If you want to test icmp RTT (ping) metrics from different global locations to your server, you can use https://ping.as services (still in beta but quite usable).
It uses websocket and react on client side to give near realtime experience from browser.
Both of the IPv4 and IPv6 supported. There are a lot of alternatives for online IPv4 ping tests but IPv6 deployments increasing day to day, so good IPv6 support is a must for any type of test methodologies.
Ping.as also has following features:
- Twamp and Twamp Light Test
- Dns Lookup
- Ip Calculator
- Whois Lookup