JSON Viewer

Pretty‑print, validate, and explore JSON data in your browser

Start

{
  "hello": "world"
}

The JSON Viewer formats and validates JSON so it is easier to read and debug. Paste raw or minified JSON into the input, and the tool will parse it and produce a clean, indented output that highlights structural issues immediately. If the input is not valid JSON, you will see an actionable error instead of a crash.

Use this when you need to quickly understand nested objects and arrays, compare structures, or prepare payloads for APIs and configuration files. The viewer preserves key order, supports large inputs, and is optimized for fast, in‑browser formatting.

Key features

Fast pretty‑printing with consistent two‑space indentation
Instant validation with clear error messages for malformed JSON
Two‑panel layout for side‑by‑side input and formatted output
Copy, Clear, and Sample actions for quick workflows
Local persistence that restores your last input (no servers)
Keyboard and screen‑reader friendly controls

Common use cases

Debugging API responses from REST or GraphQL endpoints
Cleaning up configuration files such as package.json or app settings
Exploring nested data structures from logs and exports
Teaching or learning the JSON data model

Privacy & security: everything runs locally in your browser. Your JSON never leaves your device, which makes the tool safe for sensitive snippets. For text transformations you can also tryBase64 Decoder if your JSON is Base64‑encoded.

How to Use

Open the tool and focus the left “Input” panel.
Paste your JSON text (minified or formatted is fine).
If there is a syntax error, an error banner appears on the right. Fix the highlighted issue (missing comma, mismatched bracket, invalid quotes).
Once valid, the right panel shows pretty‑printed JSON with two‑space indentation.
Use “Copy Output” to copy the formatted JSON to your clipboard.
Use “Clear” to reset, or “Sample” to load an example payload.
Optionally tweak the input and repeat until it looks correct.

Tips

When in doubt, ensure all object keys are wrapped in double quotes.
Look for trailing commas; JSON does not allow them.
Use the “Sample” button to confirm that the tool works in your browser.
Working with Base64? Decode it first with Base64 Decoder and then paste the result here.

Troubleshooting

“Invalid JSON” → Ensure strings use double quotes and remove trailing commas.
Output is empty → The input may be blank or only whitespace; paste valid JSON.
Large input feels slow → Paste first, wait a moment; formatting runs efficiently but very large data can take a second.
Copied output looks minified → Make sure you copied from the right panel after it shows formatted text.

Example

Example 1: Minified → Formatted

Input:

{"name":"QuickTool","tools":[{"name":"JSON Viewer"}]}

Output:

{
  "name": "QuickTool",
  "tools": [
    {
      "name": "JSON Viewer"
    }
  ]
}

The structure is expanded with indentation, making arrays and objects easy to scan.

Example 2: Fix an error

Input (invalid – trailing comma):

{
  "ok": true,
}

Output: An error banner appears. Remove the trailing comma after true, then the output renders as:

{
  "ok": true
}

The viewer enforces strict JSON syntax to avoid surprises when sending data to APIs.

FAQ

Does this run locally and is it safe?

Yes. All parsing and formatting happen in your browser. No data is uploaded to any server, so it’s safe for everyday snippets.

Why is my output empty?

The input is either empty or invalid. Paste valid JSON and ensure you fix any syntax errors highlighted by the tool.

Can it handle large JSON files?

The viewer is optimized for speed and handles typical API payloads well. Very large multi‑MB files may take a moment to render.

What characters are allowed?

Only valid JSON syntax is allowed: double‑quoted strings, numbers, booleans, null, arrays, and objects. Comments and trailing commas are not permitted.

Does it sort keys?

No. Keys remain in their original order to avoid changing the meaning of the structure.

How do I convert from Base64‑encoded JSON?

First decode with Base64 Decoder, then paste the result into the viewer to format it.

Will it highlight differences between two objects?

This tool focuses on formatting and validation. For diffs, paste outputs into your preferred diff viewer.