Security
JWT Decoder
Decode JWT header and payload locally without verifying signatures.
About this jwt decoder
Inspect JWT headers and payloads during API debugging without uploading tokens to a server.
Mavis Tools is built for quick utility work: paste the input, get the result, and move on. The page is static-first for speed, and the interactive work happens in your browser. That makes it useful for drafts, calculations, debugging snippets, and repeat everyday tasks.
This tool is intentionally focused. It does one job clearly instead of asking for an account or hiding the result behind a long workflow. Bookmark it if you need a fast jwt decoder that works on desktop and mobile.
FAQ
Does it verify signatures?
No. It decodes only. Signature verification requires keys and is not included.
Is it safe for sensitive tokens?
The decoder runs locally, but avoid pasting production secrets unless you understand the risk.
What parts are decoded?
The header and payload JSON are decoded from Base64URL.