JSON formatterFormatters

JSON formatter and validator. Pretty print, minify, find the error.

Paste JSON and get it indented with 2 spaces, 4 spaces or tabs, or minified to one line. If it is invalid, you get the line, the column and what went wrong, such as a trailing comma or single quotes.

Cost to you

Free

Runs in your browser. No signup, no API call, no limit per hour.

browser
runs in
none
API calls
none
account

Use it now

Use the JSON formatter and validator here

It runs in your browser. Nothing you type is sent anywhere, there is no signup and no limit.

Loading the tool.

Run it from your agent

Copy one prompt, give it to your agent.

Fill in the placeholder, paste it, and the agent runs the same job with current data on your looot account and shows the cost.

  • You give it: json text.
  • Billed per call, nothing while your agent is idle.
  • The agent shows the price before it calls.
Prompt: JSON formatter and validator
Use looot to run [endpoint or job] and show me the raw answer. 1. Set up https://looot.ai/skill.md. 2. Search the catalog for the endpoint and check its price before you call. 3. Run it once with [input]. 4. Pretty print the JSON answer with 2 spaces, list the top-level keys and say which fields came back empty.

Give this to your agent
Setup command
set up looot - https://looot.ai/skill.md

What comes back

What your agent gets from json formatter

Field names as the providers return them. The exact set varies by endpoint, and your agent reads it from the catalog.

  • formatted JSON
  • minified JSON
  • error line and column
  • key and value counts
  • duplicate keys

Use it for

What people do with json formatter

  • Read an API answer

    Turn a one-line response into something you can scan.

  • Find the broken comma

    Get the line and column of the error in a config file.

  • Minify a payload

    Strip whitespace before you paste JSON into a header or an env var.

  • Stable diffs

    Sort keys so two versions of a file compare line by line.

Set up once

Three steps. Your agent does the rest.

Keep going

More free tools

FAQ

Questions about json formatter

Paste it in the box. Valid JSON is pretty printed below as you type. Pick 2 spaces, 4 spaces, tabs or minify.

The page parses JSON the way the standard defines it and stops at the first problem. It shows the line, the column and a caret under the spot, with the reason, such as a trailing comma or a key in single quotes.

JavaScript object syntax allows things JSON does not: single quotes, keys without quotes, trailing commas and comments. JSON needs double quotes everywhere and no trailing commas.

No. Numbers are printed exactly as written, so an id like 9007199254740993 keeps every digit. JSON.parse in a browser would round it.

Yes. Turn on Sort keys A to Z. Arrays keep their order, since order matters in an array.

They are valid JSON syntax but most parsers keep only the last value. The page lists any duplicates it finds.

No. Formatting and validation run in your browser, so API keys and customer data in the JSON stay on your machine.
For agents
tool
JSON formatter and validator
category
Formatters
input
JSON text
output
formatted JSON, minified JSON, error line and column, key and value counts, duplicate keys
price
per call, read live from the catalog on the web page
web tool
runs in the visitor's browser, no API call, free and unlimited
schedule
on demand
setup
https://looot.ai/skill.md
llms.txt
https://looot.ai/llms.txt
updated
2026-10-14
markdown /free-tools/json-formatter.md

Run json formatter from your own agent.

Start your workspace, top up, and paste the prompt into the agent you already use. It runs the job with live data and shows the cost first.

Start your workspace See all free tools