, and Outlook using C#, .NET, VSTO, or COM Add-ins. Knowledge of Office.js and Node.js is a plus for modern Office Web add-ins.

The role requires 3-6 years of software development experience, strong debugging skills, and the ability to integrate with backend APIs while ensuring security and performance across Office platforms.

Qualifications

• 3-6 years of software development experience.
• 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 Word, Excel, PowerPoint, and Outlook integration.

Responsibilities

• Design and develop Microsoft Office add-ins using C#, .NET, VSTO, COM Add-ins, and Office Interop APIs.
• Build add-in features for 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.

Skills

C#

.NET

Office Add-ins Development

Node.js

JavaScript

TypeScript

Office.js

Education

B.E. / B.Tech / MCA / M.Tech in Computer Science or IT

Tools

VSTO

COM Add-ins

Office Interop APIs

Office Object Model

Job description

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 stable, 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.