Yes — shync.app has IPv6.

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

IPv6 readiness

Website, mail and DNS all work over IPv6.

Website over IPv6 shync.app has 2 IPv6 addresses and answers on every one we tested. ✓ 2606:4700:3035::6815:3981 answers · 443✓ 2606:4700:3033::ac43:a3e4 answers · 443	yes
Mail servers (MX) have IPv6 No MX records, so mail goes to the domain's own address (implicit MX). It has an AAAA record.	yes
Nameservers have IPv6 2 of 2 nameservers checked have an AAAA record, so IPv6-only resolvers can look the domain up. dolly.ns.cloudflare.com ✓viddy.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://shync.app/ via 2606:4700:3035::6815:3981 → 302https://throbbing-silence-b0bc.cloudflareaccess.com/cdn-cgi/access/login/shync.app?kid=e1d4c17bbd0149036e1305b99871cfcede0343657c8f68bed20c5eacb8a76aa1&meta=eyJ0eXAiOiJKV1QiLCJhbGciOiJSUzI1NiIsImtpZCI6IjY2ZDA2MDNjNGY3ODdlNDdlZTlkMWY1ZWRiZDMxYThkNmUyZDUzMjg4MmU0NzFjMmM2OGE3NTliMGQ4OTBlNGYifQ.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.f9XBpEdTPleTrI0LpypbhnrT18i4a1X7eKuYsBQ8kMfQgIYuAwtu76mrgapNmSpOijrKnR1h_UO-9zsR1E3TxRY7c45OxafgjJDAZ1SNzmN56chOch_Ghd1MUjHW32sNggwXYMdqAK-lF2eCO71J0kXDjMbdFv2IlJt8al7wiNc1DKGmevPTqAmZ2duCD84qrROR5yXAgmkFWJBxXJT18YmfwQnPTj-7PJBrrbcq1vNYSxeyo154cfeEy8cBrRSssZ6Ipdo3YMqj_Z_PWShpQlXbYOrM3oQE7HozQ1fW7KBSe9QUsUhokLp5egsJRmXIesscc6jwg1t-lSgSTeyU3w&redirect_url=%2F via 2606:4700:300a::6813:c21d → 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/shync.app.svg)](https://aaaa.bot/shync.app)

Check again

shync.app Has IPv6

A (IPv4)	172.67.163.228 104.21.57.129
AAAA (IPv6)	2606:4700:3035::6815:3981 2606:4700:3033::ac43:a3e4

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: shync.app
Measured 2026-11-07 18:56:11 UTC by aaaa.bot (one server on Fly.io, region iad)

A (IPv4):    172.67.163.228, 104.21.57.129
AAAA (IPv6): 2606:4700:3035::6815:3981, 2606:4700:3033::ac43:a3e4

Readiness grade A: Website, mail and DNS all work over IPv6.
- Website over IPv6: shync.app has 2 IPv6 addresses and answers on every one we tested.
    2606:4700:3035::6815:3981: answers (TCP 443)
    2606:4700:3033::ac43:a3e4: answers (TCP 443)
- Mail servers (MX) have IPv6: No MX records, so mail goes to the domain's own address (implicit MX). It 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://shync.app/ via 2606:4700:3035::6815:3981 -> HTTP 302, certificate: valid
    https://throbbing-silence-b0bc.cloudflareaccess.com/cdn-cgi/access/login/shync.app?kid=e1d4c17bbd0149036e1305b99871cfcede0343657c8f68bed20c5eacb8a76aa1&meta=eyJ0eXAiOiJKV1QiLCJhbGciOiJSUzI1NiIsImtpZCI6IjY2ZDA2MDNjNGY3ODdlNDdlZTlkMWY1ZWRiZDMxYThkNmUyZDUzMjg4MmU0NzFjMmM2OGE3NTliMGQ4OTBlNGYifQ.eyJ0eXBlIjoibWV0YSIsImF1ZCI6ImUxZDRjMTdiYmQwMTQ5MDM2ZTEzMDViOTk4NzFjZmNlZGUwMzQzNjU3YzhmNjhiZWQyMGM1ZWFjYjhhNzZhYTEiLCJob3N0bmFtZSI6InNoeW5jLmFwcCIsInJlZGlyZWN0X3VybCI6Ii8iLCJzZXJ2aWNlX3Rva2VuX3N0YXR1cyI6ZmFsc2UsImlzX3dhcnAiOmZhbHNlLCJpc19nYXRld2F5IjpmYWxzZSwiZXhwIjoxNzk0MDc4MDcxLCJuYmYiOjE3OTQwNzc3NzEsImlhdCI6MTc5NDA3Nzc3MSwiYXV0aF9zdGF0dXMiOiJOT05FIiwibXRsc19hdXRoIjp7ImNlcnRfaXNzdWVyX2RuIjoiIiwiY2VydF9zZXJpYWwiOiIiLCJjZXJ0X2lzc3Vlcl9za2kiOiIiLCJjZXJ0X3ByZXNlbnRlZCI6ZmFsc2UsImNvbW1vbl9uYW1lIjoiIiwiYXV0aF9zdGF0dXMiOiJOT05FIn0sInJlYWxfY291bnRyeSI6IlVTIiwiYXBwX3Nlc3Npb25faGFzaCI6Ijc1OTc3MDEwMzc1YzQ4NjBlMDFkMmMwOTMxMGU4MTU1MmIzYmU3NjJlZTZmOGMzNGNkYmM1YTA3NmVlY2JjYTMifQ.f9XBpEdTPleTrI0LpypbhnrT18i4a1X7eKuYsBQ8kMfQgIYuAwtu76mrgapNmSpOijrKnR1h_UO-9zsR1E3TxRY7c45OxafgjJDAZ1SNzmN56chOch_Ghd1MUjHW32sNggwXYMdqAK-lF2eCO71J0kXDjMbdFv2IlJt8al7wiNc1DKGmevPTqAmZ2duCD84qrROR5yXAgmkFWJBxXJT18YmfwQnPTj-7PJBrrbcq1vNYSxeyo154cfeEy8cBrRSssZ6Ipdo3YMqj_Z_PWShpQlXbYOrM3oQE7HozQ1fW7KBSe9QUsUhokLp5egsJRmXIesscc6jwg1t-lSgSTeyU3w&redirect_url=%2F via 2606:4700:300a::6813:c21d -> HTTP 200, certificate: valid
DNS answers via DNS-over-HTTPS (Cloudflare). Method: https://aaaa.bot/method
Permanent link: https://aaaa.bot/r/ryFYwHEuOg

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

Checked 2026-11-07 18:56:11 UTC. Full DNS report: dns.pizza/domain/shync.app · Age, certificate and blocklists: how.is/shync.app · JSON: /api/v1/shync.app