diff --git a/langs/en.json b/langs/en.json
index ff60ed212..842cb8ce5 100644
--- a/langs/en.json
+++ b/langs/en.json
@@ -847,6 +847,7 @@
         },
         "tooLong": "The text is too long, at most 255 characters are allowed. You have {count} characters now.",
         "url": {
+            "aggregator": "{host} is a third-party aggregator website. If possible, search the official website.",
             "description": "link to a website",
             "feedback": "This is not a valid web address"
         },
diff --git a/langs/nl.json b/langs/nl.json
index e7656fec0..322381062 100644
--- a/langs/nl.json
+++ b/langs/nl.json
@@ -703,6 +703,7 @@
         },
         "tooLong": "Deze tekst is te lang. De tekst heeft {count} lettertekens, er mogen maximaal 255 letters zijn",
         "url": {
+            "aggregator": "{host} is een aggregator-website. Gebruik de officiele website indien mogelijk.",
             "description": "een link naar een webpagina",
             "feedback": "Dit is geen geldige link"
         },
diff --git a/src/UI/InputElement/ValidatedInput.svelte b/src/UI/InputElement/ValidatedInput.svelte
index a13c355d3..30d023f6e 100644
--- a/src/UI/InputElement/ValidatedInput.svelte
+++ b/src/UI/InputElement/ValidatedInput.svelte
@@ -85,13 +85,12 @@
       feedback?.setData(undefined)
       return
     }
+    feedback?.setData(validator?.getFeedback(v, getCountry))
     if (!validator?.isValid(v, getCountry)) {
-      feedback?.setData(validator?.getFeedback(v, getCountry))
       value.setData(undefined)
       return
     }
 
-    feedback?.setData(undefined)
     if (selectedUnit.data) {
       value.setData(unit.toOsm(v, selectedUnit.data))
     } else {
diff --git a/src/UI/InputElement/Validators/UrlValidator.ts b/src/UI/InputElement/Validators/UrlValidator.ts
index c504a07ca..b4c671c97 100644
--- a/src/UI/InputElement/Validators/UrlValidator.ts
+++ b/src/UI/InputElement/Validators/UrlValidator.ts
@@ -1,16 +1,30 @@
 import { Validator } from "../Validator"
+import { Translation } from "../../i18n/Translation"
+import Translations from "../../i18n/Translations"
 
 export default class UrlValidator extends Validator {
     private readonly _forceHttps: boolean
+
+    private static readonly aggregatorWebsites = new Set<string>([
+        "booking.com",
+        "hotel-details-guide.com", "tripingguide.com",
+        "tripadvisor.com", "tripadvisor.co.uk", "tripadvisor.com.au",
+    ])
+
     constructor(name?: string, explanation?: string, forceHttps?: boolean) {
         super(
             name ?? "url",
             explanation ??
-                "The validatedTextField will format URLs to always be valid and have a https://-header (even though the 'https'-part will be hidden from the user. Furthermore, some tracking parameters will be removed",
-            "url"
+            "The validatedTextField will format URLs to always be valid and have a https://-header (even though the 'https'-part will be hidden from the user. Furthermore, some tracking parameters will be removed",
+            "url",
         )
         this._forceHttps = forceHttps ?? false
     }
+
+    /**
+     *
+     * new UrlValidator().reformat("https://example.com/page?fbclid=123456&utm_source=mastodon") // => "https://example.com/page"
+     */
     reformat(str: string): string {
         try {
             let url: URL
@@ -63,6 +77,33 @@ export default class UrlValidator extends Validator {
         }
     }
 
+    /**
+     *
+     * const v = new UrlValidator()
+     * v.getFeedback("example.").textFor("en") // => "This is not a valid web address"
+     * v.getFeedback("https://booking.com/some-hotel.html").textFor("en").indexOf("search the official website") > 0 // => true
+     *
+     */
+    getFeedback(s: string, getCountry?: () => string): Translation | undefined {
+        const upstream = super.getFeedback(s, getCountry)
+        if (upstream) {
+            return upstream
+        }
+        /*
+         Upstream calls 'isValid', which checks if it is an actual URL.
+         If we reach this point, we can safely assume 'new URL' will work
+        */
+        const url = new URL(s)
+        let host = url.host.toLowerCase()
+        if (host.startsWith("www.")) {
+            host = host.slice(4)
+        }
+        if (UrlValidator.aggregatorWebsites.has(host)) {
+            return Translations.t.validation.url.aggregator.Subs({ host })
+        }
+        return undefined
+    }
+
     isValid(str: string): boolean {
         try {
             if (