What is a CSV file?
CSV — plain-text table
Use the format CSV
A concrete example
Prepare a JSON from a CSV export of products.
Useful checks
Check the separator, the quotation marks, and the encoding. Leading zeros of identifiers must not disappear.
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?
CSV strips a table down to its bare essentials: one line per record, values separated by commas. Nothing else. No colours, no formulas, no multiple sheets.
That bareness is its strength: virtually any piece of software, any programming language, any database can read a CSV file. It's the common language of data.
History & origin
The format has been in use since the 1970s, long before it was ever described in an official document — that only happened in 2005, and even then without any binding authority.
This lack of a firm standard explains all the headaches people run into with it: everyone implemented it their own way.
Why it is useful
Universal, tiny, readable as plain text, and processable by a script across millions of rows in seconds.
It can be imported into any spreadsheet program and any database.
Limits & drawbacks
The separator is a nightmare: French spreadsheet software uses a semicolon, because the comma is already used as the decimal separator. An English-style CSV opened in a French copy of Excel ends up crammed into a single column.
Add encoding issues — accented characters turning into gibberish — and values that contain a comma themselves, and you've got three-quarters of the world's data-import problems right there.
Practical tips
After converting, always check three things: the separator, the encoding — aim for UTF-8 — and the quotation marks around any values that contain the separator.
To preserve formulas and formatting, convert to XLSX instead. For hierarchical data, CSV is structurally the wrong tool — use JSON instead.
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