JWT Decoder / Encoder

Paste any JSON Web Token to instantly decode its header & payload, verify the signature (HS256) with your secret, or craft a brand-new token right in your browser – nothing is sent to a server.

🔐 JWT Token

📄 Header (JSON)

🧾 Payload (JSON)

🔑 Secret (HS256)

Decode & Inspect

View token header & payload with syntax-highlighted JSON and claim expiry countdown – perfect for quick debugging.

Encode & Sign

Build a header & payload, supply a secret, and generate a HS256-signed JWT in one click.

Verify Signature

Confirm a token's integrity by validating its signature against your secret key – get instant pass/fail feedback.

Why use this JWT tool?

Client-side only: All encoding/decoding happens in your browser – your tokens and secrets never leave your device.
Live expiry countdown: See how long until a token expires based on the exp claim (if present).
Instant validation: Invalid structure or malformed Base64 parts are detected and surfaced immediately.
Copy & share: Quick copy buttons on every section let you share tokens or JSON fragments with teammates.
Open-source & auditable: Explore the code on GitHub and verify there's no hidden network requests.

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