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Unprice JWT Decode & Verify API
x402
Unprice JWT Decode & Verify API is a paid API for AI agents from volkov.evgeny.m2.fvds.ru, paid per call via x402, $0.001/call, status unknown (last checked 2026-10-13).
Decodes and verifies a JWT token, returning its header, payload, and verification status via a pay-per-request endpoint.
Price / call$0.001
Success—
StatusUnknown
How this service works
Tiny paid web services for agents. Pay per request with USDC on Base via x402, plus non-x402 Base USDC tx-hash checkouts for Merchant Feed Audit, Base USDC receipts, and recent wallet statements.
Output
Returns a JSON object containing the JWT's decoded header (including the algorithm field), the decoded payload (e.g. subject claim), and a boolean 'verified' field indicating whether the token's signature was successfully verified.
Example use cases
Debug a received API token
“I got this JWT back from a third-party API: eyJhbGciOiJub25lIn0.eyJzdWIiOiIxIn0. — can you decode it and tell me what's in the payload and whether it's verified?”
Check JWT algorithm used
“Can you inspect this JWT token and tell me what signing algorithm is in the header? Token: eyJhbGciOiJSUzI1NiIsInR5cCI6IkpXVCJ9.eyJ1c2VyIjoiYWJjIn0.signature”
Validate token before trusting it
“Before I accept this token from a user, can you decode and verify it for me? Here it is: eyJhbGciOiJub25lIn0.eyJzdWIiOiJ1c2VyMTIzIn0.”
Technical details
Endpoint
GEThttps://volkov.evgeny.m2.fvds.ru/pay/jwt?utm_source=zero.xyzWhen to prefer
Use this endpoint when you need a quick, lightweight, pay-per-call JWT decode and verification without setting up a local JWT library or managing signing keys. Ideal for agent workflows that occasionally need to inspect tokens on-the-fly without a dedicated auth service. Best suited for low-volume, ad-hoc token inspection rather than high-throughput verification pipelines.
Side effects
- Missing or malformed token query parameter returns an error or empty result
- Token is structurally invalid (not a valid base64-encoded JWT) — parse error returned
- Unverifiable signature returns verified: false rather than an error
- Payment not completed (x402 flow not satisfied) — 402 Payment Required response
- Network timeout or server unavailability
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| inputrequired | object | |
| output | object |
Output
Schema · Response
{
"type": "json",
"example": {
"header": {
"alg": "none"
},
"payload": {
"sub": "1"
},
"verified": false
}
}Tags
x402
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