# JWT Decoder (Header + Claims, No Verification)

> JWT Decoder (Header + Claims, No Verification) is a paid API for AI agents from twin.unykorn.org, paid per call via x402, $0.002/call, status unknown (last checked 2026-10-01).

Decodes a JWT token's header and claims payload without performing signature verification

## Facts

- Endpoint: POST https://twin.unykorn.org/decode-jwt?utm_source=zero.xyz
- Price: $0.002/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-01
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/jwt-decoder-header-claims-no-verification-6a646522
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_hEdbqk_9aVPz8VRW8DLd9

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-header-claims-no-verification-6a646522 -d '<json body>'
```

Example prompt: Can you decode this JWT for me and show me what's in the header and claims? Here's the token: eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJzdWIiOiIxMjM0NTY3ODkwIiwibmFtZSI6IkpvaG4gRG9lIiwiaWF0IjoxNTE2MjM5MDIyfQ.SflKxwRJSMeKKF2QT4fwpMeJf36POk6yJV_adQssw5c — I just want to read the payload, not verify the signature.

## When to prefer this

Use this endpoint when you need to quickly inspect the contents of a JWT — such as reading claims, checking expiry, or identifying the algorithm — without needing to validate the signature. Prefer it over full JWT verification libraries when you only need to read the payload, when the signing key is unavailable, or when operating in a lightweight agent pipeline that just needs to extract fields like sub, iat, exp, or custom claims. Not appropriate when security-sensitive decisions depend on token authenticity.

## Known failure modes

- Malformed or non-JWT string input may return an error or unparseable result
- Token with missing dot-separated segments will fail to decode
- Base64url decoding errors if the token is truncated or corrupted
- Network or payment processing failure resulting in HTTP 402 or 5xx response

## How this service works

Decode a JWT's header and claims — WITHOUT verifying it — Genesis402 / UnyKorn Operator Network

## Output

Returns a JSON object containing the decoded JWT header fields (e.g. alg, typ, kid) and the decoded claims payload (e.g. sub, iat, exp, iss, aud, custom claims), along with a transaction receipt confirming the x402 micropayment. No signature verification is performed — the output reflects raw encoded content only.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "params": {
   "type": "object",
   "properties": {
    "token": {
     "type": "string"
    }
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "ok": true,
  "type": "decode-jwt",
  "receipt": {
   "tx_hash": "0x<64hex>",
   "amount_usd": 0.002,
   "receipt_id": "g402-<16hex>"
  },
  "generated_at": "<iso8601>"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/jwt-decoder-header-claims-no-verification-6a646522/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from twin.unykorn.org](https://www.zero.xyz/host/twin.unykorn.org/llms.txt)