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Free JWT Decoder & Verifier - Decode, Inspect & Verify JSON Web Tokens
Decode JWT headers and payloads instantly, then verify signatures using HMAC (HS256/384/512), RSA (RS256/384/512), or ECDSA (ES256/384/512). All processing is 100% client-side.
100% Free
Privacy Focused
Instant Results
Works Everywhere
JWT Decoder
Decode and verify JWT tokens. Inspect headers, payloads, and verify signatures using HMAC (HS256/384/512), RSA (RS256/384/512), and ECDSA (ES256/384/512).
Encoded JWT
Header
Payload
Signature
Raw base64url encoded signature. Go to Verify Signature tab to validate it cryptographically.
Encoded JWT
About This Tool
What is JWT Decoder?
Our JWT Decoder & Verifier is the most complete browser-based JWT tool available. It decodes any JSON Web Token in real time, showing you a color-coded token visual, a parsed claims view with human-readable descriptions, and a raw JSON view with syntax highlighting — all without sending your token to any server.
Beyond decoding, the Verify Signature tab lets you cryptographically verify a token's signature using HMAC (HS256, HS384, HS512) with a plain text or Base64-encoded secret, RSA (RS256, RS384, RS512) with a PEM public key, or ECDSA (ES256, ES384, ES512) with a PEM public key. This uses the browser's native Web Crypto API — no external libraries, no server calls, no privacy risk.
Every standard JWT claim is annotated with a friendly label and description: standard registered claims like iss, sub, aud, exp, nbf, iat, and jti; OpenID Connect claims like name, email, email_verified, and locale; and OAuth 2.0 claims like scope, azp, and nonce. Timestamp claims (exp, nbf, iat) show the absolute date and a relative countdown ("expires in 2h 30m" or "expired 3 days ago").
All decoding and verification happens locally in your browser. Your tokens never leave your device.
Features
Powerful Features
Everything you need in one amazing tool
Live Decoding
Decode JWT tokens as you type. Header, payload, and signature displayed the instant you paste.
Parsed Claims View
Every claim shown with its label, description, and for timestamps an absolute date plus live relative countdown.
Signature Verification
Verify signatures with HMAC (HS256/384/512), RSA (RS256/384/512), and ECDSA (ES256/384/512) using the Web Crypto API.
Expiry & Time Cards
Instant validity bar shows expired/valid/no-exp state with time remaining. iat, nbf, and exp shown as summary cards.
Syntax-Highlighted JSON
Toggle between Parsed and Raw JSON views. Raw view includes color-coded syntax highlighting for keys, strings, numbers, and booleans.
100% Client-Side
All decoding and signature verification happens in your browser via Web Crypto. Your tokens never leave your device.
Simple Process
How It Works
Get started in 4 easy steps
1
Paste JWT Token
Paste your JWT into the Decode tab. The token is decoded instantly as you type.
2
Inspect Claims
View all claims in Parsed mode with labels and descriptions, or switch to Raw JSON with syntax highlighting.
3
Check Expiry
The validity bar and time cards show immediately if the token is expired, valid, or not yet active.
4
Verify Signature
Switch to Verify Signature tab, select the algorithm, enter your secret or PEM public key, and confirm authenticity.
Why Us
Why Choose Our JWT Decoder?
Stand out from the competition
Instant Results
Decode in milliseconds with no loading or delays. Results appear as you type.
Real Signature Verification
Go beyond decoding — actually verify HMAC, RSA, and ECDSA signatures without leaving the browser.
Claim Education
Every claim is annotated with a plain-English description so you and your team understand the token at a glance.
100% Private
Client-side only using the Web Crypto API. Your production tokens stay on your device, always.
Debug Faster
Identify expired tokens, wrong claims, or mismatched signatures in seconds. Fix auth bugs efficiently.
Unlimited Use
No registration, no limits. Decode and verify unlimited tokens completely free.
Use Cases
Perfect For
See how others are using this tool
Authentication Debugging
Debug login issues by inspecting token claims. Check if user ID, email, or roles are correct.
API Development
Verify API tokens contain correct claims. Test authentication flows and confirm token generation is correct.
Security Audits
Confirm tokens use expected signing algorithms and don't expose sensitive data in their payloads.
Expiration Testing
Check token expiration times. Test refresh token logic and session timeout handling.
Learning & Education
Understand JWT structure, claims, and cryptographic signing. Learn how modern authentication works.
Signature Validation
Verify tokens issued by your identity provider using RSA or ECDSA public keys before trusting them.
Frequently Asked Questions
Everything you need to know about JWT Decoder
JWT (JSON Web Token) is a compact, URL-safe token format used for securely transmitting information between parties. It consists of three Base64URL-encoded parts separated by dots: header (algorithm and token type), payload (claims/user data), and signature (cryptographic verification). JWTs are commonly used for authentication in modern web applications and APIs.
Yes — our tool uses the browser's native Web Crypto API to verify signatures without any server calls or third-party libraries. It supports HMAC (HS256/384/512) with a secret key, and RSA (RS256/384/512) and ECDSA (ES256/384/512) with a PEM-encoded public key. Your token and key never leave your browser.
Yes, absolutely. All decoding and verification happens entirely in your browser — no server communication. Your tokens never leave your device, making it completely safe to use with production JWTs. Be cautious about sharing decoded token contents with others as they may contain sensitive user information.
Decoding simply reads the Base64URL-encoded contents of the header and payload — anyone can do this without a key. Verification checks the cryptographic signature to confirm the token was signed by the expected party and hasn't been tampered with. Use the Verify Signature tab to actually validate the token's integrity.
Common claims include iat (issued at), exp (expiration), sub (subject/user ID), aud (audience), iss (issuer), and nbf (not before). OpenID Connect adds name, email, email_verified, and locale. OAuth 2.0 adds scope, azp (authorized party), and nonce. Our Parsed view shows a friendly label and description for all of these.
JWTs have an expiration time (exp claim) for security. Once expired, the token is no longer valid and servers should reject it. This forces users to obtain new tokens periodically. If you see "Expired," you need to refresh the token via your application's refresh mechanism or log in again.
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