Is my file uploaded when converting CSV to JSON?

No. The conversion runs entirely in your browser. The file never leaves your device, there is no server to upload to, and the page works offline once loaded.

Is CSV to JSON conversion free?

Yes, with no account, no watermark and no file limit per day. frogConvert is open source and there is no server cost to recover, because your device does the work.

How large a file can I convert?

Up to 2 GB for a single file, 500 MB total per batch, and 300 files at once. The practical limit is your device's memory, since everything is processed locally.

Convert CSV to JSON

Turns tabular rows into JSON objects, using the header row for keys.

Convert CSV to JSON →

Runs on: the built-in JSON converter, running in this tab
Steps: Direct, a single conversion
Input: .csv · text/csv
Output: .json · application/json
Uploads: None. The file never leaves your device.

What to expect

CSV has no types, so numbers and booleans arrive as strings unless inferred. Irregular rows can produce inconsistent objects.

Why convert CSV without uploading

Most online converters take your file, send it to their servers, convert it there and hand back a download link. That means your document sits on someone else's disk, subject to their retention policy and their breaches. It also means you cannot use them offline, and cannot use them at all for anything confidential.

frogConvert does the conversion in the page itself, with the built-in JSON converter. There is no upload step because there is no server. You can disconnect from the network and it still works.

About the formats

CSV

Comma-separated values: one table, one type, no formatting and no formulas. Its simplicity is the reason it is universal and the reason it loses everything a spreadsheet adds. More about CSV files.

JSON

The default interchange format for structured data on the web: objects, arrays, strings, numbers, booleans and null. No comments, no date type, no schema. More about JSON files.

Common questions

Is my file uploaded when converting CSV to JSON?: No. The conversion runs entirely in your browser. The file never leaves your device, there is no server to upload to, and the page works offline once loaded.
Is CSV to JSON conversion free?: Yes, with no account, no watermark and no file limit per day. frogConvert is open source and there is no server cost to recover, because your device does the work.
How large a file can I convert?: Up to 2 GB for a single file, 500 MB total per batch, and 300 files at once. The practical limit is your device's memory, since everything is processed locally.
What is lost converting CSV to JSON?: CSV has no types, so numbers and booleans arrive as strings unless inferred. Irregular rows can produce inconsistent objects.