JWT Expiration Checker
Check JWT token expiration and decode JWT payload
Token Status
Header
Payload
Signature
Note: This tool only decodes JWT tokens. Signature verification requires the secret key and should be done on the server side.
All JWT decoding and checking is done locally in your browser. Your tokens never leave your device.
About JWT Expiration Checker
This free online JWT (JSON Web Token) expiration checker helps you quickly verify if a JWT token is expired, decode its contents, and validate its structure. Perfect for developers working with authentication systems, APIs, and secure token-based applications.
All JWT processing is done locally in your browser - your tokens never leave your device, ensuring complete security for sensitive authentication data.
The tool decodes the JWT header and payload, displays expiration information, and shows how much time remains until expiration or how long ago the token expired.
How to Use
- Paste your JWT token in the input area (the token usually starts with "eyJ...")
- Click "Check Expiration" to verify if the token is expired and see expiration details
- Click "Decode JWT" to view the decoded header and payload
- Review the results:
- Token Status: Shows if token is valid, expired, or not yet valid
- Expiration Time: When the token expires (if "exp" claim exists)
- Time Remaining: How long until expiration or how long ago it expired
- Decoded Data: View header (algorithm, type) and payload (claims)
- Copy decoded data using the copy buttons for header or payload
Key Terms & Concepts
JWT (JSON Web Token)
A compact, URL-safe token format used for securely transmitting information between parties. JWTs are commonly used for authentication and authorization in modern web applications.
JWT Structure
A JWT consists of three parts separated by dots (.): Header.Payload.Signature. Each part is Base64URL encoded.
Header
Contains metadata about the token, typically the signing algorithm (alg) and token type (typ).
Payload
Contains the claims - statements about the user and additional data. Common claims include exp (expiration), iat (issued at), sub (subject), and custom claims.
Signature
Created by encoding the header and payload, then signing with a secret key. This tool only decodes but does not verify signatures.
exp Claim
The expiration time claim (exp) is a Unix timestamp indicating when the token expires. After this time, the token should not be accepted.
iat Claim
The issued at claim (iat) is a Unix timestamp indicating when the token was created.
nbf Claim
The not before claim (nbf) is a Unix timestamp indicating when the token becomes valid. The token should not be accepted before this time.
Common Use Cases
- API Development: Verify JWT tokens during development and testing of authentication systems
- Debugging Authentication: Check why a token might be rejected (expired, not yet valid, malformed)
- Token Inspection: Quickly view claims and expiration times without writing code
- Security Testing: Analyze JWT tokens during security audits or penetration testing
- Development Testing: Verify token expiration logic in your applications
- Token Lifecycle Management: Monitor when tokens will expire for refresh logic
- Learning & Education: Understand JWT structure and how tokens work
Examples
Example 1: Valid Token
A JWT token with future expiration:
- Status: Valid Token ✓
- Time Remaining: 2 hours 45 minutes
- Header: {"alg":"HS256","typ":"JWT"}
- Payload: {"sub":"1234567890","name":"John Doe","exp":1735891200}
Example 2: Expired Token
A JWT token that has already expired:
- Status: Token Expired ✗
- Expired: 3 days 5 hours ago
- Expiration Time: 2024-12-25 10:30:00 UTC
Example 3: Token Without Expiration
A JWT token that doesn't have an exp claim:
- Status: No Expiration Set
- Note: Token does not expire automatically
- Warning: Consider adding expiration for security
Important Notes
⚠️ Signature Verification: This tool only decodes JWT tokens. It does not verify the signature. Always verify JWT signatures on your server before trusting the token contents.
🔒 Security: All decoding happens in your browser. Your JWT tokens never leave your device. However, be cautious when sharing decoded token contents as they may contain sensitive information.
📅 Expiration Checking: Expiration checking is based on the "exp" claim in the token. If your token doesn't have an "exp" claim, expiration cannot be determined.
🕐 Time Synchronization: Expiration times are checked against your device's clock. Ensure your system time is accurate for correct results.
🔐 Token Handling: Never share your JWT tokens publicly or paste them into untrusted tools. This tool is safe (client-side only), but exercise caution with production tokens.
✅ Best Practices: Always set expiration times on JWTs for security. Short-lived tokens (minutes to hours) are more secure than long-lived tokens.
Frequently Asked Questions
What is a JWT token?
JWT (JSON Web Token) is a compact, URL-safe token format used for securely transmitting information between parties. JWTs are commonly used for authentication and authorization in modern web applications. A JWT consists of three parts: header, payload, and signature, separated by dots.
Is my JWT token sent to a server?
No, all JWT decoding and expiration checking happens entirely in your browser. Your tokens never leave your device, making this tool completely safe for production and sensitive authentication tokens.
Does this tool verify JWT signatures?
No, this tool only decodes JWT tokens to read their contents and check expiration. It does not verify cryptographic signatures. Always verify JWT signatures on your server before trusting token contents in production applications.
What does "Token Expired" mean?
Token Expired means the "exp" (expiration) claim in the JWT has passed the current time. Expired tokens should not be accepted by servers and typically require the user to re-authenticate or refresh the token.
What if my JWT doesn't have an expiration?
If a JWT doesn't contain an "exp" claim, it technically doesn't expire automatically. However, this is generally not recommended for security reasons. Most authentication systems should set expiration times on JWTs.
How do I read the decoded JWT data?
After decoding, the tool displays the header (containing algorithm and token type) and payload (containing claims like user ID, expiration, issued at, and custom data). All data is displayed in JSON format for easy reading.
Why is my valid token showing as expired?
Check your device's system time. Expiration checking is based on your local clock. If your system time is incorrect, it may show valid tokens as expired or vice versa. Also verify the token was issued with the correct expiration time.
Can I decode tokens from any application?
Yes, this tool can decode any standard JWT token regardless of which application or framework created it. JWTs follow a standardized format (RFC 7519) that works across all platforms and programming languages.
What are the three parts of a JWT?
A JWT has three Base64URL-encoded parts separated by dots: Header (algorithm and type), Payload (claims and data), and Signature (cryptographic signature for verification). The format is: xxxxx.yyyyy.zzzzz
Is it safe to use this tool with production tokens?
Yes, since all processing happens locally in your browser and tokens never leave your device. However, always be cautious about where you paste sensitive tokens. Avoid sharing decoded token contents that may contain confidential information.
What is the difference between exp, iat, and nbf claims?
exp (expiration time) is when the token expires. iat (issued at) is when the token was created. nbf (not before) is when the token becomes valid. All three use Unix timestamps (seconds since January 1, 1970).
How often should JWT tokens expire?
For security, access tokens should typically expire in 15 minutes to 1 hour. Refresh tokens can last longer (days to weeks). The ideal expiration time depends on your security requirements and user experience needs.