ipv6.fail
ipv6.fail requires JavaScript to run the test matrix from your
browser.
If you've turned JavaScript off, you can still probe each endpoint
directly:
curl https://v4.ipv6.fail/api/probe
curl https://v6.ipv6.fail/api/probe
curl https://ds.ipv6.fail/api/probe
curl https://mtu.ipv6.fail/api/probe
curl https://mtu4.ipv6.fail/api/probe
curl https://mtu6.ipv6.fail/api/probe
Each returns a JSON object describing your connection on that family.
For the leak-check verdict, POST to
https://api.ipv6.fail/api/leak-check with
{"ipv4": "...", "ipv6": "..."}.