About this tool
Choose a delimiter and whether the first row contains headers, then convert CSV to JSON or JSON to CSV. Inspect the table alongside the complete code. CSV fields remain strings, including leading zeros. Header mode requires unique, non-empty names and equal row widths. JSON input must be an array of flat objects or arrays; nested values are rejected. Missing properties and null become empty CSV cells.
Input is limited to 5 MiB of UTF-8 text, output to 20 MiB and JSON nesting to 128 levels. Large code, tree and table previews are limited to keep the page responsive; copy and download include the complete result. Processing runs locally in a cancellable background worker, including in the downloaded offline tool.
To keep processing responsive, JSON and CSV accept up to 100,000 values or cells. SQL accepts up to 4,000 tokens and 100 nested levels.
Editing the input or settings clears the previous result. Copy and download always use the latest completed conversion.
Your text and files stay on this device. Nothing is uploaded or saved by this tool.
Frequently asked questions
How do I use this tool?
Choose a delimiter and whether the first row contains headers, then convert CSV to JSON or JSON to CSV. Inspect the table alongside the complete code. CSV fields remain strings, including leading zeros. Header mode requires unique, non-empty names and equal row widths. JSON input must be an array of flat objects or arrays; nested values are rejected. Missing properties and null become empty CSV cells.
How does it handle my data?
CSV values stay strings. Use unique, non-empty headers. Nested JSON objects and arrays must be flattened before conversion. Your text and files stay on this device. Nothing is uploaded or saved by this tool.
Can I use large files or work offline?
Input is limited to 5 MiB of UTF-8 text, output to 20 MiB and JSON nesting to 128 levels. Large code, tree and table previews are limited to keep the page responsive; copy and download include the complete result. Processing runs locally in a cancellable background worker, including in the downloaded offline tool. To keep processing responsive, JSON and CSV accept up to 100,000 values or cells. SQL accepts up to 4,000 tokens and 100 nested levels.
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