PureTools
Paste JSON to format, minify, validate and explore it locally.
JSON Formatter
Format, validate, compress and explore JSON with precise error lines, interactive tree view and copy or download actions. Runs entirely in your browser.
Size0 B
Nodes0
Depth0
Keys0
Validation error
Line -, column -Formatted output
Tree view
Run the formatter to build the tree view.
How to use the JSON Formatter
Paste some JSON, import a local file, or load the sample. The tool checks it for errors first, then formats, compresses or builds a tree view from the content. Use it to review, clean up or inspect structured data before moving it into documents, tests or the Word Counter for plain-text length checks.
- Paste or import JSON in the input editor. File import accepts local JSON or text files up to 10 MB.
- Choose an output mode - Format for readable indentation, Minify for compact payloads, Validate for diagnostics, or Tree for structure-first inspection.
- Adjust options such as 2 spaces, 4 spaces, tabs and recursive key sorting.
- Read validation feedback. Invalid JSON shows the error message, estimated line and column, and nearby context.
- Use the tree filter to find a key, value or path inside nested objects and arrays.
- Copy or download output. Downloads are created with local Blob URLs and revoked after use.
Power feature: precise diagnostics plus paths
Many formatters simply say the content is invalid. This tool pinpoints the exact line and column where the error is, then shows the nearby content with a marker so you can fix missing commas, extra brackets or incorrectly formatted text quickly. When the JSON is valid, the tree view shows the full structure with paths like $.users[0].email, making it easy to locate and reference any specific field.
Standards and limits
The validator follows browser JSON.parse behavior and the strict JSON data model defined by ECMA-404. That means comments, trailing commas and single-quoted strings are rejected even when a JavaScript object literal would accept similar syntax. If you receive a JSON payload that arrives as a Base64-encoded string, common in JWTs, MIME attachments and some REST APIs, decode it first with the Base64 Encoder & Decoder before pasting it here. For visual CSS data, use the CSS Gradient Generator; for image metadata exported as JSON, use the EXIF Viewer.
Frequently asked questions
What does this JSON formatter do?
This tool formats, validates, compresses and explores JSON entirely in your browser. Paste JSON or import a local .json file, then choose whether you want readable indentation, compact output, sorted keys or a structural tree view. If the JSON is invalid, the tool shows the error message plus the exact line and column so you can fix the problem without searching through the entire content manually.
Is my JSON uploaded to a server?
No. All processing runs entirely in your browser and the interface stays responsive throughout. PureTools has no server for this tool and never receives the JSON you paste or import. Your content and settings are kept only for the current tab session and erased automatically when you close the tab. Your data is never used to train AI models or improve machine learning systems.
Why does JSON validation fail on trailing commas or comments?
JSON follows a strict format. It does not allow trailing commas after the last item, comments, text wrapped in single quotes, or certain special values. Those patterns may work in programming code or other configuration formats, but they are not valid JSON. This formatter strictly validates the standard JSON format so the output is accepted by any website, app or server that reads JSON.
What is the difference between formatting and minifying JSON?
Formatting adds line breaks and indentation so humans can read the structure quickly. It is useful for debugging API responses, reviewing configuration files and comparing nested objects. Minifying removes unnecessary whitespace while preserving the exact data, producing a smaller string for network payloads, logs or embedded examples. Both operations first validate the JSON, so invalid input will produce an error instead of a misleading output.
How does the JSON tree view help with debugging?
The tree view turns nested data into a scannable list of paths, types and previews. Instead of searching through a block of text manually, you can filter for a key or value and immediately see where it lives in the structure. The path format, such as $.user.profile.email or $.items[0].price, makes it easy to reference any specific field.
Can I sort object keys alphabetically?
Yes. Enable Sort keys before formatting or minifying to recursively order object keys alphabetically at every level. This is helpful when comparing two JSON files, reviewing generated configuration or keeping fixtures stable in version control. Sorting changes only the order of object properties, not the values themselves. Arrays keep their original order because array order is meaningful data and should not be changed by a formatter.
What file size can I import?
The importer accepts local JSON or text files up to 10 MB. This limit exists because reading a very large file creates a significant load in the browser memory. Very large files may still work when pasted, but the tool intentionally avoids promising unlimited size. For extremely large logs or data exports, use a desktop text editor or a command-line tool instead.
Can this formatter handle sensitive API payloads?
The tool is designed for private local use: no account, no upload, no server processing and no third-party API calls for your JSON. That makes it safer than pasting secrets into a remote formatter. Still, treat secrets carefully. Avoid downloading or sharing formatted output if it contains tokens, passwords, customer data or private keys, and close the tab when finished so sessionStorage is cleared automatically.