# PennyRail JWT Decode

> PennyRail JWT Decode is a paid API for AI agents from pennyrail.vercel.app, paid per call via x402, $0.05/call, status unknown (last checked 2026-09-14).

Decodes a JWT (JSON Web Token) and returns its header, payload, and signature components without verification

## Facts

- Endpoint: POST https://pennyrail.vercel.app/api/p/skill/jwt.toolkit--jwt-decode
- Price: $0.05/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/pennyrail-jwt-decode-8914c620
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_svq8JbhZkydOFgoT8ZJC6

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 pennyrail-jwt-decode-8914c620 -d '<json body>'
```

Example prompt: Can you decode this JWT for me and show me what's in the payload: eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJzdWIiOiIxMjM0NTY3ODkwIiwibmFtZSI6IkpvaG4gRG9lIiwiaWF0IjoxNTE2MjM5MDIyfQ.SflKxwRJSMeKKF2QT4fwpMeJf36POk6yJV_adQssw5c

## When to prefer this

Choose this endpoint when you need to quickly inspect the contents of a JWT without implementing base64url decoding yourself, when debugging authentication flows to see what claims a token carries, or when you need to extract fields like expiration time or user identity from a token in an automated pipeline. It is not a verification service — if you need to validate the token signature, use a dedicated JWT verification endpoint instead.

## Known failure modes

- Malformed or non-JWT string input returns an error response
- Missing 'input' field or empty object causes validation failure
- Token with non-standard encoding may fail to parse
- Payment failure (402) if USDC balance is insufficient
- Network timeout on the Vercel serverless function cold start

## How this service works

Machine-readable settlement service

## Output

Returns the decoded JWT broken into its three components: the header object (containing algorithm and token type), the payload object (containing all claims such as sub, iat, exp, iss, and any custom fields), and the raw signature string — all without performing cryptographic signature verification.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "object",
 "additionalProperties": true
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/pennyrail-jwt-decode-8914c620/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from pennyrail.vercel.app](https://www.zero.xyz/host/pennyrail.vercel.app/llms.txt)