Convert JSON to CSV and back again
Turn a JSON array into a spreadsheet-ready CSV, or convert a CSV back into structured JSON. Numbers and booleans are typed correctly on the way back.
How it works
Paste your data
A JSON array of objects, or CSV rows with a header.
Choose a direction
JSON to CSV, or CSV to JSON.
Pick a separator
Comma, semicolon, tab or pipe.
It is processed on your machine
This is the kind of content people are most nervous about pasting into a website. Here nothing is transmitted: your browser reads the input, the tool works on it in the tab, and the result is handed straight back. Close the tab and it is gone.
- Opened from your disk by your browser — not sent anywhere first.
- Held in the tab while the tool works, then dropped.
- Saved to your device by your browser, not by a link to a server.
- Closing the tab clears the working copy completely.
- No account, so nothing is ever attached to an identity.
- No tracking of what you worked on or what was inside the file.
There is no queue and no retention policy to read. Whatever you pasted is released the moment the tab closes. See how your data stays inside the tab for the full picture, or follow the DevTools check to verify your file never leaves.
What people use it for
Getting an API response into a spreadsheet
Convert the JSON array to CSV and it opens as rows and columns instead of a wall of text.
Checking something before you ship it
A quick pass in the browser is faster than wiring up a build step for a one-off job.
Working on a machine you do not control
Because nothing is transmitted, it is safe to use on a shared or locked-down computer.
Handling data you are not allowed to upload
Customer records, keys and internal names often may not leave the organisation at all. Here they do not.
Formats & limits
What this tool accepts, what it produces, and what it will never ask you for.
- Input
- JSON array or CSV rows
- Output
- CSV rows or a JSON array
- Maximum file size
- Set by your device, not by a plan
- Files per run
- Not applicable — nothing is uploaded
- Sign-up required
- None
- Watermark
- Never added
- Works offline
- Yes, once the page has loaded
- Supported browsers
- Any current Chrome, Edge, Firefox or Safari
When something goes wrong
Invalid input stops with a plain message that points at the exact problem, rather than a spinner that never finishes.
The content is not in the shape this tool expects. Check for a missing bracket or an extra character and try again.
Why not an online service
A hosted version of this tool means your input is transmitted to a server you have no relationship with. Removing that step removes the whole category of risk.
A typical upload site
This tool
Questions
What JSON shape does the converter expect?
An array of flat objects, such as a list of records where each one has the same kinds of fields. Every unique key found across the records becomes a column.
How are commas inside values handled?
Fields containing a separator, a quote or a line break are wrapped in double quotes and any internal quotes are doubled, which is the standard CSV escaping rule.
Are numbers converted back to numbers?
Yes. When converting CSV to JSON, values that look like numbers become numbers and true or false become booleans, so the resulting JSON is properly typed rather than all strings.
Does it work without an internet connection?
Yes, once the page has loaded. Nothing is fetched while you work, so a dropped connection does not interrupt a run.
Do I need an account or an email address?
No. There is nothing to sign up for, and nothing is ever attached to an identity because no file leaves your device.
Can I use the result commercially?
Yes. Nothing produced here carries a watermark or a licence restriction, and no account is attached to the output.