Yes — semantic.inc has IPv6.

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

IPv6 readiness

Website, mail and DNS all work over IPv6.

Website over IPv6 semantic.inc has 4 IPv6 addresses and answers on every one we tested. ✓ 2606:50c0:8003::153 answers · 443✓ 2606:50c0:8001::153 answers · 443✓ 2606:50c0:8000::153 answers · 443✓ 2606:50c0:8002::153 answers · 443	yes
www over IPv6 www.semantic.inc has 4 IPv6 addresses and answers on every one we tested. ✓ 2606:50c0:8003::153 answers · 443✓ 2606:50c0:8001::153 answers · 443✓ 2606:50c0:8000::153 answers · 443✓ 2606:50c0:8002::153 answers · 443	yes
Mail servers (MX) have IPv6 Every mail server has an AAAA record. aspmx.l.google.com ✓alt1.aspmx.l.google.com ✓alt2.aspmx.l.google.com ✓alt3.aspmx.l.google.com ✓alt4.aspmx.l.google.com ✓	yes
Nameservers have IPv6 2 of 2 nameservers checked have an AAAA record, so IPv6-only resolvers can look the domain up. ns65.domaincontrol.com ✓ns66.domaincontrol.com ✓	yes

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

https://semantic.inc/ via 2606:50c0:8003::153 → 200

works

Nothing keeping you from an A

Nothing to fix
Show it off: add the badge to your README.
[![IPv6](https://aaaa.bot/badge/semantic.inc.svg)](https://aaaa.bot/semantic.inc)

Check again

semantic.inc Has IPv6

A (IPv4)	185.199.111.153 185.199.109.153 185.199.110.153 185.199.108.153
AAAA (IPv6)	2606:50c0:8003::153 2606:50c0:8001::153 2606:50c0:8000::153 2606:50c0:8002::153

www.semantic.inc Has IPv6

Alias of	semantic.inc
A (IPv4)	185.199.111.153 185.199.109.153 185.199.110.153 185.199.108.153
AAAA (IPv6)	2606:50c0:8003::153 2606:50c0:8001::153 2606:50c0:8000::153 2606:50c0:8002::153

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: semantic.inc
Measured 2026-11-01 20:28:40 UTC by aaaa.bot (one server on Fly.io, region iad)

A (IPv4):    185.199.111.153, 185.199.109.153, 185.199.110.153, 185.199.108.153
AAAA (IPv6): 2606:50c0:8003::153, 2606:50c0:8001::153, 2606:50c0:8000::153, 2606:50c0:8002::153
www AAAA:    2606:50c0:8003::153, 2606:50c0:8001::153, 2606:50c0:8000::153, 2606:50c0:8002::153

Readiness grade A: Website, mail and DNS all work over IPv6.
- Website over IPv6: semantic.inc has 4 IPv6 addresses and answers on every one we tested.
    2606:50c0:8003::153: answers (TCP 443)
    2606:50c0:8001::153: answers (TCP 443)
    2606:50c0:8000::153: answers (TCP 443)
    2606:50c0:8002::153: answers (TCP 443)
- www over IPv6: www.semantic.inc has 4 IPv6 addresses and answers on every one we tested.
    2606:50c0:8003::153: answers (TCP 443)
    2606:50c0:8001::153: answers (TCP 443)
    2606:50c0:8000::153: answers (TCP 443)
    2606:50c0:8002::153: answers (TCP 443)
- Mail servers (MX) have IPv6: Every mail server 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: HTTP 200.
    https://semantic.inc/ via 2606:50c0:8003::153 -> HTTP 200, certificate: valid
DNS answers via DNS-over-HTTPS (Cloudflare). Method: https://aaaa.bot/method
Permanent link: https://aaaa.bot/r/kDSrevu6mX

Permanent link: aaaa.bot/r/kDSrevu6mX · How we measure

Checked 2026-11-01 20:28:40 UTC. Full DNS report: dns.pizza/domain/semantic.inc · JSON: /api/v1/semantic.inc