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§ · free tool
JWT decoder. Read the token, keep the secret.
Paste a JSON Web Token and see its header and payload as readable JSON, with time claims as human dates and an at-a-glance expiry status. Decoded entirely on your device — the signature is never sent anywhere.
A free online tool by Digital HeroesDecoded entirely in this browser — the token, and especially the signature, is never uploaded.
Decoded
header • red
payload • green
Registered claims
Standard time claims interpreted as human dates (your local timezone and UTC).
Signature
NOT verified. This tool only decodes the token — it does not check the signature, because that needs the issuer's secret or public key. Do not trust a decoded token's contents as authentic without verifying the signature on a trusted server.
§ 02 · what you can do
Everything a decoder should do.
Decode instantlyPaste any JWT and the header & payload appear as formatted JSON — no setup, no button to press.
Header & payload side by sideBoth segments shown as indented, readable JSON with the raw token colour-coded into its three parts.
Human-readable claim datesTime claims iat, nbf and exp are converted to local and UTC dates with a relative countdown.
Instant expiry statusA status chip tells you at a glance whether the token is valid, expired, or not yet active.
One-click copyCopy the header or payload JSON straight to your clipboard for use in code or docs.
Private by constructionEverything runs in your browser. The signature is never required and never transmitted.
§ 03 · how to use it
Four steps, no manual.
- Paste your JWT into the box, or click Load sample to try a demo token. A leading “Bearer ” is handled automatically.
- The header and payload decode instantly into formatted JSON, and the raw token is colour-coded into its three segments.
- Check the expiry chip at the top of the result and read the Registered claims table for time claims as human dates.
- Click Copy next to Header or Payload to grab that JSON, or Clear to start over.
§ 04 · faq
Frequently asked questions.
Is the JWT Decoder free?
Yes — completely free for everyone. No sign-up, no account and no usage limits.
Is it private? Is my token uploaded anywhere?
No upload, ever. Decoding runs entirely in your browser on your own device, so the token — and especially the signature — never leaves your computer and nothing is sent to a server.
Does it verify the signature?
No. This tool only decodes the header and payload. Verifying the signature needs the issuer's secret or public key, which should only ever happen on a trusted server — so don't treat a decoded token's contents as authentic until the signature has been verified.
Does it work offline?
Yes — once the page has loaded, decoding works without a connection because all logic runs locally in your browser.
What does the JWT Decoder actually show?
It splits a JSON Web Token into its header and payload and shows both as readable, formatted JSON. It also converts time claims (iat, nbf, exp) to human dates, shows a valid / expired / not-yet-active status chip, and displays the raw signature segment for reference — all in your browser.
Published · Last updated .
