Web Token & Escape Utilities
Decode JWT headers and claims locally, encode Base64 tokens, or transform URL query parameters. Use this jwt token decode and jwt editor suite completely client-side.
JWT segments will appear here after decoding.
How to Decode JWT Tokens Online
To inspect the contents of your JSON Web Token, paste the raw string (structured as header.payload.signature) into the input editor. The client-side debugger instantly splits the token, decodes the base64-encoded fields, and displays the formatted JSON strings for both the Header and the Payload claim sets.
You can verify the signature integrity by entering your shared secret key or public key in the verification field. The browser compiles the signature local parameters recursively, checking if it matches the token's original signing hash.
Additionally, the utility suite features Base64 and URL encoding/decoding tab panels to escape query strings and transfer binary files safely.
Security & Developer Best Practices
Exposing JWT tokens or client secret keys to cloud servers presents a severe vulnerability. Since credentials, database claims, and signature secrets never leave your local browser sandbox, our tools are fully compliant with corporate security guidelines.
We recommend using cryptographically strong keys generated from our key module (at least 256 bits for HS256) to guard against brute-force off-line signature guessing.
Frequently Asked Questions
Have questions about this tool? Find quick answers here.
- A JSON Web Token (JWT) comprises three parts separated by dots (.):
1. Header: Defines the token type and signing algorithm (e.g., HS256).
2. Payload: Stores the claims or user data.
3. Signature: Verifies that the sender is authentic and the token wasn't modified. - A JWT is typically included in the HTTP headers using the authorization Bearer scheme:
Authorization: Bearer <token>. - JWTs commonly use symmetric signing algorithms like HS256 (HMAC using SHA-256 with a single shared secret) or asymmetric ones like RS256 (RSA private/public key pairs).
- JWT is a standardized, self-contained token format for encoding claims. OAuth is an authorization framework that uses tokens (which could be formatted as JWTs) to delegate API permissions.
- Yes. The Header and Payload are Base64URL-encoded, not encrypted. You can decode and read their contents using our tool without the secret key. However, verifying that the token is valid requires the signature key.
- You can generate cryptographically strong symmetric keys instantly using the Key Generator module. A secure key should consist of random hex or base64 characters.
- For HMAC-SHA256 (HS256), the key must be at least 256 bits (32 bytes) long. Using shorter keys makes the token vulnerable to brute-force offline signature guessing attacks.
Related Utilities
Did You Know?
JWTs (JSON Web Tokens) are split into Header, Payload, and Signature. The payload data is simply Base64Url encoded—not encrypted. Never place passwords or secrets inside JWTs.
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