diff --git a/app/api/listings/check-slug/route.ts b/app/api/listings/check-slug/route.ts
new file mode 100644
index 0000000..ee5e290
--- /dev/null
+++ b/app/api/listings/check-slug/route.ts
@@ -0,0 +1,18 @@
+import { NextResponse } from 'next/server';
+import { prisma } from '../../../../lib/prisma';
+
+export async function GET(req: Request) {
+  const url = new URL(req.url);
+  const slug = url.searchParams.get('slug')?.trim().toLowerCase();
+
+  if (!slug) {
+    return NextResponse.json({ error: 'Missing slug' }, { status: 400 });
+  }
+
+  const existing = await prisma.listingTranslation.findFirst({
+    where: { slug, listing: { removedAt: null } },
+    select: { id: true },
+  });
+
+  return NextResponse.json({ available: !existing });
+}
diff --git a/app/listings/new/page.tsx b/app/listings/new/page.tsx
index 1db8286..a6566fc 100644
--- a/app/listings/new/page.tsx
+++ b/app/listings/new/page.tsx
@@ -60,6 +60,7 @@ export default function NewListingPage() {
   const [isAuthed, setIsAuthed] = useState(false);
   const [aiResponse, setAiResponse] = useState('');
   const [copyStatus, setCopyStatus] = useState<'idle' | 'copied' | 'error'>('idle');
+  const [slugStatus, setSlugStatus] = useState<'idle' | 'checking' | 'available' | 'taken' | 'error'>('idle');
 
   useEffect(() => {
     setCurrentLocale(uiLocale as Locale);
@@ -214,6 +215,25 @@ export default function NewListingPage() {
     }));
   }
 
+  async function checkSlugAvailability() {
+    const value = slug.trim().toLowerCase();
+    if (!value) {
+      setSlugStatus('idle');
+      return;
+    }
+    setSlugStatus('checking');
+    try {
+      const res = await fetch(`/api/listings/check-slug?slug=${encodeURIComponent(value)}`, { cache: 'no-store' });
+      const data = await res.json();
+      if (!res.ok || typeof data.available !== 'boolean') {
+        throw new Error('bad response');
+      }
+      setSlugStatus(data.available ? 'available' : 'taken');
+    } catch (err) {
+      setSlugStatus('error');
+    }
+  }
+
   async function onSubmit(e: React.FormEvent) {
     e.preventDefault();
     setMessage(null);
@@ -325,8 +345,14 @@ export default function NewListingPage() {
       <form onSubmit={onSubmit} style={{ display: 'grid', gap: 10 }}>
         <label>
           {t('slugLabel')}
-          <input value={slug} onChange={(e) => setSlug(e.target.value)} required />
-          <div style={{ color: '#cbd5e1', fontSize: 12 }}>{t('slugHelp')}</div>
+          <input value={slug} onChange={(e) => setSlug(e.target.value)} onBlur={checkSlugAvailability} required />
+          <div style={{ display: 'flex', alignItems: 'center', gap: 8, marginTop: 4, flexWrap: 'wrap' }}>
+            <span style={{ color: '#cbd5e1', fontSize: 12 }}>{t('slugHelp')}</span>
+            {slugStatus === 'checking' ? <span style={{ color: '#cbd5e1', fontSize: 12 }}>{t('slugChecking')}</span> : null}
+            {slugStatus === 'available' ? <span style={{ color: '#34d399', fontSize: 12 }}>{t('slugAvailable')}</span> : null}
+            {slugStatus === 'taken' ? <span style={{ color: '#f87171', fontSize: 12 }}>{t('slugTaken')}</span> : null}
+            {slugStatus === 'error' ? <span style={{ color: '#facc15', fontSize: 12 }}>{t('slugCheckError')}</span> : null}
+          </div>
         </label>
         <div>
           <div style={{ display: 'flex', gap: 8, alignItems: 'center', flexWrap: 'wrap', marginBottom: 6 }}>
diff --git a/lib/i18n.ts b/lib/i18n.ts
index a531caf..9e4e3b7 100644
--- a/lib/i18n.ts
+++ b/lib/i18n.ts
@@ -155,6 +155,10 @@ const baseMessages = {
     loginToCreate: 'Please log in first to create a listing.',
     slugLabel: 'Slug',
     slugHelp: 'Unique link name, use lowercase letters and hyphens only (e.g. lake-cabin).',
+    slugChecking: 'Checking availability…',
+    slugAvailable: 'Slug is available',
+    slugTaken: 'Slug already in use',
+    slugCheckError: 'Could not check slug right now',
     localeInput: 'Locale',
     titleLabel: 'Title',
     descriptionLabel: 'Description',
@@ -420,6 +424,10 @@ const baseMessages = {
     loginToCreate: 'Kirjaudu ensin luodaksesi kohteen.',
     slugLabel: 'Osoitepolku',
     slugHelp: 'Yksilöllinen linkki, käytä pieniä kirjaimia ja väliviivoja (esim. saimaa-mokki).',
+    slugChecking: 'Tarkistetaan saatavuutta…',
+    slugAvailable: 'Slug on vapaa',
+    slugTaken: 'Slug on jo käytössä',
+    slugCheckError: 'Slugia ei voitu tarkistaa nyt',
     localeInput: 'Kieli',
     titleLabel: 'Otsikko',
     descriptionLabel: 'Kuvaus',
@@ -567,6 +575,10 @@ const svMessages: Record<keyof typeof baseMessages.en, string> = {
   aiApplySuccess: 'Översättningar uppdaterade från AI-svaret.',
   aiHelperNote: 'AI:n ska bara returnera JSON med samma nycklar.',
   translationMissing: 'Lägg till minst ett språk med titel och beskrivning.',
+  slugChecking: 'Kontrollerar tillgänglighet…',
+  slugAvailable: 'Sluggen är ledig',
+  slugTaken: 'Sluggen används redan',
+  slugCheckError: 'Kunde inte kontrollera sluggen nu',
 };
 
 export const messages = { ...baseMessages, sv: svMessages } as const;