# PennyRail JWT Toolkit

> PennyRail JWT Toolkit 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).

Signs, verifies, decodes, and manages JSON Web Tokens (JWTs) via a pay-per-call settlement endpoint

## Facts

- Endpoint: POST https://pennyrail.vercel.app/api/p/skill/jwt.toolkit--jwt-toolkit
- 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-toolkit-b26aa96e
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_VqgInFnPFs5ezDtMMd1sC

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-toolkit-b26aa96e -d '<json body>'
```

Example prompt: Can you decode and verify this JWT for me — eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJzdWIiOiJ1c2VyXzEyMyIsImV4cCI6MTcwMDAwMDAwMH0.abc123 — using the secret 'my-secret-key' and tell me if it's still valid?

## When to prefer this

Choose this endpoint when you need a lightweight, pay-per-call JWT operation without setting up a dedicated auth library or server — ideal for agents that occasionally need to sign, verify, or decode tokens as part of a workflow without persistent auth infrastructure. Suitable for serverless or ad-hoc token inspection tasks.

## Known failure modes

- Invalid or malformed JWT string returns a parse error
- Wrong signing secret causes signature verification failure
- Expired token returns an expiration error with exp claim details
- Unsupported algorithm returns an unsupported algorithm error
- Missing required input fields returns a validation error
- Network or payment settlement failure returns a 402 or 5xx error

## How this service works

Machine-readable settlement service

## Output

Returns a JSON object containing the decoded JWT header and payload claims, verification status (valid/invalid/expired), signature check result, and any error details if the token is malformed or the signature does not match.

## 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-toolkit-b26aa96e/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)