Test maximum localStorage capacity
Test maximum sessionStorage capacity
Test cookies from this domain
Test cross-domain cookie support
Remove all storage data for this site
Export all test results for sharing with support teams
Diagnose browser storage and cookie issues with our comprehensive testing tool. Check localStorage, sessionStorage, IndexedDB, and cookie functionality. Test storage capacity, quota limits, third-party cookie support, and troubleshoot common storage problems. Essential for web developers, technical support, and debugging website issues.
Browser cookies and storage are mechanisms websites use to save data locally on your device.
A single exportable summary of every test above — useful for pasting into a bug report when a site's login or cart isn't persisting and you need to show which storage mechanism is actually broken.
When cookies are disabled, websites cannot maintain sessions, remember login credentials, or save preferences. Most modern websites require cookies for basic functionality. Users who disable all cookies experience broken login systems, repeated privacy notices, and lost shopping carts. Browser privacy settings, extensions, and incognito mode affect cookie behavior. Always enable at least first-party cookies for normal website operation.
Browsers limit storage capacity per domain to prevent abuse. When quota is exceeded, attempts to store data fail with quota errors. This commonly affects applications that cache large files, store offline data, or accumulate data without cleanup. Check quota usage regularly and implement data cleanup strategies. Some browsers allow requesting persistent storage to avoid automatic eviction during storage pressure.
Private browsing modes provide temporary storage that's deleted when closing the window. Some browsers severely limit storage capacity in private mode to prevent tracking. IndexedDB might be completely disabled, and localStorage might have reduced capacity. Applications must gracefully handle storage failures in private mode by providing limited functionality or clear error messages explaining the limitations.
Modern browsers block storage access from third-party contexts (iframes from different domains) by default to prevent tracking. This breaks embedded widgets, social media integrations, and authentication flows relying on third-party storage. Developers must use alternative approaches like postMessage communication, server-side session management, or first-party cookies with appropriate CORS configuration.
Private browsing creates temporary storage that's completely deleted when closing the window. Storage capacity may be reduced compared to normal mode. Some browsers completely disable certain storage types in private mode for security. Websites should detect private mode and either provide limited functionality or clearly explain that features requiring storage won't work. Data stored in private mode never persists to disk.
Storage quotas are automatically determined by browsers based on available disk space and cannot be manually increased. Applications can request persistent storage to prevent automatic eviction, but this doesn't increase total capacity. Free up disk space to increase available storage quota. Some browsers allow users to grant additional permissions for specific sites, but limits still apply.
Most browsers allow clearing site-specific storage through settings. In Chrome, go to Settings > Privacy and security > Cookies and site data > See all site data, then search for the site and click Remove. Firefox has similar options under Options > Privacy & Security > Cookies and Site Data. This tool provides a "Clear All Site Data" button that removes all storage for the current domain instantly.