Monitor SSL certificates for multiple websites

To monitor ssl certificates multiple sites reliably, every brand hostname needs its own live TLS row—shared renewals do not excuse shared blind spots.

Agencies, holding companies, and platform teams evaluate monitoring when DNS sprawls across dozens of customer domains, regional TLDs, and legacy acquisitions. Procurement wants per-seat pricing; reality is per-hostname presentation risk.

The portfolio failure pattern is one nightly script against a CSV export. DNS changes hourly; the CSV is static. One missed CNAME strands a microsite on an expired default certificate while the row for the parent brand stays green.

You will define portfolio scope, prioritize hostnames, and choose tiers that scale checks without hiding limits in footnotes.

What you are actually buying

Multi-site monitoring is still live TLS at scale: each enrolled hostname receives scheduled handshakes, trust evaluation, and expiry extraction from what the public internet sees.

Portfolio grouping—tags, clients, or business units—turns hundreds of rows into queues operators can own. Without ownership metadata, alerts become noise.

Wildcard and SAN certificates mean one renewal event but many DNS names that must match the same serial on the wire. Wildcard vs SAN expiry monitoring explains why one cert object does not imply one probe.

Domain registration via RDAP layered across brands prevents renewal surprises when a regional TLD policy differs from .com.

Check interval and domain caps are the commercial levers. Free tiers prove handshake quality on a handful of names; paid tiers expand to twenty-five or one hundred hostnames with hourly polling.

Batch CSV workflows help discovery but not scheduling—compare check multiple domains SSL expiry CSV against continuous monitoring before you rely on exports alone. Certificate inventory and expiry dashboards describe how to visualize the resulting rows.

When you monitor ssl certificates multiple sites, prioritize enrollment order deliberately. Rank hostnames by revenue, authentication dependency, and SEO visibility before you fill a twenty-five-domain Starter plan with long-dead campaign subdomains. Acquired brands often ship with duplicate www and naked-apex patterns—both need rows even when marketing insists “they redirect.” Redirect listeners carry their own certificates; assuming the apex check covers www is how agencies discover client outages before the client does.

Agency contracts should state which hostnames sit inside the monitoring cap and which remain client-owned.external checks. That clarity prevents scope arguments when a regional microsite expires during a holiday sale and the SLA mentions “primary domain only.”

Evaluation checklist

Ten criteria for products that monitor ssl certificates multiple sites.

1. Per-hostname enrollment. No “unlimited subdomains” fine print that caps at ten probes.

2. Stated domain maximum per plan. 3, 25, and 100 style tiers set honest expectations for portfolios.

3. Hourly option for revenue sites. Daily may suffice for brochure brands; checkout domains need faster cadence.

4. Tagging or folders per client. Agencies must separate alert routing without separate accounts per customer.

5. Email alerts with deduplication. 30/14/7/1 thresholds once per cycle across the whole fleet.

6. Webhooks on team tiers. Slack and Discord carry multi-site incidents to the right channel.

7. Bulk onboarding. Paste lists or import CSV for initial enrollment after discovery.

8. Consistent external vantage. Probes must not run only inside one cloud account shared by half the portfolio.

9. Chain and SAN visibility per host. Trust failures on one subdomain should not be averaged away.

10. Instant ad-hoc check. /check validates a suspicious cell before opening client comms.

Discovery pass across a client list before you buy:

while read -r h; do
  [ -z "$h" ] && continue
  echo -n "$h "
  echo | openssl s_client -connect "${h}:443" -servername "${h}" 2>/dev/null \
    | openssl x509 -noout -enddate 2>/dev/null || echo "FAIL"
done < hostnames.txt

Use the output to prioritize paid slots, not as a substitute for scheduled monitoring.

After discovery, document expected serials per brand in a lightweight registry. When hourly monitoring fires on one client hostname while neighbors stay green, serial comparison tells you whether the incident is local misconfiguration or a shared CA expiry event. Multi-site operators who skip that discipline chase fourteen parallel renewals when one wildcard redeploy would have fixed half the fleet.

How ssldays fits

ssldays scales monitor ssl certificates multiple sites across plan tiers: Free for 3 domains (daily), Starter for 25 (hourly), Pro for 100 (hourly).

Each hostname gets live TLS checks with email alerts at 30, 14, 7, and 1 days. Slack and Discord webhooks accompany paid plans.

RDAP registration dates appear where registries publish them—useful when acquisitions bring unfamiliar TLD policies.

Start with critical hosts via /check; schedule the portfolio at /register. Upgrade when client count exceeds free limits or when hourly detection becomes non-negotiable for commerce properties.

Rolling upgrades from free to Starter often coincide with signing a multi-brand client—budget twenty-five slots for that client’s visible surface plus your own corporate properties, not for every historical subdomain still in DNS. Decommissioned hosts should leave the monitor list the same week CNAMEs disappear.

Common mistakes when choosing a monitor

Monitoring only client apex domains. www, shop, and api hostnames fail first; use your domain cap wisely.

One account shared without client tags. Cross-client alert noise erodes trust with every false positive.

Assuming wildcard purchase equals wildcard coverage. Deep subdomains and apex pairs still need explicit probes.

Staying on daily checks for entire portfolios. Mix critical hourly names on Starter while long-tail properties wait—not every vendor supports split intervals, so prioritize within tier limits.

Relying on annual manual audits. Certificates rotate quarterly; continuous monitoring beats yearly spreadsheets.

Ignoring registrar clocks on acquired brands. TLS may be fresh while transfer locks or expiry block the next validation.

Treating client staging URLs as out of scope. Demo environments on client-owned DNS still tarnish agency reputation when certificates expire mid-pitch.

Equal alert routing for commerce and brochure sites. Triage rules should page differently for checkout failures versus marketing blog warnings.

Next steps

Inventory public hostnames per brand, run spot checks at /check, and enroll the highest-risk set at /register. Map remaining names to an upgrade timeline as you approach domain caps. Pair the fleet view with certificate inventory and expiry dashboards practices so executives see one consolidated risk picture.

Schedule a monthly “hostname hygiene” pass: remove monitors for decommissioned brands, add monitors for launches shipped last sprint, and reconcile client contracts with enrolled rows. Portfolios rot quietly when acquisitions outpace DNS tickets—monitor ssl certificates multiple sites discipline is as much CRM hygiene as TLS engineering.