CSV to JSON
Open a CSV on this device, or paste it, and turn each row into a JSON object. Choose comma, semicolon, tab, pipe, or your own delimiter, and say whether row one is the keys.
Runs in your browser. Nothing is uploaded.
How it works
- Step 1: Paste your inputPaste directly into the editor, drop a file onto it, or use "Open file" to pick one from your device. Nothing is sent anywhere when you do.
- Step 2: ConvertAdjust the options if you need to, then run it. Results appear beside your input so you can compare the two.
- Step 3: Copy or download the outputCopy the result to your clipboard in one click, or save it as a file. You can also keep editing and re-run as many times as you like.
About this tool
What CSV to JSON writes
This address starts in CSV-to-JSON. A header switch decides whether row one becomes property names. Turn it off for a file that is only values and the keys are column_1, column_2, and the rest. The delimiter can be a comma, a semicolon, a tab, a pipe, or one character you type, which is the usual fix when a European spreadsheet used semicolons and a comma-only parser split every decimal.
Open a file from the device or paste. The read stays in the tab. Quoted cells that contain the delimiter stay one cell. The download is a JSON array. It is not an xlsx workbook; that job is CSV to Excel. Nested structure is not invented from flat cells. If you arrived with JSON, the swap control flips the boxes without changing this address, and JSON to CSV is the bookmark for the other way.
A cell's surrounding quote marks are removed, and a newline inside quotes is not preserved as one field. A short row still becomes an object: keys with no cell are empty strings. The saved name is converted.json. This page never opens an xlsx workbook.
- Runs in your browser. All processing happens locally in this tab using JavaScript.
- No uploads. Your data is never sent to a server. There is no server to send it to.
- Works offline. Once the page has loaded you can disconnect and keep working.
- Unlimited & free. No usage caps, no paywall, no file size tiers.
Start with your own data. Open a file
What happens to your data
The same questions a security review would ask, answered plainly.
- Read via
- Typed or pasted into the page
- Held in
- Your browser tab's memory for as long as it is open
- Stored
- Nothing. No cookies, no database, no server-side copy
- Transmitted
- Nothing leaves your device
- Retained after you close the tab
- Nothing
- Works offline
- Yes, once the page has loaded
Why use this tool
What you get here that a server-side alternative cannot offer.
Your data never leaves the tab
There is no upload step and no server to receive one. The page loads once, then all work on your data happens in local JavaScript.
No caps or paywalls
No daily limits, no per-file ceilings imposed by a server tier, no watermarks, and no account. The practical limit is your own device's memory.
Frequently asked questions
Is my CSV uploaded to a server?
No. Everything runs locally in your browser using JavaScript. Your data is never uploaded to a server, and nothing is stored or logged.
When does the first row become keys?
Leave the header switch on and row one is the property names. Switch it off and the keys are column_1, column_2, and so on, which is what you want for a file that is only values.
Can I point this at a semicolon export?
Yes. The delimiter list includes semicolon, tab, and pipe, plus a box for a character the list does not have. European spreadsheet exports usually want the semicolon.
How much data can I paste in?
There is no server-side cap. Very large inputs are limited only by your device's memory and will make the page feel slower, since the work happens on the main thread. In practice a few megabytes of text is comfortable.
Does it work offline?
Yes, once the page has loaded. The code that does the work is already in your browser at that point, so you can disconnect and keep using it. Reloading the page while offline needs the browser cache to still hold it.
Do I need to create an account?
No. There is no sign-up, no email, and no usage tracking tied to an identity. The tool works the first time you open it.