Decode a JSON Web Token into its header, payload and signature — verify HS256/384/512 signatures with your secret.
A Jwt Decoder Online tool helps you instantly decode JSON Web Tokens. Instead of manually splitting Base64URL strings, paste your token and immediately see the header, payload, and signature. This free tool also lets you verify jwt signature using HMAC algorithms, making it perfect for developers who need to decode json web token data quickly. This online jwt parser provides you with complete transparency in a matter of seconds, regardless of whether you’re debugging authentication flows or checking claim data.
Paste from clipboard – read tokens directly from your clipboard with a single click
File upload support – load .txt or .jwt files using the File button or drag and drop
Fetch from URL – retrieve JWTs from any remote endpoint using the URL button
Sample token included – load a demo JWT with a preset secret to test the tool instantly
Auto-decode on input – tokens decode automatically as soon as you paste or type
Three-part JWT display – separate boxes for header, payload, and signature with color-coded headers
HS256 / HS384 / HS512 verification – validate signatures using your secret key and a dropdown algorithm selector
Claims metadata – automatically shows iat, exp, and nbf timestamps with expiration warnings
Copy decoded JSON – one click to copy the full decoded object to your clipboard
Export results – download the decoded JSON as a file for offline reference
Adjustable editor – toggle word wrap, increase or decrease font size, and view line numbers
Cursor and size info – displays current line/column position and input file size
Paste a JWT into the main text area, upload a file, or fetch from a URL.
– the header and payload appear instantly in the output panel.
Enter your secret key, choose an algorithm, and click the Verify button.
Use the copy icon or download button to save the decoded JSON.
Ht the Clear button to reset all fields and begin a new token inspection.
How do I decode a JWT? Just paste it – the tool does the rest for you.
No submit button required – tokens decode as soon as you paste them into the editor.
Upload local files, fetch from URLs, or paste from the clipboard – whichever is easiest.
Expiration (exp) and not-before (nbf) timestamps are highlighted so you know if a token is active.
Validate token authenticity with HS256, HS384, or HS512 using a supplied secret key.
Header, payload, and signature are displayed in separate, color-coded boxes for quick scanning.
Download the decoded JSON or copy it to your clipboard with a single button press.
Check expiration first – always look at the exp claim; if the time has passed, the token is invalid.
Let Auto detect the algorithm – the dropdown defaults to “Auto”, which reads the algorithm directly from the header to avoid mismatches.
Double-check your secret – HMAC verification fails if the secret key doesn’t exactly match the one used to sign the original token.
When you decode a token with this Jwt Decoder Online, you see exactly what makes it work. The header reveals the signing algorithm – often HS256 or RS256. The payload holds all the claims: user identifiers, roles, permissions, and time-based values like iat (issued at) and exp (expiration). The signature is the cryptographic proof that the token hasn’t been altered. This tool separates all three parts so you can inspect each layer without manually decoding Base64 or worrying about URL-safe character replacements. After that, the verification function verifies that the signature matches your secret, reassuring you that the token is real.
A Jwt Decoder Online takes a JSON Web Token and extracts its header, payload, and signature so you can read the data inside clearly.
Paste your three-part JWT into the text area, and the tool automatically decodes it into readable JSON sections without any extra clicks.
Yes, enter your secret key, choose HS256, HS384, or HS512 from the dropdown, and click Verify Signature to check authenticity.
Yes, you can upload .txt or .jwt files using the File button or drag and drop directly into the editor area.
The exp claim shows the expiration timestamp. If the current time is past that value, the token is no longer valid.
Click the download icon in the output panel or the Download JSON button in the controls – both save the decoded data as a JSON file.
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