Zahra Sandra Nasaka for Syncfusion, Inc.

Posted on Jan 20 • Originally published at syncfusion.com on Jan 19

What’s the Best Way to Import Excel and CSV Files into a React App?

#fileformats #documentprocessing #migrationguides #react

TL;DR: Importing Excel or CSV files into React can be challenging, especially if you want to keep formatting intact and avoid data loss. Manual parsing is slow, complex, and prone to errors. The Syncfusion React Spreadsheet component solves this problem with built‑in support for importing Excel and CSV files. It allows you to upload, open, and render files with just a few lines of code, delivering accurate data handling and an effortless user experience.

Importing Excel or CSV files into a React application sounds simple until formatting breaks, formulas disappear, or large files slow everything down. Many teams start with manual parsing or table-based rendering, only to realize they’re rebuilding spreadsheet behavior from scratch.

A dedicated React Spreadsheet component changes that equation. Instead of treating Excel and CSV files as raw data, you can open them as fully interactive spreadsheets with styles, formulas, and structure preserved.

In this article, we’ll look at how Syncfusion React Spreadsheet file import actually works, why server-side processing matters, and two practical ways to open Excel or CSV files in React without fragile parsing logic.

Key features for efficient React Spreadsheet file import

The Syncfusion React Spreadsheet offers several features that make file handling smooth and reliable:

Support for Excel ( .xlsx, .xls, .xlsm, .xlsb ) and CSV formats.
Ability to upload and open files directly in the React UI.
Interactive grid with formulas, styles, and formatting.
Easy integration with React workflows and optional server-side processing.

How file imports work in React Spreadsheet

The React Spreadsheet component utilizes server-side processing to reliably import Excel and CSV files, preserving formatting and data integrity. This is made possible through the Syncfusion.EJ2.Spreadsheet server library, available for both ASP.NET Core and ASP.NET MVC apps.

To understand how everything fits together, here’s a breakdown of the import workflow:

1. Upload

When a user selects a file, it is automatically sent to the server for processing. This ensures the browser doesn’t have to handle heavy parsing tasks.

2. Processing

On the server, the Spreadsheet library uses Syncfusion XlsIO to read and extract the file’s content.

It converts all data cells, styles, formulas, and formatting into a Spreadsheet‑compatible JSON workbook that the React component can interpret.

3. Render

Once processed, the JSON workbook is returned to the client. The React Spreadsheet component then renders the imported content directly in the browser with full fidelity.

Note: All processing happens in memory during the request cycle. No file data is stored on the server, ensuring both performance and security.

How to enable file import in your React app

Before enabling file import, make sure your Spreadsheet app is properly set up by following the getting started guide.

To activate file import functionality, you’ll need to configure a few key settings:

Ensure the allowOpen property is enabled (it’s set to true by default).
Set the openUrl property to your backend API endpoint.
If you’re hosting your own backend, refer to the local service setup guide for proper configuration.

With the basics in place, let’s explore two ways to import Excel or CSV files into the React Spreadsheet component.

Option 1: Import files using the Ribbon UI

The Syncfusion React Spreadsheet comes with a built-in Ribbon UI that provides an interface similar to Microsoft Excel. This makes it easy for users to navigate file operations using a familiar layout.

How it works

When the user selects File -> Open from the Ribbon:

The browser opens the system file explorer for file selection.
The selected file is uploaded to the server via the configured openUrl.
The server processes the file and returns a JSON workbook, which is rendered in the spreadsheet component.

Best for: Users who want a simple, Excel-like experience without custom upload controls.

Importing Excel or CSV files in React Spreadsheet

Option 2: Import files using the open method

If your app needs custom workflows, such as integrating with custom UI elements or automating imports, you can use the open method.

Workflow

Use the Syncfusion React File Uploader to select an Excel or CSV file.
Once the upload completes, the File Uploader triggers the success event.
Inside this event, pass the raw file object to the Spreadsheet’s open method, which processes and uploads the file.

Best for: Custom UI, drag-and-drop, or button-triggered imports.

Refer to the following code example.

import * as React from 'react';
import { createRoot } from 'react-dom/client';
import { SpreadsheetComponent } from '@syncfusion/ej2-react-spreadsheet';
import { UploaderComponent } from '@syncfusion/ej2-react-inputs';

function App() {
  const spreadsheetRef = React.useRef(null);
  const uploaderRef = React.useRef(null);

  const asyncSettings = {
    saveUrl:
      'https://services.syncfusion.com/react/production/api/FileUploader/Save',
    removeUrl:
      'https://services.syncfusion.com/react/production/api/FileUploader/Remove',
  };

  const allowedExtensions = '.xlsx, .xls, .csv';

  const onSuccess = (args) => {
    if (args.operation == 'upload')
      spreadsheetRef.current.open({ file: args.file.rawFile });
  };

  return (
    <div>
      <UploaderComponent
        ref={uploaderRef}
        asyncSettings={asyncSettings}
        success={onSuccess}
        allowedExtensions={allowedExtensions}
      ></UploaderComponent>
      <SpreadsheetComponent
        ref={spreadsheetRef}
        openUrl="https://services.syncfusion.com/react/production/api/spreadsheet/open"
      />
    </div>
  );
}
export default App;

const root = createRoot(document.getElementById('root'));
root.render(<App />);

Alos, refer to the above code example on Stackblitz.

