Format, Validate, and Diff JSON API Responses
Prettify minified API responses and config files for easy reading, catch syntax errors with instant validation, and visually compare two JSON payloads with the diff tool — no installation, no setup.
2 differences detected instantly
API response changes spotted instantly with text diff and pretty-print
Why This Takes Longer Than It Should
When an API response isn't what you expected, step one is making the minified JSON readable. Most developers paste it into whatever formatter comes up in search — and that JSON routinely contains an access token, internal user IDs, and production endpoints. A debugging convenience turns into shipping live credentials to someone else's server.
What's Actually At Risk Here
- ✓API responses carry tokens and session IDs. Pasting one into an external site to pretty-print it is a direct credential leak.
- ✓Formatting, validating, and diffing all run in the browser, so you can keep working with production payloads.
- ✓It works offline, which means it also works inside a network-isolated staging environment.
2 Steps to Get It Done
Click any tool name below to go directly to that tool.
- 1JSON Formatter
Prettify minified JSON with indentation for readability. Syntax errors are flagged immediately during formatting
- 2Text Diff
Compare two JSON texts side-by-side and visually identify added, changed, and removed fields
Where People Get Tripped Up
These catch people out even when the steps are followed correctly. Skimming them first saves a redo.
- Readable isn't the same as shareable. Mask tokens before pasting into a log or a ticket.
- Very large payloads (tens of MB) eat browser memory. Extract the relevant portion first.
- Diffs are sensitive to key order. Format both sides first to cut out meaningless differences.
Frequently Asked Questions
- Does it validate against a JSON schema?
- Only JSON syntax validation is currently supported. Schema validation (types, required fields) is not available.
- Does it work with large JSON files?
- Processing happens in your browser, so very large files (tens of MB or more) may be slow. Typical API responses and config files (a few MB or less) work without issue.
Related How-To Guides
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