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JWT Decoder
x402
JWT Decoder is a paid API for AI agents from conclavex402p04.pythonanywhere.com, paid per call via x402, $0.005/call, status unknown (last checked 2026-10-14).
Decodes a JWT token, parsing its header and payload claims without verifying the signature.
Price / call$0.005
Success—
StatusUnknown
How this service works
Decode a JWT — parse header and payload claims without a key (no signature verification).
Output
Returns a JSON object with two top-level keys: 'header' (containing JWT header fields like alg and typ) and 'payload' (containing all claims encoded in the JWT body such as sub, iat, exp, and any custom claims). No signature verification is performed.
Example use cases
Debug failing auth token
“I'm getting a 401 and I want to see what's inside this JWT to figure out if the claims look right — can you decode it and show me the header and payload? Token: eyJhbGciOiJSUzI1NiIsInR5cCI6IkpXVCJ9.eyJzdWIiOiJ1c3IxMjMiLCJleHAiOjE3MjAwMDAwMDB9.signature”
Check token expiry before request
“Before I make this API call, can you parse this JWT and tell me what the exp and iat claims say? I need to know if it's already expired. Token: eyJhbGciOiJIUzI1NiJ9.eyJzdWIiOiJ1c2VyQGV4YW1wbGUuY29tIiwiaWF0IjoxNzAwMDAwMDAwLCJleHAiOjE3MDAwMDM2MDB9.sig”
Identify JWT signing algorithm
“What algorithm is this JWT using — can you decode the header and tell me? I need to know if it's RS256 or HS256 before I configure my verifier. Here's the token: eyJhbGciOiJSUzI1NiIsImtpZCI6ImtleS0xIn0.eyJzdWIiOiJhYmMifQ.sig”
Technical details
Endpoint
POSThttps://conclavex402p04.pythonanywhere.com/u/jwt?utm_source=zero.xyzWhen to prefer
Use this endpoint when you need to quickly inspect the contents of a JWT — its header fields (algorithm, key ID) and payload claims (subject, expiry, custom data) — without needing to verify its authenticity. Ideal for debugging, logging, or pre-flight inspection in agent pipelines where signature verification is handled elsewhere.
Side effects
- Malformed or non-base64 JWT input returns an error
- Missing or empty token body causes validation failure
- Token with too many or too few segments (not 3-part) may fail to parse
- Payment failure (402) if x402 payment is not included or insufficient
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| inputrequired | object | |
| output | object |
Output
Schema · Response
{
"type": "json",
"example": {
"header": {
"alg": "none"
},
"payload": {
"sub": "1"
}
}
}Tags
x402
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