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.
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
expclaim (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.
Added Jul 5, 2025
🔄 Workflow Suggestion
Try combining multiple tools for a complete workflow. For example: Notepad → Text Encryption → Save to Cloud or Date Calculator → Calendar → Countdown Timer
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