Best jwt.io Alternative — Stax JWT Decoder (2026)

Feature	jwt.io	StaxFree
Decode header + payload	✅	✅
Verify signature (enter the secret)	✅	❌
Encode / build a token	✅	❌
Expiry badge and issued-at time	Claims breakdown view (shown as raw numbers on the page I checked)	Expiry badge and issued-at time
Where decoding runs	Not stated on its homepage	In your browser
Base64, hash and regex tools on the same site	Not checked	✅

Feature

jwt.io

StaxFree

Decode header + payload

✅

Verify signature (enter the secret)

✅

❌

Encode / build a token

✅

❌

Expiry badge and issued-at time

Claims breakdown view (shown as raw numbers on the page I checked)

Expiry badge and issued-at time

Where decoding runs

Not stated on its homepage

In your browser

Base64, hash and regex tools on the same site

Not checked

✅

jwt.io vs Stax JWT Decoder

jwt.io is the best-known JWT debugger. Its homepage offers a decoder, an encoder and signature verification (you enter the secret). Stax JWT Decoder decodes the header and payload in your browser and sits next to the Base64 encoder, hash generator, regex tester and the rest of the developer toolkit. This page is an independent comparison, last checked against jwt.io's homepage on 15 October 2026; Stax is not affiliated with jwt.io. jwt.io's homepage does not say where it decodes tokens, so check its privacy notice and the Network tab before pasting a live token.

What makes JWT debugging different from other token formats

JWTs, standardized in RFC 7519, are three Base64URL-encoded parts joined by dots. The first two parts are JSON (header and payload). The third is the signature, structured per the JSON Web Signature format in RFC 7515. Decoding the first two is just Base64URL decoding + JSON.parse — no secret needed. That is why a decoder can run entirely in the browser without uploading anything: the cryptography only matters for verification, not decoding.

Common use cases for a JWT decoder

Backend engineers paste tokens from Authorization headers during debugging to verify that the correct roles, user IDs, and expiry are embedded in the payload. Frontend developers inspect tokens stored in localStorage or cookies to diagnose authentication bugs without spinning up a debugger. Security engineers review token claims during penetration tests to confirm that sensitive data is not being leaked in unencrypted payloads — a common misconfiguration in early-stage applications.

JWT security tips

Never put sensitive data (passwords, payment info, SSNs) in a JWT payload — the payload is only Base64-encoded, not encrypted. Anyone who holds the token can decode it without a key. If you need confidentiality, use a JWE (JSON Web Encryption) token instead of a plain JWT. Always set a short exp (expiry) claim — 15–60 minutes for access tokens, 7–30 days for refresh tokens. Validate the iss (issuer) and aud (audience) claims server-side to prevent cross-service token reuse attacks.

Who uses a JWT decoder regularly

Node.js and Go backend engineers inspect tokens when debugging auth middleware. Mobile developers check token expiry to diagnose silent logout bugs. DevOps engineers review service-to-service tokens in microservice architectures. Security reviewers paste tokens from bug bounty programs to check for information disclosure. Developers integrating with OAuth 2.0 providers like Google, GitHub, or Okta inspect id_token claims to understand what fields are returned by each provider's OIDC implementation.

Frequently asked questions

Is it safe to paste production tokens into a JWT debugger?

Only if the tool decodes in your browser. Stax JWT Decoder does, and you can verify it in the Network tab. jwt.io's homepage does not say where it decodes tokens, so read its privacy notice and check the Network tab before pasting a production token into it or any other online debugger. Many teams avoid pasting live tokens anywhere and use a local tool.

Why use Stax instead of jwt.io?

Mainly for the toolkit around it: when you also need to decode Base64, generate a hash or test a regex, it is all one site, and Stax decodes the token in your browser and never records what you paste. Like most sites it counts page visits with analytics, which its privacy page describes. jwt.io does more with the token itself: it verifies signatures and has an encoder, which Stax does not.

Can Stax verify JWT signatures?

No. Stax decodes the header and payload only and does not verify signatures. jwt.io can verify a signature if you enter the secret. For production verification use a backend library (jose for Node, PyJWT for Python) where the key stays on your server.

Which JWT algorithms are supported?

All standard ones for decoding — HS256, HS384, HS512, RS256, RS384, RS512, ES256, ES384, ES512, PS256, etc. The algorithm is read from the header; we just decode the parts. Decoding works for any valid JWT regardless of the signing algorithm.

Does Stax show expiry warnings?

Partly. If the payload has an exp claim, Stax shows the expiry as a readable date with an Expired or Valid badge, and if it has an iat claim it shows the issued-at time. Other time claims such as nbf appear in the payload as raw numbers.

jwt.io Alternative