Cookie Security Checker
Check if your cookies follow security best practices with our free cookie security checker. Paste any Set-Cookie header value and get a comprehensive analysis of every security attribute including Secure, HttpOnly, SameSite, Expires, Max-Age, Path, and Domain. Each cookie receives a security score (0-100) with specific warnings and actionable recommendations for insecure configurations - all processed locally in your browser with no signup required.
Paste any Set-Cookie header value and get a comprehensive security analysis. Our cookie security checker validates Secure, HttpOnly, SameSite, Expires, Max-Age, Path, and Domain attributes against security best practices. All analysis is performed locally in your browser. Press ⌘+↵ to analyze.
Enter one or more Set-Cookie headers separated by commas. Supports name=value pairs with attributes like Secure, HttpOnly, SameSite, Expires, Max-Age, Path, Domain, and more.
Why Use Our Cookie Security Checker?
Comprehensive Cookie Security Analysis
Our cookie security checker evaluates every Set-Cookie attribute against security best practices. It checks Secure flag, HttpOnly flag, SameSite policy, Expires/Max-Age validity, Path and Domain scope, providing a clear pass/fail verdict with detailed explanations and actionable recommendations.
Multi-Cookie Batch Analysis
Analyze multiple Set-Cookie headers at once by separating them with commas. The cookie security checker parses each cookie independently, showing individual security scores and recommendations for every cookie. Perfect for auditing full HTTP response headers.
Secure & Private Browser-Based Processing
Your cookie values never leave your device. All analysis is performed locally in your browser using JavaScript. No data is sent to any server, making this the most private cookie security checker available online.
Cookie Security Checker Online - No Installation
Use our free cookie security checker directly in your browser with no downloads, no plugins, and no account required. Includes preset examples showing secure and insecure cookie configurations, a quick reference guide, and smart detection of missing or misconfigured security attributes.
Common Use Cases for Cookie Security Checker
Web Application Security Audit
Security auditors use cookie security checkers to verify that session cookies, authentication tokens, and other sensitive cookies have the correct security attributes. Validate that Secure, HttpOnly, and SameSite are properly configured across all cookies set by your application.
Cookie Configuration Debugging
When browser cookie warnings appear in developer tools, use the cookie security checker to quickly identify misconfigured attributes. Check for missing SameSite values, Secure flag violations on HTTP pages, or improperly formatted Expires dates that cause cookies to be rejected.
Server Response Header Review
Developers can paste raw Set-Cookie headers from server responses into the cookie security checker to verify their backend is generating properly configured cookies. Review Path and Domain attributes to ensure cookies are scoped correctly for your application architecture.
Third-Party Cookie Integration Testing
When integrating third-party services that set cookies (analytics, advertising, embedded content), use the cookie security checker to verify that third-party cookies have SameSite=None with Secure flag, proper Domain scoping, and appropriate expiration policies.
Security Policy Compliance
Compliance teams can use the cookie security checker to verify that cookies meet organizational security policies and regulatory requirements. Check for adherence to OWASP cookie security guidelines, GDPR consent cookie requirements, and internal security standards.
Developer Education & Training
Train developers on cookie security best practices by demonstrating how different attribute configurations affect cookie security. Show the difference between a secure cookie configuration and an insecure one, and explain why each security attribute matters.
Understanding Cookie Security
What are HTTP Cookies and Why Security Matters?
HTTP cookies are small pieces of data sent from a web server to a browser, which stores them and sends them back with subsequent requests. Cookies enable session management, personalization, and tracking - but they also introduce significant security risks if not properly configured. A Set-Cookie header can include several security attributes (Secure, HttpOnly, SameSite) that protect against common attacks like session hijacking, cross-site scripting (XSS), and cross-site request forgery (CSRF). Our cookie security checker evaluates each of these attributes against current best practices.
How Our Cookie Security Checker Works
- Paste Set-Cookie Headers: Enter one or more Set-Cookie header values into the input field. Separate multiple cookies with commas. The tool supports the full cookie specification including quoted values and complex attribute combinations.
