# agent402.tools JWT Decoder

> agent402.tools JWT Decoder is a paid API for AI agents from agent402.tools, paid per call via x402, $0.001/call, status unknown (last checked 2026-09-14).

Decodes a JWT token to extract its header, payload, expiry status, and time remaining — without verifying the signature.

## Facts

- Endpoint: POST https://agent402.tools/api/jwt-decode
- Price: $0.001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/agent402-tools-jwt-decoder-595cdb72
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_LnD8habyNMDI8yfUs3caB

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 agent402-tools-jwt-decoder-595cdb72 -d '<json body>'
```

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

## When to prefer this

Use this endpoint when you need to inspect or debug a JWT token's contents — its claims, issuer, subject, or expiry — without needing to cryptographically verify its signature. Ideal for debugging, logging, or extracting user info from tokens in trusted contexts.

## Known failure modes

- Malformed JWT string causes a parse error
- Empty or missing token field returns a validation error
- Token with non-standard structure may fail to decode cleanly
- Network timeout on the API request

## How this service works

Decode a JWT without verification: header, payload, expiry status, and time remaining. (Decoding only - signatures are NOT verified.)

## Output

Returns the decoded JWT header (algorithm, token type), the full payload (all claims such as sub, iat, exp, etc.), whether the token is currently expired, and the time remaining until expiry or time since expiry.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "token": {
   "type": "string",
   "description": "The JWT string"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "header": {
   "alg": "HS256"
  },
  "expired": false,
  "payload": {
   "exp": 9999999999,
   "sub": "agent402"
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/agent402-tools-jwt-decoder-595cdb72/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from agent402.tools](https://www.zero.xyz/host/agent402.tools/llms.txt)