JWT Decoder API

About the JWT Decoder API

On paid plans, pass a PEM public key, certificate or JWK as publicKey to verify RS, PS, ES and EdDSA signatures and check exp and nbf. HMAC (HS*) secrets and alg none are always refused, and keys are never fetched from URLs.

What people use it for

Token Debugging

Debug and inspect JWT tokens during development to view header and payload contents

Token Analysis

Analyze token structure and claims for free, and verify the signature against a public key on paid plans

Expiration Check

Check token expiration status and view expiration timestamps

Token Inspection

Inspect token contents for troubleshooting authentication issues

Ways to call it

One endpoint, many ways in — REST with JSON, XML, YAML and CSV, plus GraphQL and an MCP interface for AI agents.

JSON

Default REST response

XML

Markup format

YAML

Human-readable

CSV

Tabular export

Beta

GraphQL

Query language

New

MCP

For AI agents

Request parameters — POST /v1/jwtdecoder

Sent as JSON in the request body. Premium parameters are accepted on every plan but only take effect on plans that include them. Anything not listed here is dropped rather than passed through.

Required

Optional

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curl -X POST "https://api.apiverve.com/v1/jwtdecoder" \
  -H "x-api-key: YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"token":"eyJhbGciOiJSUzI1NiIsInR5cCI6IkpXVCIsImtpZCI6InNhbXBsZS1rZXktMSJ9.eyJzdWIiOiIxMjM0NTY3ODkwIiwibmFtZSI6IkpvaG4gRG9lIiwiaXNzIjoiaHR0cHM6Ly9hdXRoLmV4YW1wbGUuY29tIiwiYXVkIjoiYXBpLmV4YW1wbGUuY29tIiwiaWF0IjoxNzY3MjI1NjAwLCJleHAiOjIwODI3NTg0MDB9.hP0O9ELZGk-KN3upyYqdOnPY2Ig7FAzfUY_xytzOCBIhn0_TWdzl2dbLPlj0rkCDsRIQX0I5t9Xv551VI1W9dmvRGtVztyeD3IKHnIn24baOUtjU7Eb6FHL_iWMu5PqMeQJPFytuYbYhzjjCNfFPgAciGgn1Celr8H7_q51x5naMb-nbTvBc5SIX9MBnegGzabExBYQ-OsdKOoYmK0uymNIgC3834jlPuhuJHkPsxX7ncKoSQ4wheiLaZDwFANlT1NrD2XgKyyh-LIIg9CRwqB_WDktZ_R6UusNkLRhKJ20ff29ttkyRhJZzEqRRK60xYn7iPyg4YQni1J_w-oAa_w","publicKey":"-----BEGIN PUBLIC KEY-----\nMIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEA9MiLgWPmLJoEIpAUHVvx\nGyo9vyW9/ryejQyuDZr1m5x0qj5y1otdjN3TwLH1PBQuinSDGiL7O56dfXwy/YIa\nKOhANcJWe78eSDs4oMh3wQnzRfseWZfFgbLHU/nWyXjPE5WRa9F+H5A96KvmatER\nG+kfWUINKR0RUTzox9xSy1KmiaQ5a2GoH3vINioVWBN1zX7Uq6mjCF5nYUMfWDyv\nuUofPWRU2saYdxD2TtVlIs8F62IQU0bnMifFXqmZ5CkmXwPAFJXAIi38Lh/vkOvw\n5B8oeiZd8ZEOLhSYlmhje1IGIwlB8B/ekKnZp4BdKsJYgGka7yn9NTuRsx8U7tfr\n7QIDAQAB\n-----END PUBLIC KEY-----"}'

Authentication

Send your key in the x-api-key header. That is the only auth step — no token exchange, and no per-endpoint scope to configure.

Response — POST /v1/jwtdecoder

Every APIVerve endpoint returns the same three top-level keys, so one response handler covers your whole integration: status, error and data. Only data changes shape.

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{
  "status": "ok",
  "error": null,
  "data": {
    "header": {
      "alg": "RS256",
      "typ": "JWT",
      "kid": "sample-key-1"
    },
    "payload": {
      "sub": "1234567890",
      "name": "John Doe",
      "iss": "https://auth.example.com",
      "aud": "api.example.com",
      "iat": 1767225600,
      "exp": 2082758400
    },
    "signature": "hP0O9ELZGk-KN3upyYqdOnPY2Ig7FAzfUY_xytzOCBIhn0_TWdzl2dbLPlj0rkCDsRIQX0I5t9Xv551VI1W9dmvRGtVztyeD3IKHnIn24baOUtjU7Eb6FHL_iWMu5PqMeQJPFytuYbYhzjjCNfFPgAciGgn1Celr8H7_q51x5naMb-nbTvBc5SIX9MBnegGzabExBYQ-OsdKOoYmK0uymNIgC3834jlPuhuJHkPsxX7ncKoSQ4wheiLaZDwFANlT1NrD2XgKyyh-LIIg9CRwqB_WDktZ_R6UusNkLRhKJ20ff29ttkyRhJZzEqRRK60xYn7iPyg4YQni1J_w-oAa_w",
    "isExpired": false,
    "expiresAt": "2036-01-01T00:00:00.000Z",
    "issuedAt": "2026-01-01T00:00:00.000Z",
    "tokenAge": "309 days",
    "algorithm": "RS256",
    "expiresIn": 288757380,
    "notYetValid": false,
    "securityAnalysis": {
      "isUnsecured": false,
      "hasExpiration": true,
      "isLongLived": true,
      "issues": [
        "Token lifetime exceeds 24 hours"
      ]
    },
    "warning": "Signature verified with the supplied public key.",
    "signatureVerification": {
      "verified": true,
      "algorithm": "RS256",
      "keyType": "RSA",
      "reason": null,
      "claimsValid": true,
      "claimsReason": null
    }
  }
}

Response fields

Paths are relative to data. Premium fields are absent rather than zeroed on plans that do not include them, so check for presence instead of comparing to 0.

Response headers

Every response carries your balance, so your own code always knows where it stands without polling anything. All four are exposed to browsers through CORS.

Errors

Read the HTTP status first, then error for the specific reason. The body names the parameter that has to change.

What a call costs — 1 credits per call

Credits are shared across every APIVerve API — one balance, one key, one bill. Failed requests never count against it, so a rejected input costs nothing.

Calls are what the credits buy at this API's rate — spend them here, on any of the other APIs, or across both. Nothing is reserved per endpoint.

Zero-code embed — one snippet, no backend

Drop an interactive JWT Decoder form onto any page. The widget calls the API for you, so no key ever appears in your markup and there is nothing to deploy.

Changelog — JWT Decoder API

Every change to this endpoint, newest first. Breaking changes ship as a new version and the previous one keeps serving — response fields are added, never removed or retyped in place, so an integration written against v1 keeps working.

Currently v1