What it is
The CSV and JSON Converter goes both ways: paste or upload a CSV and get JSON, or paste JSON and get a CSV back. It is the small chore that sits between a spreadsheet export and an API, and it comes up constantly.
The two directions
CSV to JSON is what you reach for when a client, a colleague or an export gives you a table and your code needs objects. The first row becomes the keys; every row after it becomes an object.
JSON to CSV is the opposite trip, and it is the one people underestimate. JSON allows nesting, and a spreadsheet does not: an array of flat objects converts cleanly, but an object containing another object has to be flattened first, usually by joining the names with a dot. Records that do not all share the same keys end up with empty cells wherever a key was missing.
How to use it
- Paste your data or add a file.
- Pick the direction, CSV to JSON or JSON to CSV.
- Copy or download the result.
Things that trip people up
The separator. Not every CSV uses a comma. Semicolons are common wherever the decimal separator is a comma, and a mismatch produces one giant column.
Quoting. A value that itself contains the separator has to be wrapped in quotes, and a quote inside a quoted value has to be doubled. Malformed quoting is the most common reason a CSV parses into nonsense.
Type inference. A code like 007 read as a number becomes 7. If leading zeros matter, keep the column as text.
Nothing is uploaded
The whole conversion happens in your browser. Your data is never sent to a server, never stored and never seen by anyone else, which matters when you are converting an export full of real records.