//
No customization controls needed for this tool. It transforms text automatically!
Supports text inputs up to 50 MB. Computations execute entirely within your local browser memory with zero server uploads.
sub), role permissions, issued-at timestamps (iat), and expiration dates (exp)—without sending sensitive tokens to remote servers. The JWT Payload Decoder parses and displays token headers and claims in real time with human-readable timestamp conversions and expiration status alerts.A standard JWT is composed of three distinct sections separated by dots (.):
$$\text{JWT} = \underbrace{\text{Header}}_{\text{Base64URL}} \, . \, \underbrace{\text{Payload}}_{\text{Base64URL}} \, . \, \underbrace{\text{Signature}}_{\text{HMAC / RSA}}$$
"alg": "HS256" or "RS256") and token type ("typ": "JWT").sub (Subject): The unique user ID or account identifier.iat (Issued At): Unix epoch timestamp when the token was generated.exp (Expiration Time): Unix epoch timestamp when the token expires.nbf (Not Before): Timestamp before which the token must not be accepted."roles": ["admin"]), email addresses, and tenant identifiers.Our inspector automatically translates numeric Unix epoch timestamps (exp: 1772345678) into formatted local dates (e.g. August 29, 2026, 10:15 AM), flagging expired tokens in red.
eyJhbGci...) into the editor workspace.alg) and token type.iat, exp, and nbf into human-readable local dates.Scenario: Inspecting user role claims and expiration time on an OAuth access token.
eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJzdWIiOiIxMjM0NTY3ODkwIiwibmFtZSI6IkFsZXggQ2hlbiIsImFkbWluIjp0cnVlLCJleHAiOjE3NzIzNDU2Nzh9.signature
Header: {"alg": "HS256", "typ": "JWT"}
Payload: {"sub": "1234567890", "name": "Alex Chen", "admin": true, "exp": 1772345678}
Status: Token Active ✅Decodes claims and translates expiration timestamp into readable date.
Scenario: Debugging why an API request returned a 401 Unauthorized error.
JWT with exp set to a past timestamp
Status: EXPIRED ❌ (Expired on May 12, 2024)
Alerts the developer that the token has expired.