- Parse & Validate: The tool parses each cookie using a robust parser that handles quoted strings, special characters, and all standard cookie attributes. Each attribute is validated against security best practices and assigned a pass/fail status.
- Score & Recommendations: Each cookie receives a security score (0-100) based on its attribute configuration. Missing or misconfigured attributes generate warnings with specific, actionable recommendations for improving cookie security.
Cookie Security Attributes Explained
- Secure: Ensures the cookie is only sent over HTTPS connections. Without this flag, cookies can be intercepted over unencrypted HTTP connections via man-in-the-middle attacks. Essential for all cookies containing sensitive data.
- HttpOnly: Prevents JavaScript from accessing the cookie via
document.cookie. This is your primary defense against session theft via XSS attacks. - SameSite: Controls when the cookie is sent with cross-site requests.
Strictoffers the strongest CSRF protection.Lax(the modern browser default) balances security and usability.Noneallows all cross-site requests but requires Secure. - Expires / Max-Age:Define the cookie's lifetime. Session cookies (no expiration) are deleted when the browser closes. Persistent cookies with very long lifetimes increase the window of vulnerability if the cookie is stolen.
Privacy, Security & Availability
Our cookie security checker processes everything entirely in your browser. The Set-Cookie header values you paste never leave your device - no data is uploaded, stored, or logged on any server. This complete privacy ensures you can safely analyze cookies from any environment, including production systems with sensitive session tokens. The tool is 100% free with no signup, no usage limits, and no tracking. Use it as many times as you need, for as many cookies as you need, completely free forever. No installation or downloads are required - just open your browser and start checking your cookie security.
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Frequently Asked Questions About Cookie Security Checker
A cookie security checker analyzes Set-Cookie HTTP headers to evaluate whether cookies are configured following security best practices. It validates attributes like Secure, HttpOnly, SameSite, Expires, Max-Age, Path, and Domain, providing a security score and specific recommendations for improving cookie security configuration.
The Secure flag tells the browser to only send the cookie over HTTPS connections. Without this flag, cookies can be transmitted over unencrypted HTTP connections, making them vulnerable to interception by attackers on the same network (man-in-the-middle attacks). Every cookie that contains sensitive data - including all session and authentication cookies - MUST have the Secure flag set.
SameSite=Strict prevents the cookie from being sent with ANY cross-site request, including when a user clicks a link from another site to your site. This provides the strongest CSRF protection but can break user experience for incoming links. SameSite=Lax (the modern browser default) allows the cookie to be sent with top-level navigations (clicking a link) but not with subresource requests or form submissions. Lax balances security and usability for most applications.
The HttpOnly flag makes the cookie inaccessible to JavaScript running in the browser via document.cookie. This is a critical defense against Cross-Site Scripting (XSS) attacks - even if an attacker manages to inject malicious scripts into your page, HttpOnly cookies cannot be read or stolen. Session cookies, authentication tokens, and CSRF tokens should always use HttpOnly.
No. Our cookie security checker processes everything entirely in your browser using JavaScript. The Set-Cookie header values you paste never leave your device. We do not store, log, or transmit your cookie data to any server. Your analysis is completely private.
Modern browsers (Chrome, Firefox, Edge) default to SameSite=Lax for cookies without a SameSite attribute. This means the cookie will be sent with top-level navigations from other sites but not with cross-site subresource requests. Older browsers may treat missing SameSite as None, which is less secure. Always explicitly set SameSite to Strict, Lax, or None to ensure consistent behavior across all browsers.
The ideal cookie lifetime depends on the cookie's purpose. Session cookies (no expiration) provide the best security for authentication since they expire when the browser closes. For persistent cookies, keep the lifetime as short as practical - 24 hours for session tokens, up to 30 days for "remember me" functionality, and never more than 1 year. Very long-lived cookies increase the risk window if the cookie is ever compromised.