diff --git a/frontend/src/components/views/WatchlistView.tsx b/frontend/src/components/views/WatchlistView.tsx
index ca987c2..ac1cb2c 100644
--- a/frontend/src/components/views/WatchlistView.tsx
+++ b/frontend/src/components/views/WatchlistView.tsx
@@ -1,10 +1,10 @@
 'use client';
 import { useState, useEffect, useCallback } from 'react';
 import { Eye, Plus, Trash2, Bell, Clock, RefreshCw, ChevronDown, ChevronUp, AlertTriangle, ArrowLeft, Pause, Play } from 'lucide-react';
-import { listWatchlists, createWatchlist, deleteWatchlist, setWatchlistPaused } from '@/lib/api';
 import { useTranslations } from '@/lib/i18n';
 import type { Watchlist, ScanType } from '@/lib/types';
 import { formatWatchlistChange } from '@/lib/watchlist-alert-utils';
+import { listWatchlists, createWatchlist, deleteWatchlist, setWatchlistPaused, testWebhook } from '@/lib/api';
 
 const SCAN_TYPES: (ScanType | 'auto')[] = ['auto', 'domain', 'ip', 'email', 'phone', 'username'];
 
@@ -32,6 +32,8 @@ export function WatchlistView({ onBack }: { onBack: () => void }) {
   const [scanType, setScanType] = useState<ScanType | 'auto'>('auto');
   const [interval, setIntervalHours] = useState(24);
   const [webhook, setWebhook] = useState('');
+  const [testingWebhook, setTestingWebhook] = useState(false);
+  const [webhookTestResult, setWebhookTestResult] = useState<{ ok: boolean; message: string } | null>(null);
 
   const load = useCallback(async () => {
     setLoading(true);
@@ -71,6 +73,20 @@ export function WatchlistView({ onBack }: { onBack: () => void }) {
     }
   };
 
+const handleTestWebhook = async () => {
+  if (!webhook.trim()) return;
+  setTestingWebhook(true);
+  setWebhookTestResult(null);
+  try {
+    await testWebhook(webhook.trim());
+    setWebhookTestResult({ ok: true, message: 'Test webhook delivered successfully.' });
+  } catch (e: unknown) {
+    setWebhookTestResult({ ok: false, message: e instanceof Error ? e.message : 'Test failed.' });
+  } finally {
+    setTestingWebhook(false);
+  }
+};
+
   const remove = async (id: string) => {
     try {
       await deleteWatchlist(id);
@@ -181,12 +197,27 @@ const exportAlertsCsv = (w: Watchlist) => {
           </div>
           <div className="sm:col-span-2">
             <label className="block text-[10px] uppercase tracking-wider text-text-3 mb-1">{t('watchlist.webhookUrl')}</label>
-            <input
-              value={webhook}
-              onChange={e => setWebhook(e.target.value)}
-              placeholder="https://hooks.slack.com/…"
-              className="w-full bg-surface-2 border border-border-1 rounded px-3 py-2 text-sm text-text-1 font-mono focus:outline-none focus:border-blue"
-            />
+            <div className="flex gap-2">
+              <input
+                value={webhook}
+                onChange={e => { setWebhook(e.target.value); setWebhookTestResult(null); }}
+                placeholder="https://hooks.slack.com/…"
+                className="flex-1 bg-surface-2 border border-border-1 rounded px-3 py-2 text-sm text-text-1 font-mono focus:outline-none focus:border-blue"
+              />
+              <button
+                type="button"
+                disabled={!webhook.trim() || testingWebhook}
+                onClick={handleTestWebhook}
+                className="px-3 py-2 text-xs rounded border border-border-1 bg-surface-2 text-text-2 hover:border-blue hover:text-blue disabled:opacity-40 whitespace-nowrap"
+              >
+                {testingWebhook ? 'Sending…' : 'Send test'}
+              </button>
+            </div>
+            {webhookTestResult && (
+              <p className={`text-xs mt-1 ${webhookTestResult.ok ? 'text-green' : 'text-red'}`}>
+                {webhookTestResult.message}
+              </p>
+            )}
           </div>
         </div>
         <button type="submit" disabled={creating || !target.trim()} className="btn-primary mt-3 disabled:opacity-50">
diff --git a/frontend/src/lib/api.ts b/frontend/src/lib/api.ts
index 077e10e..9c2140f 100644
--- a/frontend/src/lib/api.ts
+++ b/frontend/src/lib/api.ts
@@ -240,6 +240,10 @@ export function setWatchlistPaused(id: string, paused: boolean): Promise<Watchli
   return patch(`/api/watchlist/${id}`, { paused });
 }
 
