diff --git a/validate.py b/validate.py
index 26f931d..9461159 100644
--- a/validate.py
+++ b/validate.py
@@ -16,9 +16,17 @@ try:
 except ImportError:
     from yaml import Loader, Dumper
 
+ALLOWED_KEYS = ["name", "tags", "iban", "description"]
+TAGS_REGEXP = re.compile(r'[\w]+(?:,\s{0,1}[\w]+)*')
+
+def verbose_print(text, verbose):
+    if verbose:
+        print(text)
+
 
 @click.command(name="validate")
-def command():
+@click.option("--verbose", "-v", default=False, is_flag=True)
+def command(verbose):
     for profile in list_profiles():
         print(f"Checking {profile}:")
         db_path = build_database_filename(profile)
@@ -32,31 +40,52 @@ def command():
             if not data:
                 print(cf.green("  Ruleset is empty"))
             else:
+                errors = 0
                 for rule in data:
-                    # TODO: validate tag list
+                    # validate yaml keys:
+                    for key in rule.keys():
+                        if key not in ALLOWED_KEYS:
+                            verbose_print(cf.red(f"Rule uses the invalid key '{key}': {rule}"),verbose)
+                            errors+=1
+
+                    if not rule.get("tags"):
+                        verbose_print(cf.red(f"Rule has no tags: {rule}"),verbose)
+                        errors+=1
+
+                    if not TAGS_REGEXP.fullmatch(rule.get("tags")):
+                        verbose_print(cf.red(f"Rule has an invalid list of tags: {rule}"),verbose)
+                        errors+=1
+
 
                     # validate name regex
                     if rule.get("name"):
                         try:
                             re.compile(rule["name"])
                         except:
-                            print(cf.red(f"  Invalid name regex: '{rule.get('name')}'"))
+                            verbose_print(cf.red(f"  Invalid name regex: '{rule.get('name')}'"),verbose)
+                            errors+=1
 
                     # validate description regex
                     if rule.get("description"):
                         try:
                             re.compile(rule["description"])
                         except:
-                            print(cf.red(f"  Invalid description regex: '{rule.get('description')}'"))
+                            verbose_print(cf.red(f"  Invalid description regex: '{rule.get('description')}'"),verbose)
+                            errors+=1
 
                     # validate IBAN
                     if rule.get("iban"):
                         try:
                             IBAN(rule.get("iban"))
                         except:
-                            print(cf.red(f"  Invalid IBAN: '{rule.get('iban')}'"))
+                            verbose_print(cf.red(f"  Invalid IBAN: '{rule.get('iban')}'"), verbose)
+                            errors+=1
+
+                if errors == 0:
+                    print(cf.green(f"  All rules are valid"))
+                else:
+                    print(cf.red(f"  Found {errors} invalid rules"))
 
-                print(cf.green(f"  All rules are valid"))
         else:
             print(cf.red(f"  The rule file doesn't exists"))
             sys.exit(1)