CSV to JSON Converter
Turn spreadsheet rows into JSON objects
To convert CSV to JSON, drop your CSV file above and click Convert to JSON. Fylo uses the first row as keys and turns every following row into a JSON object, keeping numbers as numbers and empty cells as null. The pretty-printed JSON is ready for APIs, apps and scripts — converted entirely in your browser.
Drop documents here
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How to convert CSV to JSON
Add CSV files
Drop .csv files with a header row.
Convert
Click Convert to JSON.
Use the JSON
Download the .json file for your app, API or database.
Output structure
The result is an array of objects, one per row: a CSV with the header name,city,score becomes [{"name": "Asha", "city": "Pune", "score": 87}, …]. Numbers become JSON numbers, TRUE/FALSE become booleans, and empty cells become null, so the data is ready to use without extra parsing.
Tips for clean JSON
Give every column a unique, simple header — those become your property names. Remove notes or totals rows below the data. If an ID column such as a phone number should stay text, keep in mind that purely numeric values are converted to numbers.
Using the JSON in code
The output is standard, pretty-printed JSON, so you can load it directly: fetch('people.json').then(r => r.json()) in JavaScript, json.load in Python or JSON.parse anywhere. Because numbers and booleans are typed, you can sort and filter without converting strings first. Keep the original CSV if you'll edit the data in a spreadsheet later.
Learn more: CSV format guide · JSON format guide
| Property | CSV | JSON |
|---|---|---|
| Structure | Flat table | Nested objects and arrays |
| Types | Text only | Numbers, booleans, null |
| Best for | Spreadsheets | APIs and code |
Frequently asked questions
Does the first row need to be headers?
Yes, the first row provides the property names.
How are empty cells handled?
They become null.
Can I convert JSON back to CSV?
Yes, with JSON to CSV.
Is there a size limit?
Only your device's memory; tens of thousands of rows are fine.
Can I get the JSON as one line?
The output is pretty-printed for readability; any JSON tool can minify it.
What about CSVs without headers?
The first row is always used as keys, so add a header row first.
Is the order of rows kept?
Yes, records appear in the same order as the CSV rows.
Are my files uploaded to a server?
No. CSV to JSON runs entirely in your browser — your files are processed on your own device and never sent anywhere. Once the page has loaded, it even keeps working if your connection drops.
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