JWT Decoder Online
Paste a JWT to read its header and payload as JSON. This decoder does not verify signatures and does not need your secret, so you can inspect tokens without sharing keys.
How to use JWT Decoder
Drop the text, table, or snippet that needs jwt decoder into the input box.
Toggle the checkboxes or fields if the tool offers them, then watch the output update.
Use Copy or Save. Because this runs locally, you can work on private data without an account.
Why use this tool?
The Problem
Opaque three-part tokens are hard to debug when claims, expiry, or audience look wrong in production.
The Solution
The tool splits the JWT, Base64URL-decodes header and payload, and pretty-prints the JSON claims.
Common Use Cases
- Debug auth failures
- Check exp and aud claims
- Inspect API tokens in development
How it works
Header and payload segments are decoded from Base64URL. The signature is displayed as-is and is not checked. All calculations and text processing routines execute locally using standard JavaScript inside your browser. No contents are uploaded to any server.
Before / After Example
eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJzdWIiOiIxMjM0IiwibmFtZSI6IkFkYSJ9.signature
{
"alg": "HS256",
"typ": "JWT"
}
{
"sub": "1234",
"name": "Ada"
}Tips & Best Practices
Never paste a live production token into a tool you do not trust. This page stays local, but the token is still a credential on your screen.
Common Mistakes
A decoded JWT is not a verified JWT. Without signature checks, anyone can forge claims.
Frequently Asked Questions
How do I use JWT Decoder online?
Paste your input into JWT Decoder, adjust any options, and copy the result. Decode JSON Web Token scopes without secrets. All processing stays in the tab.
Does JWT Decoder upload my data?
No. JWT Decoder runs in your browser with JavaScript. Answer to Geek does not receive the text, CSV, tokens, or files you paste.
Do I need the secret to decode a JWT?
No. Header and payload are encoded, not encrypted. The secret is only required to verify or sign. Do not share secrets with this or any decoder.
What should I try after JWT Decoder?
Related tools on this site include base64 decode, json formatter, unix timestamp converter. Open those when you need a follow-up transform on the same data.