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JWT / Token Decoder
Decode JWT headers and payloads, inspect claims, and encode or decode Base64 locally in your browser.
Tokens and Base64 input stay in your browser. Nothing is sent to Vulnify.
Base64 Utility
What This Tool Checks
- JWT header and payload claims
- Signing algorithm and risky none values
- Base64 encode and decode utilities
Best For
Best for developers and security reviewers decoding tokens during API troubleshooting, OAuth integrations, or incident analysis.
What To Do Next
Treat decoded JWTs as sensitive data, verify signatures on the server, and reject tokens that use none or unexpected signing algorithms.
Related Resources
Does this tool verify JWT signatures?
No. It only decodes the header and payload for inspection. Signature verification must happen on your server with the correct secret or public key.
Is my token sent to Vulnify?
No. Decoding and Base64 utilities run entirely in your browser.