JSON Formatter

About the JSON Formatter

Paste any JSON payload — an API response, a config blob, a log line — and get it pretty-printed with consistent indentation. Runs entirely client-side, so nothing you paste is ever uploaded.

How to use the JSON Formatter

1. Paste or type your JSON into the input box.
2. Click Format to pretty-print it, or Minify to strip whitespace.
3. Invalid JSON is flagged with the line and column of the syntax error.
4. Copy the result or download it as a .json file.

Step-by-step walkthrough with examples and the errors people hit: How to Format and Validate JSON Online.

Example

Minified input

{"user":{"id":1,"name":"Ada","active":true}}

{
  "user": {
    "id": 1,
    "name": "Ada",
    "active": true
  }
}

Common errors and how to fix them

More problems and fixes in the tutorial

Format, validate and minify in one place

Paste JSON and press Format to pretty-print it with two-space indentation and one key per line, or Minify to strip every byte of whitespace before it goes into a query string, an environment variable or a database column. Both operations start by parsing, so the same click validates the document: if it is not valid JSON you get the parser's message with the exact line and column instead of half-formatted output.

How the validation works

The formatter uses the JSON parser built into your browser, the same one that runs when a web application calls JSON.parse. That matters for two reasons: the error messages match what your own code will report, and there is no server involved, so a 40 MB export formats as quickly as your machine allows. Errors quote the position of the first problem; fix it, format again, and the next problem, if any, moves into view.

The usual culprits are a trailing comma after the last item, single quotes instead of double quotes, an unquoted key, a comment, or two documents pasted one after another. The tutorial linked above walks through each message and its fix.

When a JSON formatter earns its keep

API responses copied from a network tab or a curl call arrive minified. Structured logs embed JSON inside a text line. Configuration files such as package.json, tsconfig.json and composer.json get hand-edited until something breaks. In all three cases, formatting turns a blur into a structure you can read, and validation tells you whether the blur was ever valid at all. Formatting before you commit also produces clean diffs for reviewers.

Formatter, beautifier, viewer or validator?

The words are used interchangeably. A formatter or beautifier re-indents; a validator checks syntax and reports errors; a viewer adds a collapsible tree. This tool formats, validates and minifies. For comparing two documents structurally, use JSON Diff; for converting to YAML or CSV, the converters are one click away in the related tools.

Privacy and limits

Nothing you paste is uploaded. Parsing and formatting happen in the page, which is why the tool is safe for payloads that contain customer data or tokens. There is no server-side size limit; very large documents are limited only by your browser's memory. Keyboard: Ctrl+Enter formats, and Full screen gives the panes the whole window.

FAQ