onul.works

JWT Debugger

Paste a JWT to inspect its header, payload, claims, and expiration details without sending it to a server.

⌘ Runs in browser ◴ No data stored ⌁ Free
JWT input
JWT decoded result
JWT header and payload appear here. Signature verification is not performed.

How to use

  1. 1 Paste the encoded JWT you want to debug into the input field.
  2. 2 Check the decoded header and payload sections.
  3. 3 Copy the combined JSON result with both header and payload if needed.

Common use cases

  • Inspect JWT header algorithms with jwt debugger
  • Review payload claims
  • Check exp expiration claims

Frequently asked questions

What JWT format should I enter?

Enter a JWT in header.payload.signature form. The tool Base64URL-decodes the header and payload for jwt debugger style inspection.

What does the copy button copy?

The copy button copies one combined JSON result containing both the decoded header and payload. The page still shows each section separately for inspection.

Does it verify signatures or create tokens?

No. This tool is only for decoding a JWT to inspect its header and payload; it does not verify signatures or create tokens.

Related workflow

JWT DebuggerStart by decoding the JWT header and payload to inspect the claims it contains. → Base64 DecoderDecode Base64 fragments around the token separately when you need to compare the raw text. → Base64 EncoderTurn reviewed text into a Base64 representation when you need a reference encoded value.