What does a JSON formatter do?

It takes JSON, which is often sent as one long line, and rewrites it with line breaks and indentation so people can read it. It also checks that the JSON is valid and tells you where it is not.

How do I find the error in my JSON?

Paste it in the left box. If it is not valid, the message under the box says what is wrong and, for most errors, on which line and column. Select Go to error to put the cursor there. Common causes are a trailing comma, a missing quote, or single quotes instead of double quotes.

What is the difference between beautify and minify?

Beautify adds line breaks and indentation for people to read. Minify removes them so the JSON takes as little space as possible, which is what you want in a request body, an environment variable or a URL. Both keep the same data.

Is my JSON uploaded anywhere?

No. The formatter runs entirely in your browser and nothing is sent to the server, so it is safe to use with API responses and customer data.

Does it accept comments or trailing commas?

No. Comments, trailing commas, single quotes and unquoted keys are not part of standard JSON, so they are reported as errors. Remove them and the JSON will format.

Will formatting change my data?

No. Keys, values and their order stay the same unless you turn on Sort keys, and numbers are kept exactly as written. If a key appears twice in the same object, only the last one is kept, as with any JSON parser.

JSON formatter and validator

Paste JSON to beautify, validate or minify it as you type.

Valid JSON

Beautify

Minify

Indentation

2 spaces

4 spaces

Tab

Sort keys

JSON

Formatted JSON

Readable JSON in one paste

Fast Note's JSON formatter turns a wall of JSON into neatly indented text, checks that it is valid, and points to the line and column of any error. Paste an API response, a config file or a log entry on the left and the formatted result appears on the right. Nothing is uploaded.

Beautify or minify

Turn compact JSON into neatly indented text you can read, or strip every space and line break to make it as small as possible for a request body or a config value.

Errors shown by line and column

When the JSON is not valid, you see what is wrong and where. Select Go to error to jump to the spot in your text, such as a missing comma or an extra bracket.

Indentation and sorted keys

Indent with 2 spaces, 4 spaces or tabs, and sort object keys alphabetically to make two JSON files easier to compare.

Numbers kept exactly as written

Long IDs like 12345678901234567890 and values like 1.50 stay exactly as they are, instead of being rounded or rewritten. Older browsers warn you if a number had to be rounded.

Runs in your browser

Formatting happens on your device. Nothing you paste is sent to Fast Note, so you can safely format API responses, logs and config files.

Results as you type

There is no button to press. The output updates while you type or paste, and Copy puts it on your clipboard in one click. No account needed.

Comparing two JSON files? Format both with Sort keys on, then paste them into the diff checker.

Your notes

Saved diffs