diff --git a/src/keyserver_bot/hooks.py b/src/keyserver_bot/hooks.py
index 93f2ed0..4af5974 100644
--- a/src/keyserver_bot/hooks.py
+++ b/src/keyserver_bot/hooks.py
@@ -1,4 +1,6 @@
 #!/usr/bin/env python3
+import re
+
 from deltachat_rpc_client import events, run_bot_cli, EventType, Message
 
 from keyserver_bot.wkd import request_from_wkd
@@ -7,20 +9,22 @@ from keyserver_bot.vcard import construct_vcard, save_vcard
 
 hooks = events.HookCollection()
 
-
-@hooks.on(events.RawEvent)
-def log_event(event):
-    print(event)
-    if event.kind == EventType.MSG_DELIVERED or event.kind == EventType.MSG_FAILED:
-        msg = Message(event.account, event.msg_id).get_snapshot()
-        delete_data(msg)
+HELP_MSG = "If you send me an email address, "\
+           "I will fetch it's public PGP key "\
+           "(from WKD and keys.openpgp.org) "\
+           "and send you a contact you can encrypt to."
 
 
 @hooks.on(events.NewMessage)
-def echo(event):
+def command(event):
     snapshot = event.message_snapshot
+
     email = snapshot.text
-    # TODO: validate email RFC
+    regex = r'^[a-zA-Z0-9_.+-]+@[a-zA-Z0-9-]+\.[a-zA-Z0-9-.]+$'
+    if not re.match(regex, email):
+        snapshot.chat.send_text(HELP_MSG)
+        return
+
     public_key = request_key_by_email(email)
     if not public_key:
         snapshot.chat.send_text("Sorry, I could not find a key for this user.")
@@ -32,13 +36,6 @@ def echo(event):
     snapshot.chat.send_file(vcard_path)
 
 
-def delete_data(msg):
-    contacts = msg.chat.get_contacts()
-    msg.chat.delete()
-    for member in contacts:
-        member.delete()
-
-
 def request_key_by_email(email) -> str:
     domain = email.split("@")[1]
     public_key = request_from_wkd(email, domain)
@@ -49,6 +46,21 @@ def request_key_by_email(email) -> str:
     return public_key
 
 
+@hooks.on(events.RawEvent)
+def cleanup(event):
+    print(event)
+    if event.kind == EventType.MSG_DELIVERED or event.kind == EventType.MSG_FAILED:
+        msg = Message(event.account, event.msg_id).get_snapshot()
+        delete_data(msg)
+
+
+def delete_data(msg):
+    contacts = msg.chat.get_contacts()
+    msg.chat.delete()
+    for member in contacts:
+        member.delete()
+
+
 def main():
     # TODO: print invite link
     run_bot_cli(hooks)