Paste any valid JSON and get back the smallest possible version, no line breaks, no indentation. Runs entirely in your browser, no signup.
JSON minifier
Paste any valid JSON, however it's currently formatted, spread across lines, inconsistently indented, already partly compact, and this app parses it and returns the smallest valid representation of the exact same data: no line breaks, no indentation, no unnecessary spaces.
It's local. Parsing and minifying run in your browser, not on a server, so nothing you paste is uploaded and there's no limit on how much JSON you minify.
The underlying fact
JSON's grammar treats spaces, tabs and line breaks between its structural characters, braces, brackets, colons, commas, as entirely optional. '{"a":1}' and the same object spread across five indented lines describe exactly the same data to anything parsing it. The formatting exists purely for whoever's reading the file, never for the machine consuming it.
That's exactly what minifying takes advantage of: since none of that whitespace changes the meaning, removing every byte of it produces a file functionally identical to the original but smaller.
Workflow
Nothing to configure, nothing to install.
Why it matters
The saving is pure byte count, nothing about the data's structure or meaning changes. For a payload embedded in a URL query parameter, a value stuffed into an environment variable, a script tag's inline data, or a '.min.json' asset shipped to every visitor, every removed byte is one less byte to transmit and parse.
For a small, one-off object the difference is trivial. For a large config file, a sizeable API response used as a fixture, or an asset served to thousands of page loads, the removed whitespace adds up to a real, if modest, reduction in transfer size.
A side effect worth knowing
To minify anything, this app first has to parse it, which means anything that isn't syntactically valid JSON, a trailing comma, an unquoted key, a comment, gets rejected outright rather than silently mangled. That makes this app a quick validity check as a side effect, even when saving bytes wasn't the point of pasting something in.
A common reason for rejection is pasting JSON5 or JSONC, formats that allow comments and trailing commas and look almost identical to plain JSON. Standard JSON supports neither, so text copied from a config written in one of those relaxed formats fails here until the comments and trailing commas are removed.
Straight answer
No, worth being direct about that. This app confirms what you pasted follows JSON's syntax rules, correctly matched braces and brackets, properly quoted keys, no trailing commas. It has no idea whether the values inside are the right values, whether a required field's missing, or whether a number should've been a string.
Syntactic validity and correctness are two different things. Minifying, or its counterpart, pretty-printing, only ever addresses the first.
Who it's for
Developers use it to shrink a config value that has to fit into a single environment variable, a URL parameter or a command-line argument. Front-end engineers use it to compact a small JSON asset before it ships to every page load, when a build tool's own minification step isn't available.
Anyone preparing a JSON payload for a single-line log entry, a database column that doesn't handle line breaks well, or a chat message with a length limit uses it to compress the JSON to one clean line without touching any of the data inside.
Paste your JSON above and press Minify. The compact, single-line version appears in the output box, ready to copy.
Yes, no signup, no paste limit, no run limit. It runs entirely in your browser.
No, parsing and minifying happen on your own device. Nothing is transmitted or stored.
No, only whitespace between structural characters is removed. Every key, value and array item stays exactly as it was.
The text doesn't follow JSON's syntax rules, most often a trailing comma, an unquoted key, or a comment, none of which standard JSON allows.
No, standard JSON doesn't support comments or trailing commas, so text in those relaxed formats needs those removed first.
No, keys stay in the exact order they appeared. Minifying only removes whitespace, it doesn't reorganise anything.
Yes, no length cap and no run limit. Very large files depend on your own device's memory.
Yes, the layout stacks on narrow screens.
This removes all unnecessary whitespace to make the file as small as possible. The prettifier does the opposite, adding indentation and line breaks for readability.
No, it only confirms the syntax parses. It can't tell if a value is wrong, a field's missing, or a number should've been a string.
No, the result describes exactly the same data as the input. Minifying is lossless as far as the data itself is concerned.
Yes, any valid JSON value, an object, an array, a string, a number, minifies the same way.
Not yet, paste, minify, copy for now.
It can't, since standard JSON doesn't support comments at all, so a file containing them fails to parse rather than having them stripped.
A manual find-and-replace can break string values that legitimately contain a line break or extra spaces. This app parses the structure first, so it never touches a string value incorrectly.
Yes, any valid JSON string content passes through unchanged, since minifying only affects whitespace between structural characters.
Yes, nothing is transmitted anywhere. Processing happens locally in your browser.
It depends entirely on how much whitespace the original had. A heavily indented, deeply nested file shrinks more than one that was already fairly compact.
Yes, minified JSON is exactly as valid as pretty-printed JSON to any parser. The formatting change has no effect on how it's consumed.