Free JSON to CSV and CSV to JSON Converter
From API to spreadsheet and back again
JSON is how programs talk, and CSV is how spreadsheets talk. Sooner or later you need to move data from one to the other: an API response you want to sort in Excel, or a spreadsheet export that a developer needs as JSON. This converter does both directions in one place. It flattens nested data, handles quotes and commas inside values correctly, detects the delimiter, and lets you copy or download the result. Your data stays in your browser, which matters for customer lists and exports.
JSON to CSV, step by step
- Choose JSON to CSV.
- Paste an array of objects, or open a .json file. If your JSON is an object wrapping one list, such as a data field, the converter uses that list.
- Decide whether to flatten nested objects. With the option on, an address object with a city inside becomes a column called address.city.
- Choose the delimiter and whether to include a header row.
- Copy the CSV or download it.
CSV to JSON, step by step
- Choose CSV to JSON and paste your CSV, or open a .csv file.
- Leave the delimiter on automatic detection, or choose it yourself.
- Tick First row is the header to use the column names as keys.
- Decide on types: turn numbers, true, false and null into real JSON values, or keep every value as text.
- Choose pretty or compact output, then copy or download.
Decisions that change your result
Nested data
A spreadsheet is flat, so something has to give. Flattening with dot names keeps the structure readable. Arrays inside a record, such as a list of tags, are kept as JSON text in one cell, because a cell cannot hold a list.
Different keys in different records
The columns are the combined set of all keys. A record without a key gets an empty cell, so nothing is lost.
Empty values and null
A null in JSON becomes an empty cell. Going the other way, an empty cell becomes an empty string, or a null if you turn on type conversion for the literal word null.
Problems people hit with Excel
- Everything appears in one column. Some regions use a semicolon as the list separator. Choose the semicolon delimiter, or use Excel’s import wizard.
- Leading zeros vanish. A phone number like 01712 becomes 1712 when treated as a number. Turn off the type conversion in CSV to JSON, and format the column as text in the spreadsheet.
- Long numbers turn into scientific notation. Spreadsheets shorten numbers with many digits. Import such columns as text.
- Bengali or other non-Latin text looks garbled. Open the file with the import option, such as Data, From Text or CSV, and choose UTF-8 encoding instead of double-clicking it.
A small example of the flow
You export a customer list from an API as JSON, with name, email and a nested address. Convert it to CSV with flattening on, open it in a spreadsheet, sort and fix a few entries, then save as CSV again. Convert that back to JSON, keep the header row on, and you have updated data ready for your application. If emails appear twice in your list, remove duplicate rows with the remove duplicate lines tool before you import it.
Choosing a delimiter
Commas are the default, but they clash with text that contains commas, such as addresses, which is why fields are wrapped in quotes. Semicolons are common in regions that write decimal numbers with a comma. Tabs avoid most clashes and are good for pasting into spreadsheets. Pipes are rare in ordinary text, which makes them handy for data you will process with scripts. Pick whichever the next program expects.
Checking the result
After converting, look at the row and column counts shown under the result, then spot-check the first, middle and last records. If a column is empty everywhere, a key may have been misspelled in the source. If values shifted, a quote or delimiter inside a field may not have been wrapped correctly in the original.
A caution about CSV files from other people
Cells that start with an equals sign, plus, minus or at sign can be run as formulas when a CSV is opened in a spreadsheet, which has been used to trick people into running harmful commands. If you open files from sources you do not trust, be careful with cells like that. When you produce CSV for others from data you do not control, consider adding a leading apostrophe to such cells.
FAQ
Choose JSON to CSV, paste your JSON array and copy or download the result.
Yes. Nested objects are flattened into columns using dot notation, such as address.city.
Values containing the delimiter, quotes or line breaks are wrapped in quotes, and inner quotes are doubled, following the CSV standard.
Yes. If Excel shows everything in one column, use the semicolon delimiter.
No. The conversion runs in your browser.