Let's Encrypt
Free
Free TLS certificates from the nonprofit Internet Security Research Group.
Free checkers · Uptime and certificates
Free tier checked. Checked 14 Oct 2026.
Directory / Uptime and certificates
Category 10
Uptime and certificates
Uptime checks, TLS tests, and certificate expiry. Free certificates live in Free checkers.
Category top spot is open. If it sells, the paid listing will be labeled Sponsored and will sit above this list. It will not change the A–Z order. See the rate card.
OrionCmd
Made by usFreemiumUptime, certificates, and passive website checks, with one website free.
Uptime and certificates · Domain and DNS monitoring · Free checkers
Free tier checked. Checked 14 Oct 2026.
SSL Labs
FreeFree public test of a website's TLS configuration, run by Qualys.
Uptime and certificates · Free checkers
Free tier checked. Checked 14 Oct 2026.
UptimeRobot
FreemiumUptime monitoring with 50 monitors on the free plan.
Uptime and certificates · Free checkers
Free tier checked. Checked 14 Oct 2026.
URIports
PaidDMARC, DNS, and certificate monitoring with prices printed on the site.
DMARC, SPF, and DKIM · Domain and DNS monitoring · Uptime and certificates
Trial only. Checked 14 Oct 2026.