NAT Checker - Free Online NAT Type Detection Tool

Free, fast, accurate NAT check for developers and gamers on PS5, Xbox, Switch, and PC. Understand network status and improve play.

NAT Checker - Free Online NAT Type Detection Tool: In beta, open to join. Get it at natchecker.com.

NAT Checker is a browser-based network diagnostic tool for gamers and developers who want to know how their connection handles peer-to-peer traffic. It uses STUN to discover the public IPv4 address and mapped UDP port, then runs server-assisted WebRTC and ICE connectivity checks to classify the path as NAT 1 to 4 following RFC 3489. Separate checks report a public IPv6 address and external IPv6 connectivity, along with blocked, timeout and error outcomes. Platform guides cover PS5, Xbox Series X/S, Nintendo Switch, Windows PC and router settings. The tool is free and needs no setup or sign-up.