diff --git a/README.md b/README.md
index 5efdb0b..92c0f8b 100644
--- a/README.md
+++ b/README.md
@@ -361,6 +361,9 @@ executables.
   accounts.
 * [PhishStats](https://phishstats.info/) - Phishing Statistics with search for
   IP, domain and website title
+* [SecurityTrails](https://securitytrails.com/) - Historical and current WHOIS, 
+  historical and current DNS records, similar domains, certificate information
+  and other domain and IP related API and tools.
 * [SpamCop](https://www.spamcop.net/bl.shtml) - IP based spam block list.
 * [SpamHaus](https://www.spamhaus.org/lookup/) - Block list based on
   domains and IPs.