It presents the address alongside related network and location details, including country, region, city, postal code, time zone, autonomous system number, and network organization. The displayed location is approximate and based on IP geolocation data supplied through Cloudflare request metadata.

The service is designed for both browser use and command-line access. Its endpoints return plain text by default, while clients can request JSON for structured results. Users can retrieve individual fields, such as country, city, or network provider, or request a complete set of IP information. A port-check endpoint also reports whether a specified port is reachable from the current request IP. The Workers deployment provides information only for the visitor’s own current IP; it does not support lookups for arbitrary addresses. Users can choose IPv4 or IPv6 through their client’s options. Created by mpolden, v4.md is available as open-source software, with source code and deployment instructions on GitHub, and is licensed under the BSD 3-Clause license.