CSV ↔ JSON
Convert CSV to JSON and back, with control over delimiters,headers and formatting. All conversions run entirely in your browser.
CSV ↔ JSON tool interface
How to convert CSV to JSON and JSON to CSV
Choose conversion direction
Use the mode toggle at the top to choose CSV → JSON or JSON → CSV. The input label and file type restrictions update automatically based on your selection.
Paste or upload your data
Paste your CSV or JSON into the input editor, or click Upload file to load a .csv or .json file from your device. The tool shows line count and size so you can see how large the input is.
Adjust conversion settings
Choose the CSV delimiter (auto, comma, semicolon, tab, or pipe) and whether the first row contains headers. For CSV → JSON you can also enable pretty-print and set the number of indent spaces.
Validate the structure
The tool automatically validates your input and highlights common issues like inconsistent columns in CSV or invalid JSON syntax. Fix any reported errors before converting.
Convert and review the output
Click the Convert button. The output pane shows the converted JSON or CSV. You can copy the result to your clipboard, download it as a file, or use the Swap button to move the output back into the input for further conversions.
Download or reuse the result
When you’re happy with the result, click Download to save it as a .json or .csv file, or keep refining your data using Swap and Convert again as needed.
Frequently asked questions
Does this converter upload my CSV or JSON to any server?
No. All CSV and JSON conversions happen entirely inside your browser using PapaParse and JavaScript. Your files and text never leave your device, ensuring complete privacy.
Why do I get a CSV parsing error even if my file looks correct?
CSV errors usually occur when the delimiter is incorrect, when rows have inconsistent column counts, or when the CSV contains hidden characters. Try switching the delimiter from Auto Detect to Comma, Semicolon, Tab, or Pipe. Also make sure your CSV is UTF-8 encoded.
What types of JSON can be converted to CSV?
You can convert a JSON array of objects (e.g., `[ {name: 'Alice'}, {name: 'Bob'} ]`) or a single JSON object (which will be wrapped into a single-row CSV). JSON strings, numbers, and nested objects are not directly supported because CSV requires flat key-value rows.
What does the 'Pretty Print' option do when converting to JSON?
Pretty print formats the JSON output across multiple lines using the indentation you choose (2 spaces by default). This is helpful for readability and debugging. If disabled, the output becomes compact minified JSON.
How does the tool handle CSV headers?
If 'First row contains column names' is enabled, the tool treats the first row as headers when parsing CSV to JSON, and includes headers when exporting JSON to CSV. When disabled, the tool auto-generates column names like `Column 1`, `Column 2`, etc.
Why does nothing happen when I press Convert?
The Convert button only activates when there is valid input text. Make sure you paste your CSV/JSON or upload a file first. Also, check for errors—malformed JSON or invalid CSV structure will prevent conversion.
Can I upload a file instead of pasting text?
Yes. You can upload a `.csv` file in CSV → JSON mode or a `.json` file in JSON → CSV mode. The tool loads the file content directly into the editor, and you can edit it before converting.
What does the 'Use output as input' button do?
It instantly moves the converted result back to the input editor and clears the old output. This is useful when performing chained conversions, such as cleaning JSON formatting and then converting it back to CSV.
Why does the downloaded file use generic names like data.json or data.csv?
To keep things consistent and secure, the tool always uses a predictable filename for downloads. You can rename the file after saving it, or paste the output manually if you want full control.