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Duo Data Utilities – JWT Decoder
x402
Duo Data Utilities – JWT Decoder is a paid API for AI agents from api.duoleads.com, paid per call via x402, $0.05/call, status unknown (last checked 2026-10-02).
Decodes a JWT without signature verification, returning header, claims, payload, signature info, and computed time-claim analysis (expiry, not-before, remaining lifetime).
Price / call$0.05
Success—
StatusUnknown
How this service works
Decode a JSON Web Token without verifying it: returns the header, the claims, the signature length and algorithm, and a computed view of the time claims — whether exp has passed, whether nbf is in the future, and the remaining lifetime in seconds against a supplied or current instant. Reports structural problems such as a missing part, invalid base64url or an alg of none. It does not and cannot verify the signature; do not use it to decide trust.
Output
A JSON object containing the decoded JWT header (e.g. alg, typ, kid), full payload/claims (all registered and custom fields), number of parts, signature byte length, whether the structure is valid, any warnings (e.g. alg:none), and a computed time block showing whether exp has passed, whether nbf is still in the future, the age in seconds, and remaining lifetime — all evaluated against the supplied or current timestamp. The signature_verified field is always false since no verification is performed.
Example use cases
Debug an expired auth token
“This JWT keeps getting rejected by our API — can you decode it and tell me if it's expired, what the exp claim says, and how many seconds ago it expired? Token: eyJhbGciOiJSUzI1NiIsInR5cCI6IkpXVCJ9.eyJzdWIiOiJ1c2VyXzEyMyIsImV4cCI6MTY5MDAwMDAwMH0.abc123”
Inspect claims before trusting a token
“I got this JWT from a third-party service and I want to see exactly what's in the header and payload — show me all the claims, the algorithm, the kid, and whether the nbf or exp claims look valid: eyJhbGciOiJFUzI1NiIsInR5cCI6IkpXVCIsImtpZCI6ImtleS0xIn0.eyJpc3MiOiJodHRwczovL2V4YW1wbGUuY29tIiwic3ViIjoiYWJjIiwibmJmIjoyMDAwMDAwMDAwfQ.sig”
Evaluate token validity at a past timestamp
“Can you decode this JWT and check whether it would have been valid on January 1 2025 at midnight UTC? I want to know if it was expired or not-yet-valid at that specific moment. Token: eyJhbGciOiJIUzI1NiJ9.eyJleHAiOjE3MzU2ODk2MDB9.xyz”
Technical details
Endpoint
GEThttps://api.duoleads.com/v1/code/jwt?utm_source=zero.xyzWhen to prefer
Use this endpoint when you need to inspect the contents of a JWT token quickly — to read claims, check expiry timing, or debug token structure — without needing to verify the signature. It is ideal for debugging, logging, and introspection workflows where the signature is already trusted or irrelevant. Do not use it as a security gate or trust decision; it explicitly does not verify signatures.
Side effects
- Token is malformed or missing a part — returns structural error indicating which part is absent
- Invalid base64url encoding in header or payload — returns parse error
- Algorithm is 'none' — reported as a warning in the warnings array
- Token exceeds 8192 characters — rejected by input validation
- Invalid 'at' timestamp format (not RFC 3339 or epoch seconds) — returns validation error
- Network or service error — HTTP 5xx response
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| inputrequired | object | |
| output | object |
Output
Schema · Response
{
"type": "json",
"example": {
"ok": true,
"data": {
"alg": "HS256",
"kid": null,
"typ": "JWT",
"time": {
"expired": null,
"age_seconds": 274314578,
"evaluated_at": "2026-09-28T00:00:00Z",
"not_yet_valid": null,
"expires_in_seconds": null
},
"parts": 3,
"claims": {
"aud": null,
"exp": null,
"iat": 1516239022,
"iss": null,
"jti": null,
"nbf": null,
"sub": "1234567890"
},
"header": {
"alg": "HS256",
"typ": "JWT"
},
"reason": null,
"payload": {
"iat": 1516239022,
"sub": "1234567890",
"name": "John Doe"
},
"warnings": [],
"signature_bytes": 32,
"valid_structure": true,
"signature_verified": false
},
"meta": {
"price_usd": "0.05",
"disclaimer": "Factual output of a deterministic computation over public data. Provided as is, with no warranty of accuracy, completeness or availability. Not investment, financial, legal, tax, medical or any other professional advice, and not a recommendation. Verify before relying on it. Terms: https://api.duoleads.com/terms",
"request_id": "01K6B7Q4ZC8H3F2M9WXR5TYN0D",
"computed_at": "2026-09-28T12:00:00.000Z",
"deterministic": true
},
"route": "/v1/code/jwt",
"version": "1.0.0"
}
}Tags
x402
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