JWT Decoder - Private Token Claim Inspector

How to use this JWT Decoder

1. Paste your input into the editor, or load a local file if the tool supports it.
2. Choose any available options for the result you want.
3. Click Decode JWT to process the data in your browser.
4. Review the output, then copy or download the result.

JWT Decoder example

Before:

eyJhbGciOiJIUzI1NiJ9.eyJzdWIiOiIxMjMifQ.sig

After:

Header and payload JSON with algorithm, subject, and readable dates when present.

What this tool does

JWT Decoder reads the header and payload sections of a JSON Web Token and displays the decoded JSON.

Use it to inspect claims, scopes, subject values, issued-at times, not-before times, and expiry timestamps while debugging authentication flows.

This tool decodes only. It does not verify signatures and does not prove that a token is valid, trusted, active, or unmodified.

Normal JWT decoding runs locally in your browser, but you should still avoid pasting production tokens unless your policy allows it.

When to use JWT Decoder

• Decode tokens, Base64 values, hashes, or URL-encoded strings.
• Prepare encoded values for API testing and debugging.
• Inspect claims and encoded values without uploading sensitive text.

Limitations and safe-use notes

• This page decodes JWT header and payload data but does not prove that the token signature is valid.
• Decoding a JWT does not mean the token is trusted, active, unexpired, or safe to use.
• Do not paste production access tokens unless your organization allows browser-side inspection.
• Very large inputs depend on your browser memory, CPU, and device performance.
• The tool is designed for developer workflows, examples, configs, exports, and debugging, not for replacing security-critical internal systems.
• Avoid pasting production passwords, private API keys, medical records, financial records, or regulated customer data unless your policy allows it.

Common mistakes and warnings

• Decoded JWT data is not proof that a token is valid.
• Do not paste production secrets into random websites; this tool is local but caution is still good security practice.
• Bearer prefixes and whitespace should be removed before decoding.

Privacy and browser processing

This page is static and the tool runtime runs on your device. Heavy work is sent to a browser Web Worker where possible. Local file loading uses the File API, generated downloads use Blob URLs, and no online save or share-result feature is included because that would weaken the privacy promise.

For normal tool usage, your pasted text or loaded file content is not sent to a server by this tool. This makes the page safer for formatting, converting, validating, or inspecting developer data that you do not want to upload elsewhere.

You can check this yourself by opening your browser developer tools, using the Network tab, and watching requests while processing sample input. See the verify no upload guide for step-by-step instructions.

Related tools and next steps