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Agent Dev Tools – JWT Decode
x402
Agent Dev Tools – JWT Decode is a paid API for AI agents from agent-dev-tools.frcompanycheck.workers.dev, paid per call via x402, $0.001/call, status unknown (last checked 2026-10-16).
Decodes a JWT token into its header, payload, and signature components, and reports expiry status — paid per call in USDC via x402.
Price / call$0.001
Success—
StatusUnknown
How this service works
Fast deterministic developer utilities for AI agents, paid per call in USDC via x402 (no account, no API key): UUID v4/v7, secure random numbers, dice, MD5/SHA/HMAC hashing, base64/hex/URL/HTML encoding, JSON validation/formatting, QR code SVG, password generation, JWT decoding and text statistics. Pure computation, nothing stored. Errors are never charged.
Output
Returns a JSON object containing the decoded JWT header (alg, typ), the full payload with all claims, the signature verification status (true/false), a null or boolean expired field, and human-readable ISO 8601 timestamps for time-based claims like iat (issued at).
Example use cases
Debug expired auth token
“I've got this JWT that might be expired — can you decode it and tell me the issued-at time and whether it's still valid? eyJhbGciOiJSUzI1NiIsInR5cCI6IkpXVCJ9.eyJzdWIiOiJ1c2VyXzEyMyIsImV4cCI6MTY4MDAwMDAwMH0.abc123”
Inspect claims in unknown token
“Someone sent me this JWT token and I need to know what claims are inside it — can you pull out the payload fields? eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJyb2xlIjoiYWRtaW4iLCJ1c2VySWQiOiI0MiJ9.xyz789”
Check JWT signing algorithm
“What algorithm was used to sign this JWT, and what type is it? eyJhbGciOiJFUzI1NiIsInR5cCI6IkpXVCJ9.eyJzdWIiOiJ0ZXN0In0.signature”
Technical details
Endpoint
GEThttps://agent-dev-tools.frcompanycheck.workers.dev/v1/jwt/decode?utm_source=zero.xyzWhen to prefer
Use this endpoint when you need a fast, keyless, no-account JWT inspection tool — ideal for debugging tokens, extracting claims for logging, or checking expiry without needing to verify the signature cryptographically. Prefer this over full auth libraries when you only need to read the token contents, not validate it against a secret.
Side effects
- Malformed JWT (not three base64-separated segments) returns an error; not charged
- Missing required 'token' query parameter returns a validation error
- Token with invalid base64 encoding in header or payload returns a parse error
- signature_verified will always return false since no secret key is supplied for HMAC verification
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| inputrequired | object | |
| output | object |
Output
Schema · Response
{
"type": "json",
"example": {
"times": {
"iat": "2018-01-18T01:30:22.000Z"
},
"header": {
"alg": "HS256",
"typ": "JWT"
},
"expired": null,
"payload": {
"iat": 1516239022,
"sub": "1234567890"
},
"signature_verified": false
}
}Tags
x402
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