Importing a file using the open method in React Spreadsheet

For more detailed guidance on opening Excel files with the React File Uploader, consult the official user guide.

Other import options

The React Spreadsheet component supports multiple ways to open files, including local storage, external URLs, and Blob data. For advanced scenarios, refer to the resources below.

Events for file imports

The Syncfusion React Spreadsheet provides event hooks that allow you to customize and respond to file import operations. These events are useful for adding validations, modifying request behavior, or triggering UI updates:

The available events are:

beforeOpen: Triggered before the file is opened. We can use this to:

Modify request parameters before sending them to the server (e.g., add custom headers, such as authorization tokens).
Define parsing options that control how the Excel or CSV file is loaded.
Cancel the operation based on file type or content for security or validation purposes.

2. OpenComplete: Triggered after the file is successfully opened. This event is helpful for:
Displaying a success message or notification.
Enabling additional UI controls or features.
Performing updates in the spreadsheet, such as changing the active sheet, applying conditional formatting, or initializing custom logic.

For complete details on opening and saving files, check out the official guide.

Frequently Asked Questions

1. What is the Syncfusion React Spreadsheet component?

It’s a powerful UI component for React that allows you to view, edit, and manage spreadsheet data. It supports importing Excel ( .xlsx, .xls, .xlsm, .xlsb ) and CSV files directly into your React application. You can check out our documentation.

2. Why should I use Syncfusion React Spreadsheet for file imports?

It provides built-in support for Excel and CSV formats, preserves formatting and formulas, and offers easy integration with React workflows, reducing development time.

3. Which file formats are supported for import?

The component supports Microsoft Excel (.xlsx), Excel 97–2003 (.xls), Excel Macro-Enabled (.xlsm), Excel Binary (.xlsb), and CSV (.csv).

4. How does the file import process work?

Upload: The user selects a file, which is sent to the server. Processing: Server uses Syncfusion XlsIO library to convert the file into a Spreadsheet-compatible JSON. Render: JSON is returned to the client and displayed in the React Spreadsheet.

5. What are the ways to import files in React Spreadsheet?

Option 1: Use the Ribbon UI ( File → Open menu ) or Option 2: Use the open method with a custom file uploader for advanced workflows.

6. How do I enable file import in my project?

Set the allowOpen property to true. Configure openUrl with your backend service URL. You can set up your own backend using Syncfusion’s hosting guide.

7. Can I customize the file import process?

Yes, using event hooks like: beforeOpen: Modify request parameters or cancel the operation. openComplete: Trigger UI updates or apply custom logic after successful import.

8. What other import options are available?

You can open files from external URLs, Blob data, Base64 strings, or via custom fetch requests.

9. Can I import Excel files located in cloud storage into the Syncfusion React Spreadsheet?

Yes, you can import Excel or CSV files from cloud storage services like AWS S3, Google Cloud Storage, or Azure Blob Storage. Use your .NET backend service to fetch the file with credentials (e.g., via SDKs ), process it with Syncfusion Open API, and return it to the React client for display. This secures access and preserves data integrity.

10. Can I host the Syncfusion Spreadsheet server for file imports on cloud platforms like Azure App Service or AWS Lambda?

Yes, the backend (powered by Syncfusion XlsIO ) can be deployed to these platforms for scalability. For Azure App Service, deploy your ASP.NET Core service as an App Service; for AWS Lambda, use serverless functions to handle file processing. Create endpoints that accept file uploads and return JSON. This reduces overhead Lambda is ideal for on-demand imports. Syncfusion provides guides for scaling in hosted environments.

11. Is there a Docker image available for easy deployment of the Syncfusion Spreadsheet open server, and how do I use it?

Yes, Syncfusion offers a pre-built Docker image on Docker Hub based on an ASP.NET Core project, which requires no additional .NET code from your side. Pull it with **docker pull syncfusion/spreadsheet-server**, then run with docker run -d -p 6002:8080 --name spreadsheet-container syncfusion/spreadsheet-server. Configure your React app’s openUrl to point to this containerized server for file imports (e.g., for Excel/CSV processing). It’s lightweight, secure, and deployable on any platform supporting Docker, like Kubernetes or AWS ECS.

Conclusion

Thank you for reading! The Syncfusion React Spreadsheet makes importing Excel and CSV files into your React apps effortless and highly customizable. Whether you choose the intuitive Ribbon UI or the versatile open method, you can deliver a smooth, Excel-like experience for your users, complete with preserved formatting and styles.

If you’re a Syncfusion user, you can download the setup from the license and downloads page. Otherwise, you can download a free 30-day trial.

You can also contact us through our support forum, support portal, or feedback portal for queries. We are always happy to assist you!

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This article was originally published at Syncfusion.com.

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