By AndyPublished
jwt.io Alternative: How jwtdecode.app Compares
Side-by-Side Comparison
| Feature | jwtdecode.app | jwt.io |
|---|---|---|
| Decode header and payload | Yes, instantly as you paste | Yes |
| Decoding happens in the browser | Yes | Yes (no network request carried the token in our test) |
| Claim-by-claim view | Yes, with descriptions, relative times and an active/expired badge | Yes, Claims Breakdown tab |
| Verify signatures | HS, RS, PS and ES at 256/384/512 | Yes |
| Public key formats for verification | PEM (SPKI) | SPKI, PKCS #1, X.509 certificate or JWK |
| Create and sign tokens | No | Yes, built-in encoder |
| Library directory | No | Yes, extensive |
| Operated by | Independent, ad-supported (Google AdSense) | Okta (Auth0) |
| Languages | English | English and Japanese |
What Is the Same
Both tools decode a pasted token in the browser. For jwtdecode.app that is the whole architecture: a static site with no backend. For jwt.io we tested it directly: pasting a token into its decoder produced no network request containing the token. Neither tool needs an account to decode or verify, and both show the header and payload as formatted JSON.
Decoding a JWT is also not a secret operation. The header and payload are Base64url-encoded JSON that any tool, or a few lines of code, can read. What differs between tools is what they add around that.
When jwt.io Is the Better Choice
- ·You need to create or sign a token. jwt.io has an encoder. jwtdecode.app deliberately does not generate tokens; for that, use jwt.io or a library such as
jose. - ·You are choosing a JWT library. jwt.io's library directory lists implementations by language along with the algorithms each supports. There is no equivalent here.
- ·Your key is a JWK, a PKCS #1 key or an X.509 certificate. jwt.io accepts those formats directly; jwtdecode.app needs a PEM (SPKI) public key.
- ·You work mainly with Auth0 or Okta. jwt.io links directly into that ecosystem's documentation.
- ·You want Japanese-language documentation. jwt.io is available in Japanese.
When jwtdecode.app Is the Better Choice
- ·You want expiry at a glance. The Claims tab converts
exp,nbfandiatto absolute and relative times, explains each registered claim, and shows a status badge: active, expired, not yet valid or no expiry. - ·You want a vendor-neutral tool. jwtdecode.app is not tied to an identity provider and has no sign-up prompts. It is funded by Google AdSense side-rail ads, which are disclosed on the page and never receive token content.
- ·You are debugging, not just decoding. The site has in-depth guides on debugging rejected tokens, library error messages and algorithms such as ES256 and PS256.
How to Check Any Online Decoder Yourself
Whichever tool you use, you do not have to take its privacy claims on trust. Two checks take under a minute:
- ·Network check: open DevTools → Network, clear the log, paste a token, and look for any request whose URL or body contains it.
- ·Offline check: load the page, switch your machine offline, then paste a token. A local decoder keeps working.
Summary
Both tools decode locally, break down claims and verify signatures. Use jwt.io when you need to generate tokens, verify with a JWK or certificate, or browse libraries. Use jwtdecode.app when you want a vendor-neutral decoder with expiry status at a glance and debugging guides alongside it.