Dev tools · alternatives · 2026

24 alternatives to Perimeter

Check your site's TLS, headers, DNS and accessibility

Below are 24 products that do a similar job, ranked by how close each is in meaning and then by launch-day votes.

1. 1
   SSLreminder▲78

   Keep the business running, get reminded to extend your SSL

   2021 · sslreminder.pro · its alternatives →

2. 2
   haveibeenexpired▲68

   No more expired SSL certificates

   2021 · haveibeenexpired.com · its alternatives →

3. 3
   Kit.domains▲198

   Hello Hacker News community, We are excited to announce the launch of KIT.DOMAINS, our new tool designed to simplify the management and monitoring of domains. KIT DOMAINS is a convenient and reliable solution for tracking the status of your domains and SSL certificates. With KIT DOMAINS, you will receive timely notifications about expirations and emerging issues, ensuring your sites remain operational and secure. Key features: - Expiration Tracking: Monitor the expiration dates of your domains to prevent accidental lapses. - SSL Certificate Monitoring: Keep your SSL certificates up-to-date…

   2024 · kit.domains · its alternatives →

4. 4
   Certificate Transparency Log Monitor▲53

   2016 · sslmate.com · its alternatives →

5. 5
   Monitorly▲76

   Get real-time alerts for your SSL expiry

   2022 · its alternatives →

6. 6
   Never have an SSL certificate expire again▲40

   Automated SSL certificate monitoring with expiration alerts, Certificate Transparency discovery, and Slack/Discord/Teams notifications. Prevent downtime with continuous monitoring.

   2022 · haveibeenexpired.com · its alternatives →

7. 7
   bypassed.me▲2

   📎169 free DNS, email, TLS diagnostics in one place + more!

   Jul 2026 · bypassed.me · its alternatives →

8. 8
   Free Certificate Monitoring via RSS▲120

   2024 · raphting.dev · its alternatives →

9. 9
   XSignal.io▲75

   Check your website with online vulnerability scanner

   2021 · its alternatives →

10. 10
    TLS cert expiration dashboard▲40

    A dashboard written in JavaScript & HTML to check the remaining time before a TLS certificate expires. - cmrunton/tls-dashboard

    2016 · github.com · its alternatives →

11. 11
    DMARC Checker▲70

    Verify your DMARC, DKIM, and SPF settings with our free checker. Prevent bad actors from impersonating your domain and improve email deliverability.

    2024 · dmarcchecker.app · its alternatives →

12. 12
    CertPost▲3

    SL monitoring that checks the certificate your server serves

    Aug 2026 · certpost.ai · its alternatives →

13. 13
    Certly▲7

    Know before your SSL, domain, or DNS breaks

    Jul 2026 · certly.dev · its alternatives →

14. 14
    SSL Remind▲63

    Never forget to renew your SSL certificates

    2020 · sslremind.com · its alternatives →

15. 15
    Osint tool that finds exposed files on domains▲58

    hey guys, wanted to show one of my side projects i just made public. the idea is basically another osint tool for pentesters and bug bounty hunters. it watches certificate transparency logs and checks newly-seen domains for exposed stuff like .env files, open .git dirs, config files, db dumps and so on, and puts whatever it finds into a searchable db. you just search a domain (or part of one) and see what's exposed. it's read-only and free. one thing i've been thinking about adding is a way to register for certain keywords and get notified when something new shows up for that search. would…

    Jul 2026 · search.cerast-intelligence.com · its alternatives →

16. 16
    SSL Monitoring Solution▲6

    Monitor SSL certs and avoid unexpected downtime

    2025 · its alternatives →

17. 17
    SiteLock▲3

    Free website security scanner that grades any site A to F

    May 2026 · its alternatives →

18. 18
    SSL Certificate Checker▲11

    Check SSL certificates across public endpoints

    Jul 2026 · apify.com · its alternatives →

19. 19
    IsItWorking.info▲7

    Monitor SSL Certificates. Be warned before they expire!

    2019 · isitworking.info · its alternatives →

20. 20
    OopsSSL▲2

    Web Security Scanning & Monitoring

    2025 · its alternatives →

21. 21
    CheckCyber▲4

    Scan any website for 24 security flaws in seconds

    Jul 2026 · checkcyber.fr · its alternatives →

22. 22
    SSL Checker▲4

    Check SSL certifications and monitor expiration dates.

    2018 · apps.apple.com · its alternatives →

23. 23
    CertFleet▲1

    SSL + uptime monitoring without the observability bill

    Aug 2026 · its alternatives →

24. 24
    Domain Scan Tools▲5

    Detect domain security issues before they hurt your business

    May 2026 · domainscan.tools · its alternatives →

Ranked by how close each launch is in meaning, then by votes. Prices were read from each product’s own site when checked and can change. Refine with your own description →