v4.md is a lightweight IP lookup tool for developers and operations teams. The page displays the IP address of the current request and, based on Cloudflare request metadata, provides details such as country, region, city, latitude/longitude, time zone, ASN, and organization. It is closer to a βscriptable public IP / network diagnostics endpoint,β well suited for quick calls via curl or automation scripts.
It provides both plain-text and JSON interfaces. Plain-text endpoints include the root path, /country, /country-iso, /city, /asn, and /asn-org, returning simple text with a newline by default; JSON can also be requested via Accept: application/json. /json returns complete IP information, while /port/<PORT> can test whether the current request IP is reachable on a specified port. The FAQ also notes that curl -4 or curl -6 can be used to force IPv4 or IPv6 queries.
The main page clearly states that you can run your own instance, with source code and deployment instructions available on GitHub. This is valuable for teams that care about control, privacy, or avoiding instability from third-party services. The page mentions Workers deployment, indicating that the current implementation is related to the Cloudflare Workers ecosystem. However, it does not provide an official SDK; integration is mainly through standard HTTP calls, making it suitable for Shell, CI/CD, monitoring scripts, or any backend language.
The page does not mention paid plans, usage limits, authentication, or an SLA, so it can be viewed as a public free tool. Still, stability should be evaluated independently before relying on it in production. One clear limitation is that Workers deployment does not support using ?ip= to query other IP addresses; it can only return information about the current request IP. As a result, it is not suitable as a general-purpose IP intelligence database or bulk IP geolocation service.
Its strengths are simplicity, clear response formats, curl-friendly usage, JSON support, and self-hosting. Its limitations are a narrow feature scope and a lack of details around rate limits, error codes, privacy policy, and service support; geolocation results are also only approximate. It is a good fit for developers, SREs, and network troubleshooting teams who need to check outbound IPs, verify IPv4/IPv6, script ASN/geolocation lookups, or test port connectivity.
The collected page content does not provide information about availability from mainland China, ICP filing, node locations, or payment options, so access from China is unknown. For stable use, consider self-hosting or evaluating alternatives such as ifconfig.me, ipinfo.io, ipapi.co, and Cloudflare trace.
β This review is compiled from public sources and does not constitute a purchase recommendation. Verify all facts on the vendor's official site. Verify on v4.md official site.
v4.md is an United States Dev Tools provider. TG4G tracks its product information, an overall rating of 6.0/10, and a China-accessibility score of China direct-connect friendly. Click "Visit Official Site" to reach v4.md directly.