FAQ

Frequently Asked Questions

Practical answers for formatting, validating, comparing, and working with JSON safely.

What is FormatJSON?

FormatJSON is a client-side JSON formatter and editor. It can format (pretty print), minify, sort keys, generate JSONPath output, and compare two JSON inputs.

Is my JSON uploaded to a server?

The formatter and editor run in your browser. Your JSON is processed on your device. Pages may still load third‑party resources (for example ads and icons) like most websites.

How do I format (pretty print) JSON?

Paste JSON into the editor and click Format. If the JSON is valid, it will reformat with consistent indentation.

How do I minify JSON?

Click Minify to remove whitespace and line breaks. This is helpful when you want a compact payload for a request or storage.

What does “invalid JSON” usually mean?

Most errors are caused by one of these:

Can I format very large JSON?

Yes, but browser memory and performance are the limiting factors. If the page feels slow, try the mobile editor or split the JSON into smaller parts.

Why does “Paste Over” not show on my device?

Some browsers restrict clipboard access. If clipboard APIs aren’t available, the paste button is hidden.

What does “Sort” do?

It sorts object keys alphabetically (case-insensitive). Arrays are kept in their original order unless they contain sortable primitives.

What is JSONPath and why is it useful?

JSONPath is a way to refer to a location inside JSON (similar to XPath for XML). It’s useful for debugging APIs and extracting values from nested objects.

See examples in JSONPath examples.

How do I compare two JSON files?

Paste JSON into “JSON One” and “JSON Two”, then click Load Diff. The diff view highlights additions, removals, and changes.

See tips in Compare JSON guide.

Do you support JSON5 / relaxed JSON?

This tool focuses on standard JSON (RFC 8259). If your input includes comments, trailing commas, or single quotes, convert it to valid JSON first.

Can I format JSON offline?

Once the page assets are loaded, the formatter/editor logic runs locally. Offline behavior depends on your browser caching and whether third-party resources are required for the UI you’re using.

Where can I report a bug or request a feature?

Please contact support with a short repro example (sanitize any sensitive data).