JWT Decoder Guide
JWTs are commonly used for API authentication. Decoding them helps you inspect claims and metadata during integration and troubleshooting.
What it is
- A JWT has three dot-separated parts: header, payload, and signature.
- Header defines token metadata, payload contains claims, and signature is used for verification.
Why developers use it
- You can quickly inspect expiration (`exp`) and issuer (`iss`) claims.
- Local decoding helps debug auth flows without sending tokens to external services.
- It speeds up API testing when token claim mismatches cause 401/403 responses.
Example
Sample JWT payload fields
{
"sub": "1234567890",
"name": "John Doe",
"iat": 1516239022
}How to use the tool
- Paste the token into the JWT input box.
- Click Decode to display header and payload as JSON.
- Copy header or payload for debugging and documentation.