Inspect JSON Web Token headers, payloads, and timestamps locally in your browser with zero network transmission.
This tool parses Base64URL claims for local debugging. It does not verify cryptographic signatures without access to your application's private key or HMAC secret.
The Todoal JWT Decoder is a secure, browser-native developer tool engineered to decode, parse, and inspect JSON Web Tokens (RFC 7519) instantly. Used extensively in OAuth 2.0, OpenID Connect, and modern single-sign-on (SSO) architectures, JWTs encapsulate authentication credentials and user claims inside a three-part dot-separated Base64URL string (header.payload.signature).
Our in-browser decoding engine splits and decodes the JWT header and payload in real time, formatting the JSON claims into clean, indented trees. It also evaluates standard timestamp claims—such as Expiration Time (exp), Issued At (iat), and Not Before (nbf)—displaying human-readable dates and live expiration countdown statuses.
Instantly converts Unix epoch timestamps (exp, iat, nbf) into local human-readable date-time strings with live expired/active status indicators.
Separates the cryptographic signing algorithm (HS256, RS256, ES256) in the header from user identity claims, roles, and permissions in the payload.
Restructures raw decoded claims into clean, indented JSON with customizable indentation for effortless debugging and clipboard copying.
All decoding executes completely in browser RAM. Your authentication tokens, API keys, user IDs, and permissions never leave your device.
Token inspection is a core component of web API security. Format decoded JSON payload claims with our JSON Formatter, validate JSON schemas with the JSON Validator, explore nested claims in the JSON Viewer, and convert Unix epoch timestamps with the Unix Timestamp Converter or Timestamp Converter.
For encoding and token creation workflows, decode Base64 data using the Base64 Decoder, encode data with the Base64 Encoder, test auth regex patterns with the Regex Tester, and generate cryptographically random session IDs using the UUID Generator. Explore all utilities in the Developer Tools Suite.
eyJhbGciOi...) into the input box.Inspects the JOSE header to identify signing algorithms (HS256, RS256, ES256), Key IDs (kid), and token types (typ) to diagnose authentication mismatches.
Extracts issuer (iss), subject (sub), audience (aud), roles, scopes, and custom claims into formatted JSON for rapid API authentication debugging.
JSON Web Tokens are digitally signed using cryptographic keys. While decoding a token's payload reveals its claims, verifying the cryptographic signature requires the corresponding secret key or public RSA/ECDSA certificate. Because tokens often contain sensitive authorization scopes and user IDs, decoding them locally inside browser RAM without transmitting payloads to remote servers guarantees that your authentication tokens remain strictly confidential.
When microservices reject incoming authentication tokens with HTTP 401 Unauthorized errors, diagnosing whether the failure is caused by an expired token (exp claim), a clock skew mismatch (nbf claim), or an invalid algorithm header (alg claim) is critical. Todoal's JWT Decoder instantly parses and displays token claims in clear, readable JSON, highlighting expiration states and issuer origins so backend and frontend engineers can resolve authentication bugs in seconds.
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