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.

Clave de API: Opcional; una clave necesita el ámbito api
Consumo de cuota con clave: 1 unidad por llamada
Límite de frecuencia: 60 solicitudes/min por IP

Solicitud

Cuerpo JSON: JwtDecodeRequest

Campo	Tipo	Obligatorio	Descripción
token	string	sí	Compact JWS token. A leading "Bearer " and whitespace are stripped.

Respuestas

200The decoded token (signature not verified).

Campo	Tipo	Obligatorio	Descripción
header	object	sí	cualquier nombre de miembro
payload	object	sí	cualquier nombre de miembro
signaturePresent	boolean	sí
signatureBytes	integer	sí	como mínimo 0
timeClaims	object	sí
timeClaims.exp	TimeClaim	sí
timeClaims.iat	TimeClaim	sí
timeClaims.nbf	TimeClaim	sí
timeClaims.status	object \| null	sí	null when the token carries no usable exp or nbf.
timeClaims.status.kind	string	sí	uno de "expired", "not-yet-valid" o "valid"
timeClaims.status.detail	string	sí
algInfo	AlgInfo	sí
verified	boolean	sí	Always false — this operation never verifies. siempre false
note	string	sí

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

Estado	Significado	Códigos
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

Todas las respuestas de error incluyen el sobre JSON; la tabla de errores explica qué significa cada código y qué hacer.

Ejemplo

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())

Respuesta 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."
}

La respuesta de la API a este ejemplo, generada para esta página el 20 de octubre de 2026; los tiempos relativos y los recuentos de días que contiene se refieren a ese día.

Códigos de error

Código	Estado	Significado
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.

Esquemas

TimeClaim

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

Campo	Tipo	Obligatorio	Descripción
Variante 1value	number	sí	Seconds since the epoch.
Variante 1utc	string	sí
Variante 1relative	string	sí	For example "in 72 years" or "3 minutes ago".
Variante 2error	string	sí

AlgInfo

Classification of the header's alg value.

Campo	Tipo	Obligatorio	Descripción
alg	string \| null	sí
kind	string	sí	uno de "ecdsa", "none", "hmac", "rsa", "eddsa", "missing" o "unknown"
curve	string	no	uno de "P-256", "P-384", "P-521" o "secp256k1"
hash	string	no	uno de "SHA-256", "SHA-384" o "SHA-512"
signatureBytes	integer	no	como mínimo 0
verifiableHere	boolean	sí	Whether POST /v1/jwt/verify can check this token.
summary	string	sí

Error

The error envelope of every non-2xx response.

Campo	Tipo	Obligatorio	Descripción
error	object	sí
error.code	string	sí	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	sí	Human-readable explanation (English).
error.requestId	string	no	The X-Request-Id of this request — quote it when reporting a problem. Sent since v1.1.
error.detail	object	no	Structured context for the error, such as the offending field; omitted when there is none. cualquier nombre de miembro
error.docs	string	no	Where the error codes are explained. Sent since v1.1. formato uri

Todas las operaciones aparecen en la referencia de la API.