Terms of Service

Short version:The tools on sysadmintools.dev are free to use for legitimate purposes. Don't use them to scan systems you don't own or to harass anyone. Information returned by the tools is provided "as is" without warranty. If you break these terms or the law using our tooling, that's on you.

The legalese below spells out what that means in detail. By using the site you agree to it.

1. Acceptance of terms

By accessing or using sysadmintools.dev (the "Site"), you agree to be bound by these Terms of Service. If you do not agree, do not use the Site.

2. What the Site is

Sysadmintools.dev is a free, no-login collection of network and security utilities aimed at IT professionals. The Site runs DNS lookups, computes subnet math, displays your public IP, inspects HTTP and TLS headers, performs WHOIS lookups, and provides other similar read-only utilities (collectively, the "Tools").

The Tools are intended for diagnostics on infrastructure you own or are explicitly authorized to test. The Site is provided for personal and professional use; commercial redistribution of output requires attribution.

3. Eligibility and account requirements

There is no account system. You don't need to register, you don't need to provide an email, and we don't ask for any identifying information. By using the Site you confirm that you are at least 13 years old and that the laws of your jurisdiction allow you to use the Tools.

4. Acceptable use

You agree not to use the Site to:

• Scan, probe, or otherwise interact with systems, networks, or domains you do not own or have documented written authorization to test.
• Conduct denial-of-service attacks, brute-force enumeration, or any activity intended to degrade, disable, or overwhelm a target.
• Harvest personal data about any individual from the Tools' output (for example, by resolving an IP address to a person and acting on that information).
• Bypass, circumvent, or attempt to circumvent any rate limit, access control, or security measure on the Site or any third party referenced by the Site.
• Use automated scraping to mirror the Tools' UI in a way that degrades service for other users.
• Reverse-engineer the Site for the purpose of building a competing product.
• Violate any applicable local, state, national, or international law or regulation.

We may block IP ranges or geographic regions we believe are generating abusive traffic. Abuse reports go to [email protected].

5. No warranty

The Site and the Tools are provided "as is" and"as available" without warranty of any kind, express or implied, including but not limited to warranties of merchantability, fitness for a particular purpose, accuracy, or non-infringement.

We do not warrant that:

• The Tools will be uninterrupted, timely, secure, or error-free.
• The results produced by the Tools (DNS records, WHOIS data, header inspection results, geolocation, etc.) are accurate or current.
• Defects will be corrected.
• The Site or the servers that make it available are free of viruses or other harmful components.

Network data is provided by third parties (public DNS resolvers, IP geolocation providers, registry operators, certificate authorities). We do not control those sources and we do not guarantee the integrity of their responses.

6. Limitation of liability

To the maximum extent permitted by applicable law, in no event shall the operator of sysadmintools.dev, its contributors, or its affiliates be liable for any indirect, incidental, special, consequential, or punitive damages (including, without limitation, loss of data, loss of business opportunity, or loss of reputation) arising out of or in connection with your use of, or inability to use, the Site or the Tools, even if advised of the possibility of such damages.

In jurisdictions that do not allow the exclusion of certain damages, our liability is limited to the maximum extent permitted by law.

7. Indemnification

You agree to indemnify and hold harmless the operator of sysadmintools.dev from any claim, demand, loss, liability, or expense (including reasonable attorneys' fees) arising out of your use of the Site, your violation of these Terms, or your violation of any third party's rights.

8. Third-party services

The Tools rely on third-party services for data, including:

• ip-api.comfor IP geolocation lookups in the "What Is My IP" tool.
• Public DNS resolvers used to answer queries in the DNS tool.
• Domain registrars and WHOIS servers queried for domain registration data.
• Google AdSense for advertising on the Site (see our Privacy Policy).
• Optional: Plausible Analytics or Cloudflare Web Analytics for privacy-friendly aggregate traffic measurement. These do not set cookies and do not track you across sites.

Your use of those third-party services is governed by their own terms and policies. We are not responsible for their practices.

9. Intellectual property

The Site's source code (Next.js, TypeScript, CSS, layout, copy) is the property of the operator. You may not reproduce, distribute, modify, or create derivative works of the Site without permission. The Tools themselves return data that belongs to its respective owners (registrars, DNS operators, etc.) — those data are not "our" content.

If you want to reference or quote the Site (for example, in a blog post or a talk), that's fine. Please attribute and link back.

10. Changes to the Site

We may add, remove, modify, or discontinue any Tool or feature at any time, with or without notice. We are not liable for any impact such changes may have on workflows or integrations you have built around the Site.

11. Changes to these terms

We may update these Terms occasionally. When we do, we'll change the "Last updated" date below. Material changes will be reflected in a clear notice on the homepage; continued use after a change means you accept the updated Terms.

12. Governing law

These Terms are governed by the laws of the State of New York, United States, without regard to its conflict-of-laws principles. Any dispute arising from these Terms or your use of the Site shall be resolved exclusively in the state and federal courts located in New York County, New York.

13. Severability

If any provision of these Terms is held to be unenforceable, the remaining provisions will continue in effect.

14. Contact

Questions about these Terms? Open an issue on GitHub or email [email protected].

Last updated: July 2026.