Decodes a JWT (up to 16 KB)
Decodes a JWT (up to 16 KB): header, payload, registered claims as ISO dates, expired and not-yet-valid flags, algorithm and signature length. With jwksUrl (public https) the signature is checked with WebCrypto for RS, PS and ES algorithms against the matching key. 'none' is never accepted; HMAC needs the secret. Tokens are secrets: this tool does not store or log them.
Answeringour last check, 2026-10-18
1 of 1checks answered this week
30 msmedian answer time
$0.001listed price per call
$0.001price it asked us
Paid test badge: not yet. The checks above are free: we call the tool without paying and read the payment request it sends back. The Verified badge needs paid calls whose answers match the promised output, and nobody can buy a badge.
Endpoint
GET https://api.sitecheck-api.workers.dev/api/jwt/decode
| Category | Commerce and shopping |
|---|---|
| Provider host | api.sitecheck-api.workers.dev |
| Networks | eip155:5042, eip155:8453, solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp |
| Payment schemes | exact |
| Self-reported calls, 30 days | 2 from 2 payers (the provider's figure, not ours) |
Our checks, last 30 days
| Day | Result | HTTP | Asked | Time |
|---|---|---|---|---|
| 2026-10-18 | valid payment request | 402 | $0.001 | 30 ms |
Example input (from the provider)
{
"method": "GET",
"queryParams": {
"token": "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJzdWIiOiIxMjM0NTY3ODkwIiwiaWF0IjoxNTE2MjM5MDIyfQ.SflKxwRJSMeKKF2QT4fwpMeJf36POk6yJV_adQssw5c"
},
"type": "http"
}
Promised output schema (from the provider)
{
"$schema": "https://json-schema.org/draft/2020-12/schema",
"properties": {
"input": {
"additionalProperties": false,
"properties": {
"method": {
"enum": [
"GET"
],
"type": "string"
},
"queryParams": {
"properties": {
"jwksUrl": {
"description": "Public https URL of the JWKS to verify with (optional)",
"type": "string"
},
"token": {
"description": "The JWT, three base64url parts separated by dots (up to 16 KB)",
"type": "string"
}
},
"required": [
"token"
],
"type": "object"
},
"type": {
"const": "http",
"type": "string"
}
},
"required": [
"type",
"method"
],
"type": "object"
},
"output": {
"properties": {
"example": {
"type": "object"
},
"type": {
"type": "string"
}
},
"required": [
"type"
],
"type": "object"
}
},
"required": [
"input"
],
"type": "object"
}