JSON Minifier
Remove the whitespace that pretty-printing added, and see exactly how many bytes you saved. The output can optionally escape the characters that make JSON dangerous to embed in an HTML page, which is the difference between a response that works and a response that breaks a script tag.
Keeps the JSON valid while making it impossible for a string value to close a <script> tag or open an attribute.
How json minifier works
- Paste the JSONFormatted or minified, the result is the same.
- Choose whether to escapeOnly needed when the output is going into an HTML page.
- Compare the sizesFurtu shows the before and after byte counts and the percentage saved.
What you get
Strip every byte of formatting from a JSON document. Everything happens inside this page: the file is read by your browser, transformed in memory and handed straight back to you as a download. There is no upload queue, no waiting for a server, and nothing left behind when you close the tab.
Supported formats
This tool works on text you paste or type, so there is no file format to worry about. Nothing you type is sent anywhere.
Limitations, stated up front
- Only whitespace is removed. Property order, duplicate keys and number formatting are left exactly as parsed.
- Minified JSON is unpleasant to read and impossible to diff usefully. Keep a formatted copy somewhere.
Frequently asked questions
Is the saving real, or is it just whitespace?
Just whitespace — which is most of the difference. JSON has no comments, so there is nothing else to remove without changing the data. Furtu reports the byte count before and after so the figure is measured rather than estimated.
What does escaping < > and & do?
It rewrites them as the Unicode escapes <, > and &. The parsed value is identical, but a string containing a closing script tag can no longer close the surrounding tag. This matters when JSON is embedded in HTML, which is common in server-rendered pages and in analytics snippets.
Does it strip the newline at the end?
No. A trailing newline costs one byte and makes the file behave in terminals and editors, so Furtu keeps it and excludes it from the saving figure.
Can it minify a broken document?
No, and it will not try. A document that does not parse is a document whose meaning is unknown, so Furtu reports the error rather than handing back a plausible-looking fragment.
Is my JSON uploaded?
No. Minification happens in your browser, so a payload containing secrets or personal data is never transmitted.