JWT

Decode a JWT (no signature check)

POSThttps://ecdsa.com/api/v1/jwt/decode

Decodes a compact JWS token: header, payload, enriched exp/iat/nbf time claims and a classification of the algorithm. The signature is NOT verified — the response carries verified: false explicitly. Use /v1/jwt/verify to check ES* signatures.

API-Schlüssel: Optional; ein Schlüssel braucht den Scope api
Kontingentverbrauch mit Schlüssel: 1 Einheit pro Aufruf
Rate Limit: 60 Anfragen/min pro IP

Anfrage

JSON-Body: JwtDecodeRequest

Feld	Typ	Erforderlich	Beschreibung
token	string	ja	Compact JWS token. A leading "Bearer " and whitespace are stripped.

Antworten

200The decoded token (signature not verified).

Feld	Typ	Erforderlich	Beschreibung
header	object	ja	beliebige Feldnamen
payload	object	ja	beliebige Feldnamen
signaturePresent	boolean	ja
signatureBytes	integer	ja	mindestens 0
timeClaims	object	ja
timeClaims.exp	TimeClaim	ja
timeClaims.iat	TimeClaim	ja
timeClaims.nbf	TimeClaim	ja
timeClaims.status	object \| null	ja	null when the token carries no usable exp or nbf.
timeClaims.status.kind	string	ja	einer der Werte "expired", "not-yet-valid" oder "valid"
timeClaims.status.detail	string	ja
algInfo	AlgInfo	ja
verified	boolean	ja	Always false — this operation never verifies. immer false
note	string	ja

Header: X-Request-Id · X-RateLimit-Limit · X-RateLimit-Remaining · X-RateLimit-Reset · X-Quota-Limit · X-Quota-Remaining · X-Quota-Reset

Status	Bedeutung	Codes
400	Bad request. Input limits: a request body of at most 100 KB (a larger one is answered with 413) and arrays and objects nested at most 64 levels deep, JSON documents inside string fields included.	invalid_json missing_field invalid_input private_key_rejected
401	Unauthorized.	unauthorized
403	Forbidden.	forbidden_scope
404	Not found.	not_found
405	Method not allowed.	method_not_allowed
413	Payload too large.	payload_too_large
429	Too many requests.	rate_limited quota_exceeded
500	Internal server error.	internal_error
503	Service unavailable.	service_unavailable
504	Gateway timeout.	timeout

Jede Fehlerantwort enthält das JSON-Fehlerobjekt; die Fehlertabelle erklärt, was jeder Code bedeutet und was zu tun ist.

Beispiel

An ES256 token

curl

curl -sS 'https://ecdsa.com/api/v1/jwt/decode' \
  -H 'content-type: application/json' \
  -d '{
  "token": "eyJhbGciOiJFUzI1NiIsInR5cCI6IkpXVCIsImtpZCI6ImNvcHBlci1leGFtcGxlLTEifQ.eyJpc3MiOiJodHRwczovL2lzc3Vlci5leGFtcGxlLmNvbSIsInN1YiI6InVzZXJfNDIiLCJhdWQiOiJlY2RzYSIsImlhdCI6MTc4NzE0MDgwMCwiZXhwIjo0MDcwOTA4ODAwfQ.fQpTQxkahGRlZp-U71-xNk68mpZH23dhn9QoysMLmZfBx_e-vd9sCgh7sJ4eXu0-WbQSNqzmVPyUKErCJx4DHw"
}'

JavaScript (fetch)

const response = await fetch("https://ecdsa.com/api/v1/jwt/decode", {
  method: "POST",
  headers: { "content-type": "application/json" },
  body: JSON.stringify({
    "token": "eyJhbGciOiJFUzI1NiIsInR5cCI6IkpXVCIsImtpZCI6ImNvcHBlci1leGFtcGxlLTEifQ.eyJpc3MiOiJodHRwczovL2lzc3Vlci5leGFtcGxlLmNvbSIsInN1YiI6InVzZXJfNDIiLCJhdWQiOiJlY2RzYSIsImlhdCI6MTc4NzE0MDgwMCwiZXhwIjo0MDcwOTA4ODAwfQ.fQpTQxkahGRlZp-U71-xNk68mpZH23dhn9QoysMLmZfBx_e-vd9sCgh7sJ4eXu0-WbQSNqzmVPyUKErCJx4DHw"
  }),
});
console.log(response.status, await response.json());

Python (httpx)

import httpx

response = httpx.post(
    "https://ecdsa.com/api/v1/jwt/decode",
    json={
        "token": "eyJhbGciOiJFUzI1NiIsInR5cCI6IkpXVCIsImtpZCI6ImNvcHBlci1leGFtcGxlLTEifQ.eyJpc3MiOiJodHRwczovL2lzc3Vlci5leGFtcGxlLmNvbSIsInN1YiI6InVzZXJfNDIiLCJhdWQiOiJlY2RzYSIsImlhdCI6MTc4NzE0MDgwMCwiZXhwIjo0MDcwOTA4ODAwfQ.fQpTQxkahGRlZp-U71-xNk68mpZH23dhn9QoysMLmZfBx_e-vd9sCgh7sJ4eXu0-WbQSNqzmVPyUKErCJx4DHw",
    },
    timeout=30.0,
)
print(response.status_code, response.json())

