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JWT Toolkit – Verify
x402
JWT Toolkit – Verify is a paid API for AI agents from jwt.openverbs.com, paid per call via x402, $0.004/call, status unknown (last checked 2026-09-14).
Verifies a compact JWT token's signature, expiration, and claims against a provided key
Price / call$0.004
Success—
StatusUnknown
How this service works
Verify a JSON Web Token's signature and claims against a shared secret (HS*) or a PEM public key (RS/ES/PS). Returns { valid, payload } on success or { valid: false, reason } for a bad signature, expired/not-yet-active token, or a failed issuer/audience/subject check. Pass `algorithms` to pin the accepted signing algorithms and prevent algorithm-confusion attacks.
Output
The endpoint returns a verification result indicating whether the JWT is valid, along with the decoded payload claims (such as sub, iss, aud, exp, iat) if verification succeeds, or a structured error message describing the failure reason (invalid signature, expired token, claim mismatch, unsupported algorithm, etc.).
Example use cases
Validate incoming API bearer token
“Check whether this JWT bearer token is valid before I let it through: token is 'eyJhbGciOiJSUzI1NiJ9...', use this PEM public key, only allow RS256, and require the audience to be 'api.myservice.com'.”
Confirm user session token on login
“Verify the user's session JWT — token is 'eyJhbGciOiJIUzUxMiJ9...', shared secret is 's3cr3t!', accept HS512 only, and make sure the subject matches 'user_12345'.”
Audit expired token with clock tolerance
“I need to verify an older JWT that might be slightly expired — token is 'eyJhbGciOiJFUzI1NiJ9...', use this PEM EC public key, allow ES256, and give it up to 30 seconds of clock skew tolerance.”
Technical details
Endpoint
POSThttps://jwt.openverbs.com/v1/verifyWhen to prefer
Use this endpoint when you need a lightweight, pay-per-call JWT verification service without managing your own cryptography libraries or authentication infrastructure. It is particularly useful in agent workflows that need to validate incoming tokens from users or downstream services before proceeding, or in serverless/edge contexts where installing JWT libraries is inconvenient. Supports the full range of HMAC (HS256/384/512), RSA (RS256/384/512, PS256/384/512), and EC (ES256/384/512) algorithms, making it versatile across auth systems.
Side effects
- Invalid or tampered token signature returns a verification failure response
- Expired token without ignoreExpiration flag causes validation to fail
- Algorithm not in the allowed list triggers an algorithm mismatch error
- Issuer, subject, or audience claim mismatch returns a claim validation error
- Malformed JWT (not three base64url segments) returns a parse error
- Incorrect or mismatched key type (e.g. HMAC secret used for RS256 token) causes signature failure
- Missing required fields (token or key) returns a 400-level error
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| inputrequired | object |
Tags
x402
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