diff --git a/maigret/resources/data.json b/maigret/resources/data.json
index 141f875..903cdd6 100644
--- a/maigret/resources/data.json
+++ b/maigret/resources/data.json
@@ -20509,6 +20509,7 @@
             ],
             "checkType": "status_code",
             "alexaRank": 377057,
+            "regexCheck": "^[a-zA-Z0-9_]+$",
             "urlMain": "https://mastodon.cloud/",
             "url": "https://mastodon.cloud/@{username}",
             "usernameClaimed": "TheAdmin",
@@ -20517,7 +20518,7 @@
         "mastodon.social": {
             "checkType": "status_code",
             "alexaRank": 2073381,
-            "regexCheck": "^[^.]{1,}$",
+            "regexCheck": "^[a-zA-Z0-9_]+$",
             "urlMain": "https://chaos.social/",
             "url": "https://mastodon.social/@{username}",
             "usernameClaimed": "Gargron",
@@ -20532,6 +20533,7 @@
             ],
             "checkType": "status_code",
             "alexaRank": 1182037,
+            "regexCheck": "^[a-zA-Z0-9_]+$",
             "urlMain": "https://mastodon.xyz/",
             "url": "https://mastodon.technology/@{username}",
             "usernameClaimed": "ashfurrow",
@@ -20543,6 +20545,7 @@
             ],
             "checkType": "status_code",
             "alexaRank": 1182037,
+            "regexCheck": "^[a-zA-Z0-9_]+$",
             "urlMain": "https://mastodon.xyz/",
             "url": "https://mastodon.xyz/@{username}",
             "usernameClaimed": "TheKinrar",
@@ -29481,6 +29484,7 @@
                 "></label> <input name=",
                 "diaspora"
             ],
+            "regexCheck": "^[a-zA-Z0-9_]+$",
             "url": "https://fediverse.party/en/{username}",
             "urlMain": "https://fediverse.party",
             "usernameClaimed": "misskey",