What is JWT Decoder?
Got a JWT token and want to know what is inside? Paste it here and we will break it into its three parts — Header, Payload, and Signature — each formatted as readable JSON. Great for debugging auth issues, checking when a token expires, or just understanding how JWTs work. Your token never leaves your browser.
Use Cases
- ◆Figuring out why an auth flow is failing
- ◆Checking what claims and expiry a token carries
- ◆Inspecting tokens returned by an API
- ◆Learning how JWTs are structured
- ◆Debugging "invalid token" errors
How to Use
- 1Paste your JWT (the long string with two dots)
- 2See Header, Payload, and Signature decoded instantly
- 3Check expiry dates and claims at a glance
- 4Copy any section you need
Features
- ✓Free
- ✓No account needed
- ✓Runs in your browser
- ✓Handles common signing algorithms
- ✓Clean JSON output
- ✓Flags expired tokens
- ✓Nothing uploaded
- ✓Works on any device
FAQ
What exactly is a JWT?
It is a compact, URL-safe string that carries information (claims) between two parties. Most commonly used for authentication — like when you log in and the server hands you a token to prove who you are.
What are the three parts separated by dots?
Header (says which algorithm was used), Payload (the actual data and claims), and Signature (proves the token was not tampered with).
Does this tool send my token anywhere?
No. Decoding happens entirely in your browser.
What operations does this tool support?
This tool supports various operations related to its specific domain. All processing uses modern web APIs for optimal performance.
What are the input limitations?
Input limitations depend on the specific operation. Most tools handle typical use cases instantly with no noticeable delays.
Is my data uploaded to a server?
No. All processing happens locally in your browser using JavaScript APIs. Your data never leaves your device, ensuring complete privacy.