Slack SSL certificate status

Valid — 73 days until expiry(slack.com)

This page shows the Slack SSL certificate as served by slack.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 2026-08-23 00:55 UTC. CertPost is not affiliated with Slack.

Certificate details

Subjectslack.com
IssuerYR1
Valid from2026-08-06
Expires2026-11-04
Days remaining73
Chain validyes
Hostname matchyes
Negotiated protocolTLSv1.3
TLS versions acceptedTLSv1.2, TLSv1.3

Hostnames this certificate covers

*.slack.com, slack.com

Certificate chain as served

slack.comissued by YR1 · expires 2026-11-04
YR1issued 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 Slack SSL certificate expired?

At the last check, the certificate slack.com serves was within its validity period. It expires on 2026-11-04, 73 days from that check.

When does the Slack SSL certificate expire?

The certificate slack.com is currently serving expires on 2026-11-04 (73 days from the last check). Large services rotate certificates long before that date.

Who issued the Slack SSL certificate?

The certificate was issued by YR1.

How is this checked?

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

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

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