← Home AlveaHubs — free, no sign-up, works offline

JSON Formatter, Validator & Minifier

Format raw or minified JSON into readable indented output, validate it, or minify it into a compact single line. Everything runs locally in your browser — no JSON data is ever sent to a server.

About this tool

This tool formats raw or minified JSON into human-readable indented output, or minifies it into a compact single line. Validation happens at the same time — if the input is not valid JSON, an error message is shown. You can choose between 2-space, 4-space, or tab indentation, and optionally sort all object keys alphabetically. Everything runs in your browser using JavaScript's built-in JSON.parse and JSON.stringify.

How to use

  1. Paste your JSON into the input field.
  2. Choose an indent size (2 spaces, 4 spaces, or tab) and optionally enable key sorting.
  3. Click Format for readable output, or Minify for a compact single-line version.
  4. Copy the result from the output field.

When to use this tool

  • Debugging an API response by making it readable before inspecting its structure.
  • Minifying a JSON config file to reduce its size before deploying.
  • Checking whether a JSON string is valid before using it in code.
  • Sorting keys to make two JSON objects easier to compare side by side.

Frequently asked questions

Does this tool fix broken JSON?

No. It validates and formats valid JSON only. Syntax errors show an error message.

What does "Sort keys alphabetically" do?

Reorders all object keys into alphabetical order at every level of nesting, making large structures easier to compare or read.

What is the difference between Format and Minify?

Format adds indentation and line breaks for readability. Minify removes all whitespace for a smaller file size. Both validate the input first.

Is there a size limit?

No enforced limit. Very large files may slow the browser tab as everything runs locally.

Is my JSON sent to a server?

No. All formatting runs in your browser using JSON.parse and JSON.stringify. Nothing is transmitted.

Does this work offline?

Yes. Once the page has loaded, all processing runs locally.

Which indent style should I choose?

2 spaces is most common for JSON. 4 spaces matches Python conventions. Tabs suit some codebases — check your project's style guide.

Is this tool free?

Yes, completely free with no sign-up required and no usage limits.

Everything is processed locally in your browser — the JSON is never sent to a server.