Terms of Use

Effective 1 August 2026. Plain language on purpose.

What the service does #

Query a hostname with an IP address embedded in it, get that IP back. Every answer is computed from the query name. There is no database, no account, no signup, and nothing stored about you.

Open-Domain is a-i.st and a-i.sh, operated by an individual as a free service. The source is public and MIT-licensed.

No warranty, no SLA #

The service is provided as is and as available, with no warranty of any kind — express or implied — including merchantability, fitness for a particular purpose, and non-infringement.

• One resolver on one machine. Both suffixes fail together. There is no redundancy.
• No uptime commitment, no support commitment, no response-time commitment.
• The service may change, break, be suspended, or be shut down at any time, without notice.

If your use is production-critical, use something with more machines behind it. nip.io and sslip.io have run this for over a decade.

Limitation of liability #

To the maximum extent permitted by law, the operator is not liable for any damages arising from use of, or inability to use, the service — including lost profits, lost data, service interruption, or any indirect, incidental, special, consequential, or punitive damages, even if advised of the possibility. You use this service at your own risk.

Acceptable use #

Do not use Open-Domain to conduct phishing, fraud, or impersonation; to distribute malware or operate command-and-control infrastructure; to attack, overload, or probe systems you do not own or have permission to test; to send unsolicited bulk email or evade an email or domain block; to evade a lawful takedown, block, or court order; or to disguise the destination of traffic in order to defeat someone’s security controls.

Names are computed, not registered. Nobody owns a name under these suffixes, and creating one grants no rights. A name resolving does not mean the operator has reviewed, endorsed, or has any connection to what is running at that address.

Blocking #

Addresses may be blocked at the operator’s discretion — typically in response to a credible abuse report, but no reason is required and no notice will be given. Blocking is by destination address, so blocking one address blocks every way of spelling it. Blocking a destination is the only enforcement available: the operator does not control, host, or have access to whatever runs at the address you point at.

Rate limiting #

Responses are rate-limited per client address block. Legitimate clients that hit the limit receive a truncated response and can retry over TCP. This is anti-abuse machinery, not a quota you can buy out of.

Reporting abuse #

abuse@open-domain.com — the abuse page explains what to include and what happens next. Security issues: security@open-domain.com.

Privacy #

See the privacy page. Short version: no accounts, no cookies, no tracking, and client IP addresses are truncated before anything is written down.

Changes #

These terms may change. The effective date at the top will change with them, and the history is public in the git repository — every revision is a commit.