diff --git a/src/referrers.json b/src/referrers.json
index ae33f16..d314fad 100644
--- a/src/referrers.json
+++ b/src/referrers.json
@@ -80,6 +80,15 @@
       ],
       "category": "app"
     },
+    {
+      "name": "Castos Web Player",
+      "pattern": "^https://[a-z0-9]+\\.castos\\.com/(player|playlist-player)/",
+      "examples": [
+        "https://audience.castos.com/player/1641975",
+        "https://audience.castos.com/playlist-player/4310"
+      ],
+      "category": "host"
+    },
     {
       "name": "Castro",
       "pattern": "^https://castro\\.fm/",