diff --git a/Ideen.md b/Ideen.md
index 37f6fdf..3da3c3b 100644
--- a/Ideen.md
+++ b/Ideen.md
@@ -7,7 +7,6 @@
 
 - api/ui: Türchen mit Tag "0" einem zufälligen Tag zuweisen
 - api/?: Option "custom Zuordnung Buchstaben" (standard leer)
-- api: `config.solution` - whitespace="IGNORE"->"REMOVE" umbenennen, +Sonderzeichen
 - ui: `confirm` durch bulma Komponente(n) ersetzen
 
 # Erledigt
@@ -20,3 +19,4 @@
 - Nach einigen Sekunden: Meldung "Türchen anzeigen?"
 - `alert` durch bulma Komponente(n) ersetzen
 - api: admin Login case sensitivity (username "admin" == "AdMiN")
+- api: `config.solution` - whitespace="IGNORE"->"REMOVE" umbenennen, +Sonderzeichen
diff --git a/api/advent22_api/core/config.py b/api/advent22_api/core/config.py
index ebc1ac9..97b5461 100644
--- a/api/advent22_api/core/config.py
+++ b/api/advent22_api/core/config.py
@@ -29,7 +29,12 @@ class TransformedString(BaseModel):
         # whitespace entfernen
         REMOVE = "REMOVE"
 
-    # special chars
+    class __SpecialChars(str, Enum):
+        # unverändert
+        KEEP = "KEEP"
+
+        # Sonderzeichen entfernen
+        REMOVE = "REMOVE"
 
     class __Case(str, Enum):
         # unverändert
@@ -47,6 +52,7 @@ class TransformedString(BaseModel):
     value: str
 
     whitespace: __Whitespace = __Whitespace.REMOVE
+    special_chars: __SpecialChars = __SpecialChars.REMOVE
     case: __Case = __Case.UPPER
 
     @field_validator("whitespace", "case", mode="before")
@@ -67,6 +73,10 @@ class TransformedString(BaseModel):
         elif self.whitespace is TransformedString.__Whitespace.REMOVE:
             result = re.sub(string=result, pattern=r"\s+", repl="")
 
+        # Sonderzeichen verarbeiten
+        if self.special_chars is TransformedString.__SpecialChars.REMOVE:
+            result = re.sub(string=result, pattern=r"[^a-zA-Z0-9\s]+", repl="")
+
         # Groß-/Kleinschreibung verarbeiten
         if self.case is TransformedString.__Case.UPPER:
             result = result.upper()
diff --git a/api/advent22_api/routers/admin.py b/api/advent22_api/routers/admin.py
index e1b6496..45dc83a 100644
--- a/api/advent22_api/routers/admin.py
+++ b/api/advent22_api/routers/admin.py
@@ -31,6 +31,7 @@ class AdminConfigModel(BaseModel):
     class __Solution(BaseModel):
         value: str
         whitespace: str
+        special_chars: str
         case: str
         clean: str
 
@@ -81,6 +82,7 @@ async def get_config_model(
             "solution": {
                 "value": cfg.solution.value,
                 "whitespace": cfg.solution.whitespace,
+                "special_chars": cfg.solution.special_chars,
                 "case": cfg.solution.case,
                 "clean": cfg.solution.clean,
             },
diff --git a/ui/src/components/admin/ConfigView.vue b/ui/src/components/admin/ConfigView.vue
index 4acddb1..eb0e9e4 100644
--- a/ui/src/components/admin/ConfigView.vue
+++ b/ui/src/components/admin/ConfigView.vue
@@ -27,6 +27,12 @@
                   {{ admin_config_model.solution.whitespace }}
                 </span>
               </dd>
+              <dd>
+                Sonderzeichen:
+                <span class="is-uppercase is-family-monospace">
+                  {{ admin_config_model.solution.special_chars }}
+                </span>
+              </dd>
               <dd>
                 Buchstaben:
                 <span class="is-uppercase is-family-monospace">
@@ -184,6 +190,7 @@ export default class extends Vue {
     solution: {
       value: "ABCDEFGHIJKLMNOPQRSTUVWXYZ",
       whitespace: "KEEP",
+      special_chars: "KEEP",
       case: "KEEP",
       clean: "ABCDEFGHIJKLMNOPQRSTUVWXYZ",
     },
diff --git a/ui/src/lib/api.ts b/ui/src/lib/api.ts
index a67e080..f7a1874 100644
--- a/ui/src/lib/api.ts
+++ b/ui/src/lib/api.ts
@@ -2,6 +2,7 @@ export interface AdminConfigModel {
   solution: {
     value: string;
     whitespace: string;
+    special_chars: string;
     case: string;
     clean: string;
   };