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JWT Inspector

Developer

Inspect and decode JWT tokens without signature verification to view payload and expiration.

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JWT

Two tokens that both decode into a similar-looking payload can still differ in one detail that actually matters, the header's algorithm field, HS256 versus RS256, especially when integrating against an unfamiliar auth provider where a mismatched signing algorithm causes a rejection that looks like an entirely different problem. This tool inspects and decodes a JWT without verifying its signature, surfacing the header's algorithm alongside the payload and expiration rather than only the claims.

See more about the JWT Inspector

Useful for confirming which signing algorithm an unfamiliar token actually uses before integrating with a new auth provider, diagnosing an algorithm mismatch error that looks unrelated to signing at first glance, or inspecting a token's full header and payload together during development without needing the actual signing secret.

Key features

  • Clean interface
  • Fast processing
  • No signup required
  • Works offline

Quick answers for JWT Inspector

Does it verify the token's signature?
No, it only decodes the header and payload and displays the signature segment as-is, it never checks the signature against a secret or public key.
How can I tell if a token is expired at a glance?
A badge next to the input reads "Not expired," "Expired," or "Not yet valid" based on the exp and nbf claims compared against the current time, or "No exp claim" if the token does not set one.
What if I paste something that is not three dot-separated parts?
It shows an error explaining that a JWT needs a header, payload, and signature separated by dots, rather than trying to guess at a partial token.