diff --git a/check_morg_memberships.sh b/check_morg_memberships.sh
new file mode 100644
index 0000000..c18182b
--- /dev/null
+++ b/check_morg_memberships.sh
@@ -0,0 +1,64 @@
+#!/bin/sh
+# usage: define the variables below and add a cron job to run it every hour
+
+roomid=''
+mods_roomid=''  # for notifications
+bot_user_token='syt_...'
+morg_user_token='mct_...'
+user_ids_to_tag='["@user:domain.tld","@other_user.domain.tld"]'
+
+curl -s \
+  -X GET "https://xmr.mx/_matrix/client/r0/rooms/$roomid/members" \
+  -H "Authorization: Bearer $bot_user_token" \
+  > /tmp/members.xmrmx.json
+
+curl -s \
+  -X GET "https://matrix.org/_matrix/client/r0/rooms/$roomid/members" \
+  -H "Authorization: Bearer $morg_user_token" \
+  > /tmp/members.matrixorg.json
+
+jq '.chunk.[] | {membership: .content.membership, user_id: .state_key}' /tmp/members.matrixorg.json  \
+  | grep -A 1 'membership": "join' \
+  | grep user_id \
+  | perl -lpe 's/  "user_id": "([^"]+)"/$1/' \
+  | sort -u  > /tmp/members.matrixorg.csv
+
+jq '.chunk.[] | {membership: .content.membership, user_id: .state_key}' /tmp/members.xmrmx.json \
+  | grep -A 1 'membership": "join' \
+  | grep user_id \
+  | perl -lpe 's/  "user_id": "([^"]+)"/$1/' \
+  | sort -u > /tmp/members.xmrmx.csv
+
+diff /tmp/members.xmrmx.csv /tmp/members.matrixorg.csv | grep '@' > /tmp/discrepancies.txt
+is_positive=$?
+
+header="Membership discrepancies between xmr.mx and matrix.org detected:"
+body="$header\n$(cat /tmp/discrepancies.txt | sed 's/$/\\n/' | tr -d '\n')"
+formatted_body="<strong>$header</strong><pre>$(cat /tmp/discrepancies.txt | sed 's/$/\<br\>/' | tr -d '\n')</pre>"
+json_data=$(cat <<EOF
+  {
+    "msgtype": "m.text",
+    "format":"org.matrix.custom.html",
+    "body": "$body",
+    "formatted_body": "$formatted_body",
+    "m.mentions": {
+      "user_ids": $user_ids_to_tag
+    }
+  }
+EOF
+)
+
+if [ $is_positive -eq 0 ]; then
+  echo Discrepancies found.
+  txnId=$(date +%s%N | cut -b1-13)$(shuf -i 1000-9999 -n 1)
+  curl -s -X PUT \
+    "https://xmr.mx/_matrix/client/v3/rooms/$mods_roomid/send/m.room.message/m$txnId.00" \
+    -H "Authorization: Bearer $bot_user_token" \
+    -H "Content-Type: application/json" \
+    -d "$json_data" \
+    -o /dev/null \
+    -w "%{http_code}"
+  echo ""
+else
+  echo No discrepancies found.
+fi