Decode a JSON Web Token's header and payload to readable JSON

What it does

Decode a JSON Web Token's header and payload to readable JSON. Pure decoding: signatures are NOT verified and no secret is needed. Accepts standard and URL-safe base64 with or without padding; claims like exp and iat are rendered as dates. Use this when an agent needs to decode header and payload — no verification.

Tags: dev · crypto-dev · analytics · bazaar

Call contract

Method

GET

Input

query parameters

Output

json

Last paid call

2026-10-11

{
  "token": "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJzdWIiOiIxMjM0NTY3ODkwIiwibmFtZSI6IkphbmUgRG9lIiwiaWF0IjoxNzAwMDAwMDAwfQ.dummy_signature_part"
}

{
  "result": {
    "answer": "{\n  \"sub\": \"1234567890\",\n  \"name\": \"Jane Doe\",\n  \"iat\": 1700000000\n}",
    "answerLabel": "Payload claims",
    "details": [
      {
        "label": "Algorithm",
        "value": "HS256"
      },
      {
        "label": "Type",
        "value": "JWT"
      },
      {
        "label": "Signature",
        "value": "present (20 chars) — NOT verified"
      },
      {
        "label": "Time claim",
        "value": "iat: 2023-11-14T22:13:20.000Z"
      }
    ],
    "steps": [
      "Split token on dots",
      "Base64url-decode header and payload",
      "Parse both as JSON (signature left untouched)"
    ],
    "value": null
  },
  "tool": "jwt-decoder"
}

Use with an agent

1. Discover. Agents find this listing with GET https://bazaar.saylorinnovations.com/discovery/search?query=…, the MCP tool search_resources, or /discovery/resources.
2. Inspect. Fetch /resources/35441.json for the price and payment options.
3. Pay. Call GET https://agentstoolshub.com/api/v1/dev/jwt-decoder. The provider answers 402 with its payment requirements. An x402 client signs one of the options below and retries with PAYMENT-SIGNATURE.
4. Execute. The provider returns 200 with the data. Agent Bazaar is not in the request path and never sees your payment.

For humans

You don't need an account or an API key; you need a wallet holding a small amount of USDC on Base, and an x402-capable client (see the examples below). Call the endpoint unpaid first to see exactly what it asks for.

Pricing & payment

Price

$0.003 / request

Protocol

x402 v2

Auth

No account or API key. Pay per request.

Networks

Base

Demand

2 calls · 2 unique payers in 30d (public x402 Bazaar data)

x402 payment requirements

[
  {
    "scheme": "exact",
    "network": "eip155:8453",
    "payTo": "0x8a0F2b0a6C82D1c54B16E2e4DEcd18fF0802b0f6",
    "asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
    "amount": "3000",
    "amountUsd": 0.003,
    "maxTimeoutSeconds": 300
  }
]

Schemas

{
  "properties": {
    "example": {
      "type": "object"
    },
    "type": {
      "type": "string"
    }
  },
  "required": [
    "type"
  ],
  "type": "object"
}

{
  "example": {},
  "type": "string"
}

Examples

curl "https://agentstoolshub.com/api/v1/dev/jwt-decoder"
# -> 402 Payment Required, accepts[] lists how to pay
# retry with a PAYMENT-SIGNATURE (or PAYMENT header) once paid

const res = await fetch("https://agentstoolshub.com/api/v1/dev/jwt-decoder");
if (res.status === 402) {
  const { accepts } = await res.json();
  // pay one of accepts[] via an x402 client, then retry with the payment header
}

import httpx
res = httpx.get("https://agentstoolshub.com/api/v1/dev/jwt-decoder")
if res.status_code == 402:
    accepts = res.json()["accepts"]
    # pay one of accepts[] via an x402 client, then retry with the payment header

Details

Provider

agentstoolshub.com

Endpoint

https://agentstoolshub.com/api/v1/dev/jwt-decoder

Machine-readable

/resources/35441.json