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Pretty-Print JSON

Last updated: 26 September 2026

Pretty-printing means rewriting JSON with indentation and line breaks so a person can read it. Here is a box that does it in your browser, followed by the one-liners for terminals, editors and code.

What changes and what does not

Pretty-printing inserts whitespace between tokens: line breaks, indentation, and a space after each : and ,. Nothing else moves. Property order is preserved, string contents are untouched — including spaces inside them — and no numbers are rounded. Parse the file before and after and you get identical data, which is why minifying and pretty-printing are reversible operations on the same document.

Pretty-print JSON in a terminal

For files too large or too sensitive to paste into a browser:

• jq '.' config.json — the standard choice; . is the identity filter, so all the work is the pretty output.
• python3 -m json.tool config.json — ships with Python; add --indent 4 to change the width and --sort-keys to reorder them.
• node -e 'const f=require("fs");f.writeFileSync(1,JSON.stringify(JSON.parse(f.readFileSync(process.argv[1],"utf8")),null,2))' config.json — the same parser your application uses.

All three read stdin, so a live API response works without saving it first:

• curl -s https://api.example.com/status | jq .
• curl -s https://api.example.com/status | python3 -m json.tool

When you only want one branch of a big document, filter instead of scrolling: jq '.limits' config.json prints just that object, and jq -r '.regions[]' lists array items one per line.

Pretty-print inside your code

• JavaScript — JSON.stringify(value, null, 2). The third argument is the indent; omitting it gives compact output.
• Python — json.dumps(data, indent=2, ensure_ascii=False). Without ensure_ascii=False every non-ASCII character becomes a \uXXXX escape, which is valid but unreadable.
• Go — json.MarshalIndent(v, "", " "); json.Marshal alone is always compact.
• Rust — serde_json::to_string_pretty(&value)?.
• Java — new GsonBuilder().setPrettyPrinting().create().toJson(value).
• PHP — json_encode($value, JSON_PRETTY_PRINT).

In an editor

VS Code: paste, then Shift+Option+F on macOS or Shift+Alt+F on Windows and Linux to format the document; set "editor.tabSize": 2 to control the width. IntelliJ and WebStorm: Cmd+Option+L (Ctrl+Alt+L) to reformat. Sublime Text needs a package such as Pretty JSON. Most editors will refuse to format a file with a syntax error, so fix the error first — the validator reports the line and column.

When you should not pretty-print

Pretty output is bigger — often 20–45% bigger, and more for deeply nested data — so sending it over the network costs real bytes on every request. Anything a machine consumes should stay compact: API responses, bundled assets, localStorage values. Minify those instead, and keep indentation for files a human reads and reviews in a diff.

Two other cases worth knowing: a several-megabyte document will make a browser tab or editor crawl, so slice it with jq rather than opening it whole; and if the goal is comparing two payloads, sort the keys first — the formatter's recursive key sort puts two files in the same order so a diff shows only real changes.

Frequently Asked Questions