JWT Encoder
Generate signed JSON Web Tokens with HS256, HS384, or HS512. Set custom header and payload, provide a secret, and copy the encoded JWT.
JWT Encoder
How it works
1. Base64URL-encode the header JSON and payload JSON separately.
2. Concatenate them as header.payload.
3. Sign that string using HMAC with your chosen SHA algorithm and secret.
4. Base64URL-encode the signature and append as header.payload.signature.
⚠ For development and testing only. Never expose real secrets in a browser tool.
How JWT signing works
HMAC-based JWT signing combines the Base64url-encoded header and payload with a secret key to produce a signature. The three parts are joined with dots to form the final token.
Security warning
Never use real production secrets in browser-based tools. This encoder is intended for development, testing, and learning only.
Why use JWT Encoder online?
JWT Encoder in the browser saves context switching: no CLI install, no fragile one-liners, and instant feedback for teammates who do not live in the terminal. It is ideal for debugging, demos, and quick checks during code review.
Tips for best results
Work with a sample payload first, then paste production data. Keep privacy in mind: prefer local browser processing for secrets, tokens, and customer data. Bookmark this page for faster access next time.
How to use
- Choose an algorithm (HS256, HS384, or HS512).
- Edit the payload JSON — add any claims you need.
- Enter a secret key.
- Click Generate JWT and copy the result.
- Review the output and use Copy to paste into your editor, ticket, or chat.
- Need another utility? Scroll to Related Tools below for JWT Encoder companions on skybin.io.
- For a deeper walkthrough, read the linked Skybin blog article at the bottom of this page.
Online tool vs terminal
| Terminal / CLI | This tool |
|---|---|
| Install CLI tools or write a one-off script | Open the tool in your browser — no install |
| Look up flags in man pages or Stack Overflow | Paste input or upload files where supported |
| Repeat for each file format or edge case | Get instant visual feedback and copy buttons |
Signing runs in your browser using the Web Crypto API — no data is sent to any server.
Frequently Asked Questions
- What does JWT Encoder do?
- Generate signed JSON Web Tokens with HS256, HS384, or HS512. Set custom header and payload, provide a secret, and copy the encoded JWT.
- Which algorithms are supported?
- HS256, HS384, and HS512 (HMAC-SHA). RS256 and other asymmetric algorithms are not supported in this browser tool.
- Is this safe to use with production secrets?
- No. Never enter production secrets into any browser tool. Use this for development and testing only.
- Is this tool free to use?
- Yes. All Skybin developer tools are free with no account, API key, or usage limits.
- Does my data get sent to a server?
- No. Processing runs in your browser whenever possible. Sensitive input never leaves your device unless a tool explicitly fetches a URL you provide (e.g. OG Validator).
- Can I use this on mobile?
- Yes. The tools work in modern mobile browsers, though a desktop screen is easier for large JSON or PDF workflows.
- How is this different from desktop apps?
- There is nothing to install or update. Open a bookmarked URL and start working — ideal for quick tasks during development or support calls.
- Are there keyboard shortcuts?
- Most tools support standard paste (Ctrl+V / Cmd+V) and select-all in text areas. Copy buttons provide one-click output.
- Does Skybin store my history?
- No. We do not log tool inputs or outputs. Refreshing the page clears in-memory state unless the tool encodes state in the URL.