JWT Decoder
Developer ToolsDecode a JWT header and payload. Signature is not verified unless you ask.
{
"header": {
"alg": "none"
},
"payload": {
"sub": "1234",
"name": "Calnora"
}
}Calculated Result
Decoded
Formula: Base64URL header.payload
About this calculator
Paste an access token. You see the JSON header and payload. This tool does not prove the signature is valid unless you add a secret later — treat the claims as untrusted.
How It Works & Formula
FormulaSplit header.payload.signature and Base64URL-decode JSON
Split on dots. Base64URL-decode part 0 and part 1, then JSON.parse.