$ man jwt-decode
/jwt-decode
PRICE / CALL
$0.003
USDC · base mainnet · scheme: exact
METHOD
POST
CLUSTER
webprobeCATEGORY
utilities
STATUS
● live
NAME
jwt-decode — decodes a jwt and inspects its claims without needing the signing key
SYNOPSIS
POST https://x402.agentutility.ai/jwt-decode
Content-Type: application/json
X-PAYMENT: <signed-transferWithAuthorization>
{ ... }↳ first call →
402 Payment Required. Sign USDCtransferWithAuthorization, retry with theX-PAYMENT header.DESCRIPTION
Decodes a JWT and inspects its claims without needing the signing key. Base64URL-decodes header and payload, parses standard claims (iss, aud, sub, exp, iat, nbf, jti), and reports algorithm, key id (kid), token type (typ), TTL, and clock-validity (is_expired / is_not_yet_valid / is_currently_valid_by_clock). Does NOT verify signatures — for inspection only, never trust output for auth decisions. Use it as a JWT parser, JSON Web Token inspector, Bearer token debugger, OAuth ID-token reader, or Auth0 + Cognito + Firebase token inspector.
INPUT — request schema
| property | type | description | req? |
|---|---|---|---|
| jwt | string | Compact-serialization JWT string (three base64url segments separated by '.'). May be prefixed with 'Bearer ' — that prefix is stripped automatically. | required |
OUTPUT — response shape
| field | type | description |
|---|---|---|
| header | object | Decoded JWT header object with parsed JOSE fields like alg, typ, kid, and any custom header parameters. |
| payload | object | Decoded JWT payload object with all claims parsed from the base64url-decoded middle segment. |
| signature | string | Raw signature segment from the JWT as a base64url string; not verified by this endpoint. |
| algorithm | string | Signing algorithm declared in the header's alg field, such as HS256, RS256, ES256, or none. |
| key_id | string | Key identifier from the header's kid field, used by verifiers to select the right signing key. |
| type | string | Token type from the header's typ field, typically JWT but sometimes at+jwt or similar variants. |
| claims | object | Standard JWT claims extracted from payload: iss, aud, sub, jti, iat, exp, nbf with parsed timestamps. |
| is_expired | boolean | True if exp claim is present and the expiration timestamp is in the past relative to server clock. |
| is_not_yet_valid | boolean | True if nbf claim is present and the not-before timestamp is in the future relative to server clock. |
| is_currently_valid_by_clock | boolean | True if the token is neither expired nor not-yet-valid by clock; signature validity is not checked. |
| payload_size_bytes | number | Byte length of the decoded payload JSON, useful for spotting oversized tokens. |
| note | string | Reminder that this endpoint only decodes and clock-checks; it does not cryptographically verify signatures. |
EXAMPLES — two ways to call
EXAMPLE 1 · curl
curl -X POST https://x402.agentutility.ai/jwt-decode \
-H 'Content-Type: application/json' \
-d '{ }'first response =
402 Payment Required with payment requirements; sign + retry with X-PAYMENT.EXAMPLE 2 · mcp
# Install the MCP package for this endpoint's cluster npx -y @agentutility/mcp-<cluster> # Required: EVM private key with USDC on Base export X402_PRIVATE_KEY=0x... # Then call the jwt-decode tool from your MCP-aware agent.
MCP server handles payment automatically — your coding agent just calls the tool by name.
METADATA
- tags
- jwttokenauthdebugdeveloper
- methods
- POST
- cluster
- webprobe
- price
- $0.003 USDC per call
ADJACENT — other endpoints in webprobe
| endpoint | description | price |
|---|---|---|
| crates-io-stats | Fetches the public crates.io API record for a Rust crate and returns description, license, repository, homepage, documentation, keywords,… | $0.003 |
| crypto-news-api | Returns recent cryptocurrency headline metadata and sentiment. | $0.003 |
| homoglyph-check | Detects Unicode lookalike characters that impersonate ASCII Latin letters, a common phishing-domain trick. | $0.003 |
| npm-package-stats | Fetches the public npm registry record for a package and returns description, license, repository, latest version, total version count, r… | $0.003 |
| pypi-package-stats | Fetches the public PyPI JSON record for a Python package and returns summary, license, homepage, repository, documentation, issues URL, a… | $0.003 |
| url-metadata-extract | Extracts page metadata from any URL: title, description, Open Graph and Twitter Card tags, canonical link, and favicon. | $0.003 |
| keyword-suggest | Keyword and autocomplete suggestions for any seed query. | $0.002 |
| arxiv-bibtex | Turns an arXiv paper into a BibTeX entry: pulls title, authors, year, abstract, and DOI from the arXiv API and generates a properly-forma… | $0.005 |
SEE ALSO