Excel a JSON

In modern web development, data is almost always consumed via JSON (JavaScript Object Notation). However, much of the world's commercial data still resides in Microsoft Excel workbooks. An Excel to JSON Converter bridges this gap, transforming tabular spreadsheets into structured, machine-readable objects ready for APIs, web apps, or database seeding. This tool adheres to the RFC 8259 JSON Standard and support the OpenXML (.xlsx) structure.

The conversion engine performs a sophisticated mapping from 2D grids to hierarchical objects:

1. OpenXML Extraction: The tool dissects the .xlsx ZIP container, extracting the XML data that defines the workbook's structure and cell contents.
2. Row-to-Object Mapping: The first row of the selected worksheet is typically treated as the "Header." Each subsequent row is converted into a JSON object where the header names become the keys.
3. Data Type Inference: Unlike CSV, which is string-only, our JSON converter can intelligently detect and cast data types. Prices are converted to Numbers, checkboxes to Booleans, and timestamps to ISO Date Strings.
4. Nested Property Support: By using dot notation in headers (e.g., user.name), the engine can generate deeply nested JSON trees, perfect for seeding complex NoSQL databases like MongoDB.
5. Multi-Sheet Handling: The tool identifies all worksheets within the workbook, allowing you to choose whether to export a single sheet or an array of objects representing the entire workbook.

The History of Excel and JSON

Microsoft Excel was first released in 1985 and has defined the standard for business data management for decades. The modern .xlsx format was introduced in 2007, moving from a binary format to a more open, XML-based standard.

JSON was popularized in 2001 by Douglas Crockford. While Excel is superior for human analysis and visual reporting, JSON is the undisputed "lingua franca" of the Modern Web, allowing developers to directly consume data in their front-end frameworks like React, Vue, or Angular.

Technical Comparison: Excel vs. JSON

Understanding the relationship between these formats is key to building responsive, data-driven applications.

By converting Excel to JSON, you move the data from a static file into a dynamic format that can be instantly indexed, searched, and rendered in any Modern Browser.

Security Considerations: Macro Safety and Data Privacy

Handling enterprise spreadsheets carries significant security responsibilities:

• Script Neutralization: Excel files can contain malicious VBA Macros. Our converter is a "data-only" tool; it completely ignores and strips any embedded macros, ensuring your environment remains safe.
• Client-Side Transformation: To ensure maximum Privacy, the entire conversion happens locally within your browser's Web Worker. Sensitive corporate data and financial figures are never transmitted to our servers.
• Precision Preservation: We use high-fidelity numeric parsers to prevent "IEEE 754" rounding issues, ensuring that large numbers (like 64-bit ID fields) remain exact during the transition to JSON format.

How It's Tested

We validate our converter against the official Microsoft Open XML SDK samples.

1. The "Header Mapping" Test:
   • Input: A sheet where Row 1 is Id, Name, Active.
   • Expected: [{"Id": 1, "Name": "Test", "Active": true}]
2. The "Empty Cell" Handling:
   • Input: A row where a middle cell is empty.
   • Expected: The resulting JSON object will either omit the key or sets it to null, preventing data misalignment.
3. The "Date Conversion" Test:
   • Input: A cell with Excel date formatting.
   • Expected: Transformation into a valid ISO 8601 string.
4. The "Multi-Sheet" Export:
   • Input: A workbook with three sheets.
   • Expected: Successful generation of a nested JSON object containing all three datasets.

Technical specifications are available at the Microsoft Office Dev Center, the JSON.org, and the SheetJS Technical documentation.