Yes — growthlook.app has IPv6.

Has both IPv4 (A) and IPv6 (AAAA) addresses.

IPv6 readiness

Works over IPv6, with one gap: its mail servers lack IPv6.

Website over IPv6 growthlook.app has 2 IPv6 addresses and answers on every one we tested. ✓ 2606:4700:3031::ac43:cbd3 answers · 443✓ 2606:4700:3030::6815:5ab9 answers · 443	yes
www over IPv6 www.growthlook.app has 2 IPv6 addresses and answers on every one we tested. ✓ 2606:4700:3031::ac43:cbd3 answers · 443✓ 2606:4700:3030::6815:5ab9 answers · 443	yes
Mail servers (MX) have IPv6 None of the mail servers has an AAAA record. mx1.mail.ovh.net ✗mx3.mail.ovh.net ✗mx2.mail.ovh.net ✗	no
Nameservers have IPv6 2 of 2 nameservers checked have an AAAA record, so IPv6-only resolvers can look the domain up. javier.ns.cloudflare.com ✓nelly.ns.cloudflare.com ✓	yes

HTTPS over IPv6 · not part of the grade yet
Loads over IPv6 with a valid certificate after 1 redirect: HTTP 200.

https://growthlook.app/ via 2606:4700:3031::ac43:cbd3 → 302https://growthlook.app/login via 2606:4700:3031::ac43:cbd3 → 200

works

What's keeping growthlook.app from an A

Mail servers without IPv6
mx1.mail.ovh.net, mx3.mail.ovh.net, mx2.mail.ovh.net have no AAAA record, so mail from IPv6-only servers can't reach them directly. If a provider runs your mail, that's their setting; if you run it, add AAAA records for these hosts.

Check again

growthlook.app Has IPv6

A (IPv4)	172.67.203.211 104.21.90.185
AAAA (IPv6)	2606:4700:3031::ac43:cbd3 2606:4700:3030::6815:5ab9

www.growthlook.app Has IPv6

A (IPv4)	104.21.90.185 172.67.203.211
AAAA (IPv6)	2606:4700:3031::ac43:cbd3 2606:4700:3030::6815:5ab9

Browsers on dual-stack networks will usually pick IPv6 here (the "Happy Eyeballs" algorithm races both and prefers v6).

Copy the evidence — a citation-ready record of this measurement

IPv6 measurement: growthlook.app
Measured 2026-11-11 08:39:21 UTC by aaaa.bot (one server on Fly.io, region iad)

A (IPv4):    172.67.203.211, 104.21.90.185
AAAA (IPv6): 2606:4700:3031::ac43:cbd3, 2606:4700:3030::6815:5ab9
www AAAA:    2606:4700:3031::ac43:cbd3, 2606:4700:3030::6815:5ab9

Readiness grade B: Works over IPv6, with one gap: its mail servers lack IPv6.
- Website over IPv6: growthlook.app has 2 IPv6 addresses and answers on every one we tested.
    2606:4700:3031::ac43:cbd3: answers (TCP 443)
    2606:4700:3030::6815:5ab9: answers (TCP 443)
- www over IPv6: www.growthlook.app has 2 IPv6 addresses and answers on every one we tested.
    2606:4700:3031::ac43:cbd3: answers (TCP 443)
    2606:4700:3030::6815:5ab9: answers (TCP 443)
- Mail servers (MX) have IPv6: None of the mail servers has an AAAA record.
- Nameservers have IPv6: 2 of 2 nameservers checked have an AAAA record, so IPv6-only resolvers can look the domain up.

Reachability = a TCP connection opened on port 443 (or 80).

HTTPS over IPv6 (not graded): Loads over IPv6 with a valid certificate after 1 redirect: HTTP 200.
    https://growthlook.app/ via 2606:4700:3031::ac43:cbd3 -> HTTP 302, certificate: valid
    https://growthlook.app/login via 2606:4700:3031::ac43:cbd3 -> HTTP 200, certificate: valid
DNS answers via DNS-over-HTTPS (Cloudflare). Method: https://aaaa.bot/method
Permanent link: https://aaaa.bot/r/rjJSHItSLi

Permanent link: aaaa.bot/r/rjJSHItSLi · How we measure

Checked 2026-11-11 08:39:21 UTC. Full DNS report: dns.pizza/domain/growthlook.app · Age, certificate and blocklists: how.is/growthlook.app · JSON: /api/v1/growthlook.app