diff --git a/langs/en.json b/langs/en.json
index e4e1cbda72..5d838da076 100644
--- a/langs/en.json
+++ b/langs/en.json
@@ -850,6 +850,9 @@
             "description": "a positive, whole number",
             "noZero": "Zero is not allowed"
         },
+        "regex": {
+            "description": "a regular expression"
+        },
         "slope": {
             "inputExplanation": "Place your phone on the ground with the top side of your phone pointing towards the top of the slope.",
             "inputIncorrect": "For correct measurements, make sure the arrow is within the green area."
diff --git a/src/Models/ThemeConfig/FilterConfig.ts b/src/Models/ThemeConfig/FilterConfig.ts
index 8e80b581ba..4dfddc64ba 100644
--- a/src/Models/ThemeConfig/FilterConfig.ts
+++ b/src/Models/ThemeConfig/FilterConfig.ts
@@ -60,7 +60,7 @@ export default class FilterConfig {
             }
 
             const fields: { name: string; type: ValidatorType }[] = (option.fields ?? []).map((f, i) => {
-                const type = <ValidatorType> f.type ?? "string"
+                const type = <ValidatorType> f.type ?? "regex"
                 if(Validators.availableTypes.indexOf(type) < 0){
                     throw `Invalid filter: type is not a valid validator. Did you mean one of ${Utils.sortedByLevenshteinDistance(type, <any>Validators.availableTypes, x => x).slice(0, 3)}`
                 }
diff --git a/src/UI/BigComponents/FilterviewWithFields.svelte b/src/UI/BigComponents/FilterviewWithFields.svelte
index 9d9a52e43c..5245c9c2f1 100644
--- a/src/UI/BigComponents/FilterviewWithFields.svelte
+++ b/src/UI/BigComponents/FilterviewWithFields.svelte
@@ -8,6 +8,8 @@
   import { Utils } from "../../Utils"
   import type { ValidatorType } from "../InputElement/Validators"
   import InputHelper from "../InputElement/InputHelper.svelte"
+  import { Translation } from "../i18n/Translation"
+  import Tr from "../Base/Tr.svelte"
 
   export let filteredLayer: FilteredLayer
   export let option: FilterConfigOption
@@ -36,7 +38,7 @@
     appliedFilter?.setData(FilteredLayer.fieldsToString(properties))
   }
 
-  let firstValue : UIEventSource<string>
+  let firstValue: UIEventSource<string>
   for (const field of option.fields) {
     // A bit of cheating: the 'parts' will have '}' suffixed for fields
     const src = new UIEventSource<string>(initialState[field.name] ?? "")
@@ -47,9 +49,10 @@
     onDestroy(
       src.stabilized(200).addCallback(() => {
         setFields()
-      }),
+      })
     )
   }
+  let feedback: UIEventSource<Translation> = new UIEventSource<Translation>(undefined)
 </script>
 
 <div class="low-interaction p-1 rounded-2xl px-3" class:interactive={$firstValue?.length > 0}>
@@ -58,11 +61,15 @@
       <!-- This is a field! -->
       <span class="mx-1">
         <InputHelper value={fieldValues[part["subs"]]} type={fieldTypes[part["subs"]]}>
-          <ValidatedInput slot="fallback" value={fieldValues[part["subs"]]} type={fieldTypes[part["subs"]]} />
+          <ValidatedInput slot="fallback" value={fieldValues[part["subs"]]} type={fieldTypes[part["subs"]]}
+                          {feedback} />
         </InputHelper>
       </span>
     {:else}
       {@html part["message"]}
     {/if}
   {/each}
+  {#if $feedback}
+    <Tr cls="alert" t={$feedback}/>
+  {/if}
 </div>
diff --git a/src/UI/InputElement/Validators.ts b/src/UI/InputElement/Validators.ts
index ec08969486..eb768f2b1d 100644
--- a/src/UI/InputElement/Validators.ts
+++ b/src/UI/InputElement/Validators.ts
@@ -15,9 +15,6 @@ import UrlValidator from "./Validators/UrlValidator"
 import PhoneValidator from "./Validators/PhoneValidator"
 import OpeningHoursValidator from "./Validators/OpeningHoursValidator"
 import ColorValidator from "./Validators/ColorValidator"
-import BaseUIElement from "../BaseUIElement"
-import Combine from "../Base/Combine"
-import Title from "../Base/Title"
 import SimpleTagValidator from "./Validators/SimpleTagValidator"
 import ImageUrlValidator from "./Validators/ImageUrlValidator"
 import TagKeyValidator from "./Validators/TagKeyValidator"
@@ -30,6 +27,7 @@ import SlopeValidator from "./Validators/SlopeValidator"
 import VeloparkValidator from "./Validators/VeloparkValidator"
 import NameSuggestionIndexValidator from "./Validators/NameSuggestionIndexValidator"
 import CurrencyValidator from "./Validators/CurrencyValidator"
+import RegexValidator from "./Validators/RegexValidator"
 
 export type ValidatorType = (typeof Validators.availableTypes)[number]
 
@@ -64,6 +62,7 @@ export default class Validators {
         "velopark",
         "nsi",
         "currency",
+        "regex"
     ] as const
 
     public static readonly AllValidators: ReadonlyArray<Validator> = [
@@ -95,6 +94,7 @@ export default class Validators {
         new VeloparkValidator(),
         new NameSuggestionIndexValidator(),
         new CurrencyValidator(),
+        new RegexValidator()
     ]
 
     private static _byType = Validators._byTypeConstructor()
diff --git a/src/UI/InputElement/Validators/RegexValidator.ts b/src/UI/InputElement/Validators/RegexValidator.ts
new file mode 100644
index 0000000000..9323db8fd9
--- /dev/null
+++ b/src/UI/InputElement/Validators/RegexValidator.ts
@@ -0,0 +1,22 @@
+import StringValidator from "./StringValidator"
+import { s } from "vitest/dist/env-afee91f0"
+import { Translation } from "../../i18n/Translation"
+import Translations from "../../i18n/Translations"
+
+export default class RegexValidator extends StringValidator{
+    constructor() {
+        super("regex", "Validates a regex")
+    }
+
+    getFeedback(s: string): Translation | undefined {
+        try{
+            new RegExp(s)
+        }catch (e) {
+            return Translations.T("Not a valid Regex: "+e)
+        }
+    }
+
+    isValid(s: string): boolean {
+        return this.getFeedback(s) === undefined
+    }
+}