# JWT Decode Tool (x402 USDC Micropayment)

> JWT Decode Tool (x402 USDC Micropayment) is a paid API for AI agents from gpt55.558686.xyz, paid per call via x402, $0.0001/call, status unknown (last checked 2026-09-15).

Decodes a JWT token's header and payload, returning structured claims, paid via x402 USDC micropayment on Base.

## Facts

- Endpoint: GET https://gpt55.558686.xyz/v1/tools/jwt-decode
- Price: $0.0001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/jwt-decode-tool-x402-usdc-micropayment-7dd7c84f
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_xGFdw17Bqf1ZvKue_ZSfC

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-decode-tool-x402-usdc-micropayment-7dd7c84f
```

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

## When to prefer this

Use this endpoint when you need a quick, low-cost ($0.0001 USDC) way to decode and inspect JWT token contents without a subscription, especially in an x402-enabled micropayment workflow on Base. Prefer it over local JWT libraries when operating in agent environments that already support x402 payments and need a simple HTTP call.

## Known failure modes

- Missing or empty 'token' query parameter returns an error
- Malformed JWT string (not three base64 segments) returns a decode error
- Token too long (exceeds 20000 chars) is rejected by schema validation
- Network or payment failure via x402 protocol causes request to fail
- Invalid USDC payment on Base results in 402 payment required response

## How this service works

Decode a JWT header and payload without verifying the signature and without calling an upstream model. Pay up to $0.001 per request with x402 USDC on Base. Public paid calls are limited to 1500 input characters and 128 output tokens.

## Output

Returns a JSON object with ok (boolean), tool name ('jwtDecode'), the decoded JWT header and payload as parsed JSON fields, and a fetchedAt timestamp indicating when the decode occurred.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET",
      "HEAD",
      "DELETE"
     ],
     "type": "string"
    },
    "pathParams": {
     "type": "object",
     "additionalProperties": true
    },
    "queryParams": {
     "type": "object",
     "required": [
      "token"
     ],
     "properties": {
      "token": {
       "type": "string",
       "maxLength": 20000,
       "minLength": 1
      }
     },
     "additionalProperties": false
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object",
     "properties": {
      "ok": {
       "type": "boolean"
      },
      "tool": {
       "type": "string"
      },
      "fetchedAt": {
       "type": "string"
      }
     },
     "additionalProperties": true
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/jwt-decode-tool-x402-usdc-micropayment-7dd7c84f/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from gpt55.558686.xyz](https://www.zero.xyz/host/gpt55.558686.xyz/llms.txt)