Privacy Policy

Client-side tools

The following tools run entirely in your browser. No data is sent to any server — not ours, not anyone else's:

• Screen Resolution
• Password Security Checker
• User-Agent Parser
• Browser Info

These tools use JavaScript APIs available in your browser (such as window.screen, navigator.userAgent, and the Web Crypto API). All processing happens locally. We cannot see, intercept, or log your input.

Password Security Checker — special note

The Password Security Checker deserves specific mention because of the sensitivity of the data involved. Here is exactly what happens:

• Your password is never transmitted to any server. There are zero network requests triggered by typing in the password field.
• Entropy calculation, strength estimation, crack-time estimates, and common-password detection all run in JavaScript in your browser.
• The common-password list (top 1,000 passwords) is bundled into the page's JavaScript — no server lookup is performed.
• Your password is never logged, stored, or persisted in any form — not in cookies, not in localStorage, not in analytics events.

You can verify this yourself: open your browser's network inspector while using the tool and confirm that no requests are made as you type.

API-backed tools

Some tools require a server because the browser cannot access the data on its own. These tools send the minimum data needed to produce a result:

• What Is My IP — the server reads your IP address from the incoming connection. No additional data is sent.
• Speed Test — your browser downloads and uploads test data to measure throughput. The server discards test data immediately after the transfer completes.
• HTTP Headers — the server reads the HTTP headers your browser sent with the request and returns them to you. Headers are not stored.
• DNS Lookup — the hostname you enter is sent to the server, which performs the DNS query and returns the records. Query hostnames are not stored.

We do not store query history, build user profiles, or correlate requests across tools. Server logs may temporarily record IP addresses and request timestamps for operational purposes (error diagnosis, abuse prevention) and are automatically purged.

Cookies

CheckMySys uses a small number of cookies and local storage entries:

• Theme preference — stored in localStorage to remember your dark/light mode choice across visits.
• Cookie consent — stored in localStorage to remember whether you accepted the cookie consent banner.
• Analytics — we use Vercel Analytics, which is cookieless. It does not set any cookies on your device and does not require consent.
• Advertising cookies — if you accept cookies, Google AdSense may set cookies to serve and measure ads. These cookies are only loaded after you consent.

You can withdraw your cookie consent at any time by clearing your browser's localStorage for this site. On your next visit, the consent banner will reappear.

Analytics

We use Vercel Analytics — a privacy-friendly, cookieless analytics service — to understand how the site is used in aggregate (which tools are popular, approximate visitor location at country level, page performance). It does not set cookies, does not require consent, and cannot identify individual visitors. We also use Vercel Speed Insights to measure Core Web Vitals so we can keep pages fast.

Advertising

CheckMySys is free and supported by ads served through Google AdSense. Ad scripts are loaded only after you accept the cookie consent banner. Ads are placed below the fold on tool pages and never interrupt the tool interface. Google may use cookies to personalize ads based on your browsing history — you can manage ad personalization in your Google Ads Settings.

Third-party services

Beyond the analytics and advertising services described above, we use:

• Vercel — hosts the frontend. Vercel's infrastructure may process your IP address and request metadata as part of serving pages. See Vercel's privacy policy.
• Google Fonts — fonts are self-hosted via next/font and do not make requests to Google's servers at runtime.

Data retention

Client-side tools retain nothing — when you close the tab, the data is gone. API-backed tools do not persist query data. Server logs (IP addresses, timestamps, error details) are retained for operational purposes and automatically purged on a rolling basis.

Children's privacy

CheckMySys is not directed at children under 13. We do not knowingly collect personal information from children. If you believe a child has provided us with personal data, please contact us and we will delete it.

Changes to this policy

We may update this policy as we add new tools or change how the site operates. The "last updated" date at the top reflects the most recent revision.