APILens open source
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The JSON formatter that doesn't sell your eyeballs.

Format, search and diff JSON/XML, decode JWTs, and query with JSONPath — 100% in your browser. No ads, no tracking, no account, MIT-licensed.

JSON formatter JSON validator JWT decoder JSON diff JSONPath tester XML formatter JSON to CSV XML to JSON JSON to YAML JSON to TypeScript Base64 encode / decode Unix timestamp converter
Try it free Pro features
Input
Output
Formatted output appears here.

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JSONPath query

Extract exactly what you need: $.store.book[*].title

JSON diff

Compare two documents and see exactly what changed.

Large-file mode Pro

Free is capped at 20k nodes / ~2 MB. Pro raises it to 200k nodes / 20 MB.

Included with Pro.

Pricing

Free

$0
  • Format & minify JSON/XML
  • Tree view + search
  • One-click JWT decode
  • JSONPath query
  • JSON diff (two documents)
  • Up to 20k nodes / ~2 MB
No account. No tracking.

Pro lifetime

$19 one-time
  • Everything in Free
  • Large-file mode (200k nodes / 20 MB)
  • Lifetime license, one purchase
  • Funds this open-source project
License key delivered instantly after payment.

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Free online JSON formatter, JSON diff, JSONPath & JWT decoder

Is APILens really free?

Yes. The JSON/XML formatter and minifier, tree view, search, and JWT decoder are free with no account and no sign-up. The free tier handles documents up to 20,000 nodes or ~2 MB.

Does my JSON leave my browser?

No. All formatting, diffing, JSONPath querying and JWT decoding happens 100% client-side in your browser. Nothing is uploaded, logged, or tracked.

How do I diff two JSON documents?

Paste the original and the new JSON into the two diff boxes and click Diff. APILens lists every added, removed, and changed path. JSON diff and JSONPath query are free — try them on the dedicated JSON diff and JSONPath tester pages.

How do I decode a JWT?

Paste the token into the input and it's decoded instantly — header, payload and signature are shown in a readable tree. Decoding is local and never sends your token anywhere.

What is JSONPath?

JSONPath is a query language for extracting values from JSON documents, like XPath for XML. APILens supports .key, [n], [*], .. recursive descent and [?(filters)].

Is there a Chrome extension?

Yes — APILens ships as an open-source Chrome (MV3) extension too, plus this web app. Both are MIT-licensed on GitHub.