How do I convert a large JSON file to CSV without losing data formatting?

I know it was hard to convert a large JSON file to CSV format without losing data formatting when you have a 500MB JSON file. Below, I mentioned a few methods that help you convert JSON files to CSV format.
Method 1: Using Excel to convert JSON files to CSV
Open Excel
Go to the Data tab → click Get Data → From File → From JSON.
Select your JSON file
Excel will open the Power Query Editor window.
You’ll see a column named “Record” or “List” — this means Excel detected nested JSON data.
Expand nested fields
Click the small expand icon (↔) next to each column header to open up nested records.
Keep expanding until all the nested fields (like contact. type, contact. value, etc.) show as normal columns.
Flatten arrays
If your JSON contains lists (like multiple contacts or tags), Power Query lets you expand them into separate rows using the same expand icon.
Load data into Excel
Once everything looks right, click Close & Load.
The data will appear in a new worksheet.
Save as CSV
Go to File → Save As → Browse → Save as type: CSV (Comma delimited).

The above method may help you to convert Excel, which can handle up to a few hundred thousand rows, but 500 MB JSON is likely too large — it may hang or crash. So, the best and safest method to complete the conversion of JSON files to CSV is to use a dedicated tool rather than using a risky online converter tool. You can use Softaken JSON Converter for converting JSON files to CSV format or any other formats (XML, SQL, TXT, YAML, and many others) securely.
Steps to Convert JSON files to CSV
1. Download and run the JSON file Converter
2. Browse and add JSON files
3. Take a complete preview of the added data
4. Choose CSV format from the file type
5. Select the output directory and click the convert button.
After completing the JSON to CSV conversion, you can easily access the CSV file in Excel.