Generate Excel (XLSX) Documents in C# Without Microsoft Office

Creating Excel files in C# without relying on Microsoft Office is now more accessible and efficient thanks to Openize.OpenXML-SDK for .NET —a modern, open-source API designed for spreadsheet generation and automation. Whether you’re building financial reports, exporting application data, or automating spreadsheet creation, this tool allows you to generate XLSX documents quickly and cleanly.

Openize.OpenXML-SDK for .NET eliminates the need for Excel installations or COM interop. Instead, it offers a fast, clean interface for developers aiming to automate Excel-based tasks using pure C#. Its lightweight design and intuitive syntax make it ideal for any .NET-based project where Excel output is required.

Let’s walk through how to use it for automatic Excel generation from scratch.

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Why Use Openize.OpenXML-SDK for .NET?

Using Openize.OpenXML-SDK means:

  • No dependency on Microsoft Excel or Office installations
  • No complex interop or XML structures
  • Rapid generation of Excel documents with styled content

This open-source library is a great fit for use cases like:

  • Financial and operational reports
  • Exporting data to spreadsheets from web or desktop apps
  • Inventory, payroll, and analytics spreadsheets

In this post, we’ll cover:

  • Creating an Excel Document in C#

Creating an Excel Document in C#

Once the package is installed, follow these steps to build a functional spreadsheet in C#:

  1. Initialize a Workbook: Create a new workbook instance in memory.
  2. Save the File: Export the workbook to .xlsx format on disk.

Here’s a practical example that shows how to build a simple spreadsheet with a styled header and data rows:

This example demonstrates:

  • Adding a worksheet
  • Saving the workbook locally

Benefits of Using Openize.OpenXML-SDK for .NET

This API is purpose-built for real-world Excel use cases and provides:

  • No Excel Needed – Works independently of Microsoft Excel or Office.
  • Performance-Focused – Built for speed, perfect for large or frequent document tasks.
  • Rich Formatting – Apply styles, alignments, font weights, and more.
  • Multi-Sheet Support – Add multiple worksheets with unique data sets per sheet.

Conclusion

With Openize.OpenXML-SDK for .NET, automating Excel document creation in C# becomes simple, efficient, and platform-independent. It’s perfect for developers looking to implement spreadsheet exports, reporting features, or dynamic XLSX creation in modern .NET applications—without ever touching Excel itself.

FAQs

Q: Can I create multiple worksheets using this API?
Yes, the library fully supports multiple worksheets in one workbook.

Q: Is Openize.OpenXML-SDK free to use?
Absolutely! It’s open-source and free for both commercial and personal projects.

Q: How does it compare with ClosedXML or EPPlus?
Openize.OpenXML-SDK offers a lightweight and streamlined alternative, focused on performance and minimalism, ideal for fast Excel generation.