Antwort 200

{
  "header": {
    "alg": "ES256",
    "typ": "JWT",
    "kid": "copper-example-1"
  },
  "payload": {
    "iss": "https://issuer.example.com",
    "sub": "user_42",
    "aud": "ecdsa",
    "iat": 1787140800,
    "exp": 4070908800
  },
  "signaturePresent": true,
  "signatureBytes": 64,
  "timeClaims": {
    "exp": {
      "value": 4070908800,
      "utc": "2099-01-01 00:00:00 UTC",
      "relative": "in 72 years"
    },
    "iat": {
      "value": 1787140800,
      "utc": "2026-08-19 12:00:00 UTC",
      "relative": "61 days ago"
    },
    "nbf": null,
    "status": {
      "kind": "valid",
      "detail": "valid until 2099-01-01 00:00:00 UTC (in 72 years)"
    }
  },
  "algInfo": {
    "alg": "ES256",
    "kind": "ecdsa",
    "curve": "P-256",
    "hash": "SHA-256",
    "signatureBytes": 64,
    "verifiableHere": true,
    "summary": "ES256 is ECDSA on P-256 with SHA-256; the JWS signature is raw r‖s (64 bytes). POST /api/v1/jwt/verify can check it."
  },
  "verified": false,
  "note": "This endpoint decodes the token without checking the signature. Use POST /api/v1/jwt/verify (ES256/ES384/ES512) to verify it against a public key."
}

Die Antwort der API auf dieses Beispiel, erzeugt für diese Seite am 20. Oktober 2026; relative Zeitangaben und Tageszahlen darin beziehen sich auf diesen Tag.

Fehlercodes

Code	Status	Bedeutung
invalid_json	400	The body is not valid JSON or not a JSON object; or the input nests arrays and objects more than 64 levels deep (JSON documents inside string fields count too), or is too complex to inspect for private keys.
missing_field	400	A required field is absent or empty.
invalid_input	400	A field could not be parsed — the message explains exactly why.
private_key_rejected	400	The request contains private-key material (a PEM PRIVATE KEY block, an OpenSSH, SSH2 or PuTTY private key, or a JWK with "d"). Never send private keys anywhere.
unauthorized	401	The Authorization or X-API-Key header is malformed, the API key is not valid (wrong checksum, unknown, revoked or expired), or the operation needs a key.
forbidden_scope	403	The API key is valid but lacks a scope this operation requires; the message names it.
not_found	404	No operation exists at this path.
method_not_allowed	405	The path exists but does not accept this HTTP method; see the Allow header.
payload_too_large	413	The body exceeds 100 KB.
rate_limited	429	Too many requests — see Retry-After.
quota_exceeded	429	A daily or monthly quota of the API key's account is used up. X-Quota-Reset (and Retry-After) say when it starts over; retrying earlier cannot succeed.
internal_error	500	Unexpected server error.
service_unavailable	503	API keys cannot be verified right now (the key store is unreachable); retry shortly.
timeout	504	The operation did not finish within its time budget.

Schemas

TimeClaim

null when the claim is absent; {error} when it is malformed.

Feld	Typ	Erforderlich	Beschreibung
Variante 1value	number	ja	Seconds since the epoch.
Variante 1utc	string	ja
Variante 1relative	string	ja	For example "in 72 years" or "3 minutes ago".
Variante 2error	string	ja

AlgInfo

Classification of the header's alg value.

Feld	Typ	Erforderlich	Beschreibung
alg	string \| null	ja
kind	string	ja	einer der Werte "ecdsa", "none", "hmac", "rsa", "eddsa", "missing" oder "unknown"
curve	string	nein	einer der Werte "P-256", "P-384", "P-521" oder "secp256k1"
hash	string	nein	einer der Werte "SHA-256", "SHA-384" oder "SHA-512"
signatureBytes	integer	nein	mindestens 0
verifiableHere	boolean	ja	Whether POST /v1/jwt/verify can check this token.
summary	string	ja

Error

The error envelope of every non-2xx response.

Feld	Typ	Erforderlich	Beschreibung
error	object	ja
error.code	string	ja	Machine-readable error code. Each response lists the codes it can carry; new codes may be added within v1, so treat an unknown code by its HTTP status.
error.message	string	ja	Human-readable explanation (English).
error.requestId	string	nein	The X-Request-Id of this request — quote it when reporting a problem. Sent since v1.1.
error.detail	object	nein	Structured context for the error, such as the offending field; omitted when there is none. beliebige Feldnamen
error.docs	string	nein	Where the error codes are explained. Sent since v1.1. Format uri

Alle Operationen findest du in der API-Referenz.