+export function testWebhook(webhook_url: string): Promise<{ ok: boolean; url: string }> {
+  return post('/api/watchlist/test-webhook', { webhook_url });
+}
+
 export function getWatchlistAlerts(id: string): Promise<{ id: string; alerts: WatchlistAlert[] }> {
   return get(`/api/watchlist/${id}/alerts`);
 }
diff --git a/tests/test_webhook.py b/tests/test_webhook.py
index 1cc56f1..4acb1d1 100644
--- a/tests/test_webhook.py
+++ b/tests/test_webhook.py
@@ -67,3 +67,95 @@ def boom(*a, **kw):
         monkeypatch.setattr(app_mod._requests, "post", boom)
                         
         app_mod._send_webhook("https://hooks.example.com/prism", {"x": 1})
+
+
+class TestTestWebhookEndpoint:
+    """Tests for POST /api/watchlist/test-webhook"""
+
+    def _client(self, monkeypatch, fake_post=None):
+        from web import app as app_mod
+        from web import security
+        from fastapi.testclient import TestClient
+
+        monkeypatch.setattr(security, "_API_KEYS", ["test-key"])
+        monkeypatch.setattr("socket.gethostbyname", lambda h: "93.184.216.34")
+        monkeypatch.setattr(
+            app_mod._requests, "head",
+            lambda *a, **kw: (_ for _ in ()).throw(Exception("skip"))
+        )
+        if fake_post is not None:
+            monkeypatch.setattr(app_mod._requests, "post", fake_post)
+        return TestClient(app_mod.app, raise_server_exceptions=True)
+
+    def test_returns_ok_on_success(self, monkeypatch):
+        captured = {}
+
+        def fake_post(url, json=None, headers=None, timeout=None):
+            captured["url"] = url
+            captured["json"] = json
+
+        client = self._client(monkeypatch, fake_post)
+        resp = client.post(
+            "/api/watchlist/test-webhook",
+            json={"webhook_url": "https://hooks.example.com/prism"},
+            headers={"X-API-Key": "test-key"},
+        )
+        assert resp.status_code == 200
+        assert resp.json()["ok"] is True
+        assert captured["json"]["event"] == "watchlist_test"
+
+    def test_rejects_private_url(self, monkeypatch):
+        from web import app as app_mod
+        from web import security
+        from fastapi.testclient import TestClient
+
+        monkeypatch.setattr(security, "_API_KEYS", ["test-key"])
+        monkeypatch.setattr("socket.gethostbyname", lambda h: "10.0.0.1")
+        client = TestClient(app_mod.app, raise_server_exceptions=True)
+        resp = client.post(
+            "/api/watchlist/test-webhook",
+            json={"webhook_url": "http://internal.corp/hook"},
+            headers={"X-API-Key": "test-key"},
+        )
+        assert resp.status_code == 400
+        assert "error" in resp.json()
+
+    def test_rejects_invalid_scheme(self, monkeypatch):
+        client = self._client(monkeypatch)
+        resp = client.post(
+            "/api/watchlist/test-webhook",
+            json={"webhook_url": "ftp://example.com/hook"},
+            headers={"X-API-Key": "test-key"},
+        )
+        assert resp.status_code == 400
+
+    def test_requires_api_key(self, monkeypatch):
+        from web import app as app_mod
+        from web import security
+        from fastapi.testclient import TestClient
+
+        monkeypatch.setattr(security, "_API_KEYS", ["test-key"])
+        client = TestClient(app_mod.app, raise_server_exceptions=True)
+        resp = client.post(
+            "/api/watchlist/test-webhook",
+            json={"webhook_url": "https://hooks.example.com/prism"},
+        )
+        assert resp.status_code in (401, 403)
+
+    def test_payload_shape(self, monkeypatch):
+        captured = {}
+
+        def fake_post(url, json=None, headers=None, timeout=None):
+            captured["json"] = json
+
+        client = self._client(monkeypatch, fake_post)
+        client.post(
+            "/api/watchlist/test-webhook",
+            json={"webhook_url": "https://hooks.example.com/prism"},
+            headers={"X-API-Key": "test-key"},
+        )
+        payload = captured["json"]
+        assert payload["event"] == "watchlist_test"
+        assert "target" in payload
+        assert "added" in payload
+        assert "changes" in payload
\ No newline at end of file
diff --git a/web/app.py b/web/app.py
index 65b4028..2631be6 100644
--- a/web/app.py
+++ b/web/app.py
@@ -734,6 +734,31 @@ async def patch_watchlist_entry(request: Request, watch_id: str, req: WatchlistP
         return JSONResponse({"error": "Watchlist not found"}, status_code=404)
     return entry
 
+class TestWebhookRequest(BaseModel):
+    webhook_url: str
+
+@app.post("/api/watchlist/test-webhook", dependencies=[Depends(require_api_key)])
+@limiter.limit("10/minute")
+async def test_webhook(request: Request, req: TestWebhookRequest):
+    try:
+        url = _validate_webhook_url(req.webhook_url.strip())
+    except ValueError as e:
+        return JSONResponse({"error": str(e)}, status_code=400)
+    payload = {
+        "event": "watchlist_test",
+        "message": "This is a test webhook from Prism.",
+        "target": "example.com",
+        "scan_type": "domain",
+        "added": 1,
+        "removed": 0,
+        "changes": ["+test.example.com"],
+    }
+    try:
+        _send_webhook(url, payload)
+    except Exception as e:
+        return JSONResponse({"error": f"Webhook delivery failed: {e}"}, status_code=502)
+    return {"ok": True, "url": url}
+
 @app.post("/api/scan", dependencies=[Depends(require_api_key)])
 @limiter.limit("10/minute")
 async def start_scan(request: Request, req: ScanRequest):