# JWT Decoder & Claims Inspector

> JWT Decoder & Claims Inspector is a paid API for AI agents from artifact-inspector.use.x402atlas.com, paid per call via x402, $0.005/call, status unknown (last checked 2026-09-14).

Parses a compact JWS (JWT) token to extract unverified header and claims, and evaluates advisory NumericDate fields without signature verification or URL fetching.

## Facts

- Endpoint: POST https://artifact-inspector.use.x402atlas.com/jwt
- Price: $0.005/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/jwt-decoder-claims-inspector-6a322025
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_06E3mj886exZNt0Met6D7

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability jwt-decoder-claims-inspector-6a322025 -d '<json body>'
```

Example prompt: Can you decode this JWT for me and tell me what's in the header and claims, including whether it looks expired? Here's the token: eyJhbGciOiJSUzI1NiIsImtpZCI6ImFiYzEyMyJ9.eyJzdWIiOiJ1c2VyXzQ1NiIsImV4cCI6MTcwMDAwMDAwMCwiaWF0IjoxNjk5OTAwMDAwfQ.signature

## When to prefer this

Use this endpoint when you need to inspect the contents of a JWT without access to the signing key — for debugging, logging, introspection, or extracting claims for routing logic. Prefer this over a full verification endpoint when you explicitly don't need cryptographic validation, need fast stateless parsing, or are working in a context where fetching JWKs is not feasible. It complements the sibling JWK inspector if you later need to validate the key itself.

## Known failure modes

- Malformed or non-compact JWT string returns a parse error
- Missing or empty token body results in a 400-level error
- Tokens with non-standard encoding may fail to parse
- NumericDate evaluation is advisory only and may not reflect clock skew
- No signature verification means tampered tokens will still decode successfully

## How this service works

JSON Web Token (JWT) decoder — parse an unverified compact JWS header and claims and evaluate advisory NumericDate times without signature verification or URL fetching.

## Output

Returns the decoded JWT header (algorithm, type, key ID, etc.), the full claims payload (sub, iss, aud, exp, iat, and any custom claims), and advisory evaluations of NumericDate fields such as whether the token appears expired or not-yet-valid — all without performing signature verification or fetching remote keys.

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/jwt-decoder-claims-inspector-6a322025/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from artifact-inspector.use.x402atlas.com](https://www.zero.xyz/host/artifact-inspector.use.x402atlas.com/llms.txt)