SSL/TLS Certificate Lookup

Check a domain's SSL/TLS certificate — who issued it, when it expires, and whether the chain is trusted

SSL/TLS Certificate for slack-web-chat.com

Valid
Issued by (CA)
Let's Encrypt
Subject
slack-web-chat.com
Valid from
Jun 12, 2026
Valid until
Sep 10, 2026 (45 days remaining)
Public key
EC 384-bit
Serial
06DB4F177C824F03F421DED35B93B7FC0F75
SHA-256 fingerprint
35:1C:0E:40:89:F2:12:F1:68:24:91:AA:96:6F:43:2F:7F:F8:83:C6:A5:43:06:47:A1:D2:01:31:8A:A9:40:15
Chain
YE1 → Root YE → ISRG Root X2 → ISRG Root X1
Subject Alternative Names (3)
app.slack-web-chat.com, slack-web-chat.com, www.slack-web-chat.com

Certificate Authority Authorization (CAA)

No CAA policy is published for this domain — any certificate authority may issue for it.

This certificate has been served since Jul 21, 2026.

Never get surprised by slack-web-chat.com's certificate expiring

This is today's certificate. Turn on monitoring and we'll watch slack-web-chat.com continuously, notifying you the moment anything moves across all three signals:

Uptime

We visit the site from multiple regions worldwide and email you within minutes if it goes down, with a per-region breakdown so a real outage stands out from a regional blip.

DNS changes

We watch NS, MX, CAA, DNSSEC, CNAME and A/AAAA records, and identify the host, network, and ASN behind them, so a real migration or hijack stands out from routine noise.

TLS certificate

We warn you 30, 14, 7, and 1 days before it expires, and flag it if the issuing authority changes or the certificate is unexpectedly replaced.

Monitor this certificate free

Free for your first domain: uptime, DNS, and certificate together. No credit card.