Fastmail SSL certificate status

Valid — 83 days until expiry(fastmail.com)

This page shows the Fastmail SSL certificate as served by fastmail.com, read from a live TLS handshake by an independent CertPost probe and rechecked hourly: expiry, issuer, hostname coverage, the full chain, and the negotiated protocol.

Last checked 2026-09-20 07:46 UTC. CertPost is not affiliated with Fastmail.

Certificate details

Subject*.fastmail.com
IssuerYR2
Valid from2026-09-14
Expires2026-12-13
Days remaining83
Chain validyes
Hostname matchyes
Negotiated protocolTLSv1.3
TLS versions acceptedTLSv1.2, TLSv1.3

Hostnames this certificate covers

*.api.beta.fastmail.com, *.api.dogfood.fastmail.com, *.api.fastmail.com, *.api.qa.fastmail.com, *.beta.fastmail.com, *.caldav.fastmail.com, *.carddav.fastmail.com, *.dogfood.fastmail.com, *.fastmail.com, *.qa.fastmail.com, fastmail.com

Certificate chain as served

*.fastmail.comissued by YR2 · expires 2026-12-13
YR2issued by Root YR · expires 2028-09-02
Root YRissued by ISRG Root X1 · expires 2032-09-02
ISRG Root X1self-signed (root) · expires 2035-06-04

Common questions

Is the Fastmail SSL certificate expired?

At the last check, the certificate fastmail.com serves was within its validity period. It expires on 2026-12-13, 83 days from that check.

When does the Fastmail SSL certificate expire?

The certificate fastmail.com is currently serving expires on 2026-12-13 (83 days from the last check). Large services rotate certificates long before that date.

Who issued the Fastmail SSL certificate?

The certificate was issued by YR2.

How is this checked?

A CertPost probe opens a real TLS connection to fastmail.com on port 443 and reads the certificate the server presents, the same way a browser does. The result is cached and refreshed hourly.

Fastmail rotates certificates without downtime. Your own domains are the ones that expire quietly — watch 3 free, no card.

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