What is a JSON file?
JSON — structured data
Use the format JSON
A concrete example
Prepare a CSV from a JSON list of items with the same fields.
Useful checks
Nested objects do not correspond directly to the columns of a table. Check numbers, null values, and lists.
Choose a conversion
Keep the original and open the result in the software or on the device that will need to use it.
Your questions about this format
Why does my JSON change structure when converted to CSV?
CSV represents a table of rows and columns. JSON can contain objects and nested lists that do not transpose directly. Convert a copy, check how the fields are represented, and keep the JSON if your usage requires retaining its entire structure.
How can one avoid losing the leading zeros in identifiers?
When opening the CSV in a spreadsheet, import the identifier columns as text. Automatic opening can turn 00123 into 123. Also check the dates and decimal separators before re-saving.
Can I convert a file containing secrets?
Remove passwords, API keys, and other secrets before sending a sample to the service or support. File processing is done online. For data that must not leave your device, use a suitable local tool.
Why aren't all outputs offered?
Formats are not interchangeable in all cases. ConvertLab displays the conversions from its catalog; renaming an extension does not change the content. Specialized outputs like certain XML exports or spreadsheets are identified as NoLimit.
What is it?
JSON is the data-interchange format of the web. It doesn't describe a document but a structure: name/value pairs, lists, nested objects. It's what flows between an application and its server, millions of times a second across the globe.
Its syntax is minimal — braces, brackets, quotation marks — and stays readable by a human, which is unusual for a machine format.
History & origin
Douglas Crockford formalized JSON in the early 2000s, simply by codifying the way the JavaScript language declares its objects. He didn't invent anything: he named and documented something that already existed.
That simplicity won out over XML, dominant at the time: within a few years, nearly every web interface had switched to JSON.
Why it is useful
Lightweight, readable, universal: every programming language can read and write it without needing some obscure library.
It handles nested structures naturally, whereas CSV is hopelessly limited to a flat table.
Limits & drawbacks
No comments are allowed — a gap regularly cursed by those who use it for configuration files.
No date types, no comments, and an unforgiving syntax: one stray comma and the whole file becomes invalid.
Practical tips
To turn JSON data into a table you can work with in a spreadsheet, convert it to CSV — provided the structure is flat. Nested objects don't fit into columns.
For a configuration file that humans will be editing, YAML or TOML are more pleasant to work with: they allow comments.
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Convert a JSON