Convert XLSX to JSON Online Free

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Converts to JSON in your browser · first daily conversion free · no signup

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Extract data from Excel spreadsheets as structured JSON. Each row becomes a JSON object with column headers as keys. Perfect for APIs, databases, and web applications.

By ChangeThisFile Team · Last updated: March 2026

Quick Answer

ChangeThisFile converts your Excel spreadsheet to structured JSON directly in your browser using the SheetJS library. Headers become keys and each row becomes a JSON object, ready for APIs and databases. Your file stays on your device for complete privacy. Free, instant, no signup required.

First daily conversion free No signup required Files stay on your device Instant conversion Updated May 2026

XLSX vs JSON: Format Comparison

Key differences between the two formats

Feature	XLSX	JSON
Format type	Binary spreadsheet (ZIP of XML)	Plain text data format
Data access	Requires Excel or library	Native in all programming languages
Data types	Excel types (dates, formulas, numbers)	String, number, boolean, null
Structure	Rows, columns, multiple sheets	Nested objects and arrays
File size	Larger with formatting overhead	Compact, data only
API compatibility	Not directly usable	Universal standard for web APIs
Human editing	Spreadsheet application required	Any text editor

When to Convert

Common scenarios where this conversion is useful

API data preparation

Convert Excel data to JSON for sending to REST APIs. Each spreadsheet row becomes a JSON object ready for POST requests or batch operations.

Web application data loading

Load spreadsheet data into JavaScript applications. JSON is natively parsed by browsers, making it ideal for client-side data display and manipulation.

NoSQL database seeding

Import spreadsheet data into MongoDB, Firebase, or CouchDB. JSON maps directly to document database records.

Data migration and ETL

Convert Excel reports to JSON as the first step in data migration pipelines. JSON is easier to transform, filter, and validate programmatically.

Who Uses This Conversion

Tailored guidance for different workflows

Developers

Convert XLSX config files to JSON for compatibility with different tools or frameworks
Transform XLSX API responses to JSON for debugging, logging, or documentation

Validate the converted JSON output with a linter to catch any structural issues from the conversion

Watch for data type coercion (e.g., numbers becoming strings) when converting between XLSX and JSON

Data Analysts

Convert XLSX exports to JSON for importing into spreadsheet software, databases, or BI tools
Transform XLSX datasets to JSON for sharing with teammates who use different analysis tools

Check that column delimiters and quote escaping are handled correctly in the converted JSON file

Preview the first few rows of the JSON output to verify headers and data alignment

System Administrators

Convert XLSX configuration to JSON when migrating between infrastructure tools or platforms
Transform XLSX log exports to JSON for ingesting into monitoring or analysis systems

Back up the original XLSX config before converting, especially for production systems

Test the converted JSON in a staging environment before deploying to production

How to Convert XLSX to JSON

1

Upload your Excel file

Drag and drop your .xlsx file onto the converter, or click to browse. The first sheet in the workbook is converted.
2

Automatic conversion

Column headers become JSON object keys. Each data row becomes a JSON object. Numbers, dates, and text are typed appropriately.
3

Download the JSON result

Click Download to save your .json file. The output is an array of objects, pretty-printed with 2-space indentation.

Automate this conversion

Convert XLSX to JSON via API

Integrate this conversion into your pipeline with 3 lines of code. Free tier: 25 conversions/month.

The free converter above runs entirely in your browser — your file is never uploaded. This optional API is a separate server-side endpoint for automating conversions at scale.

curl -X POST https://changethisfile.com/v1/convert \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -F "file=@input.xlsx" \
  -F "target=json" \
  -o output.json --fail

const form = new FormData();
form.append('file', fileInput.files[0]);
form.append('target', 'json');

const res = await fetch('https://changethisfile.com/v1/convert', {
  method: 'POST',
  headers: { 'Authorization': 'Bearer YOUR_API_KEY' },
  body: form
});
const blob = await res.blob(); // your converted JSON file

Replace YOUR_API_KEY with your free key — no credit card needed.

Get a free API key

Frequently Asked Questions

How are column headers used?

The first row of your spreadsheet becomes the JSON property names (keys). Each subsequent row creates a JSON object with those keys and the row's values.

What about Excel formulas?

Formulas are resolved to their last computed values. The JSON output contains the calculated results, not the formula expressions.

How are Excel dates converted?

Excel dates are converted to their text representation based on the cell format. ISO 8601 format (YYYY-MM-DD) is used when the original format is ambiguous.

Which sheet is converted?

The first (leftmost) sheet in the workbook is converted. If you need a different sheet, rearrange the order in Excel before converting.

How are empty cells handled?

Empty cells are omitted from the JSON objects. Each object only contains keys for cells that have values.

Are number types preserved?

Yes. Numeric cells become JSON numbers, not strings. This includes integers and decimals. Cells formatted as text remain strings.

Can I convert files with thousands of rows?

Yes. The converter handles large spreadsheets. Performance depends on your device's memory, but files with hundreds of thousands of rows work well.

Do I need Excel installed?

No. The converter uses SheetJS to parse Excel files directly in the browser. No Office installation is needed.

Can I convert password-protected files?

No. Password-protected Excel files cannot be parsed in the browser. Remove the password in Excel before converting.

Is my spreadsheet data private?

Yes. The conversion runs entirely in your browser. No data is sent to any server. Safe for confidential business data.

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