Audit: slack.com

Audited on 3 Sep 2026

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76
overall score
On-page SEO
0
Crawlability
100
TLS & security
92
Network
83
Email
100
DNS
83

The site is up, but slow · responded in 99 ms

  • Reachable 1% of the last 24 hours
  • Outages cost you traffic and rankings while they last, and they rarely happen while you are watching.
Live status: Slack → Email me if it goes down →

On-page SEO

0/100
  • ? Page indexing The page was not fetched
  • ? On-page markup The page was not fetched

Crawlability

100/100
  • ✓ robots.txt present + valid Parsed cleanly · 3 sitemap(s) declared
  • ✓ Sitemap index reachable 13 child sitemap(s)

TLS & security

92/100
  • ✓ TLS handshake succeeds
  • ✓ Certificate not expiring soon 44 days left

Network

83/100
  • ✓ Hostname resolves to an A record 3.143.53.1
  • ! Server header does not leak version

Email

100/100
  • ✓ MX records valid + reachable
  • ✓ SPF record present v=spf1 include:_spf.qualtrics.com include:mail.zendesk.com include:_spfextra.slack.com -all
  • ✓ DMARC record present
  • ✓ DMARC policy enforced p=reject
  • ✓ DKIM key published selector=default

DNS

83/100
  • ✓ A records resolve
  • ✓ NS records present
  • ✓ MX records present
  • ✗ DNS resolvers agree on the same A record 60% of 12 resolvers agree
  • ✓ Domain registration not expiring soon 393 days left
  • ✓ Domain is established 33y 10m 11d (1992-10-21)

What changed

Nothing has changed on slack.com since we started watching it.

Certificates expire, DNS gets edited, a header goes missing in a deploy. Prove the domain is yours and we watch it on a schedule — free — and email you the moment something moves, so you hear it from us instead of from a customer.

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Subdomains discovered 🔒 Pro

1680 via Certificate Transparency · 500+ truncated

We found 1680 subdomains for slack.com via Certificate Transparency logs.

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Tech stack detected

2 technologies · Pro: track changes over time →

Signature-based identification from the public homepage. Pattern set is fixed; nothing is sent to third parties.

Analytics

  • Google Analytics

Server

  • Header value Apache

A certificate that expires on Tuesday should not wait until Friday. Prove a domain is yours and we check it free, once a week, emailing you anything that changed. Pro checks it once a day, looks at every host on the domain, and keeps 365 days of history — so you hear about a problem in hours rather than days.

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