diff --git a/importarr/main.py b/importarr/main.py
index 66c7c75..3124ae2 100644
--- a/importarr/main.py
+++ b/importarr/main.py
@@ -4,6 +4,7 @@ from pathlib import Path
 from typing import Annotated
 
 import uvicorn
+import httpx
 from fastapi import Depends, FastAPI, Header, HTTPException, Request
 from fastapi.responses import HTMLResponse
 from fastapi.staticfiles import StaticFiles
@@ -50,6 +51,12 @@ class AppSettingsUpdate(BaseModel):
     sonarr_api_key: str | None = None
 
 
+class ConnectionTestRequest(BaseModel):
+    service: str
+    url: str
+    api_key: str | None = None
+
+
 def load_ui_settings() -> None:
     for key in ("sab_url", "sab_api_key", "radarr_url", "radarr_api_key", "sonarr_url", "sonarr_api_key"):
         stored = state.get_app_state(key)
@@ -136,6 +143,33 @@ def update_ui_settings(payload: AppSettingsUpdate, _: None = Depends(require_wri
     return get_ui_settings()
 
 
+@app.post("/api/settings/test-connection")
+async def test_connection(payload: ConnectionTestRequest, _: None = Depends(require_write_auth)) -> dict[str, object]:
+    service = payload.service.strip().lower()
+    url = payload.url.strip().rstrip("/")
+    api_key = (payload.api_key or "").strip() or None
+    if service not in {"sabnzbd", "radarr", "sonarr"}:
+        raise HTTPException(status_code=400, detail="service must be sabnzbd, radarr, or sonarr")
+    if not url:
+        raise HTTPException(status_code=400, detail="URL is required")
+    if api_key is None:
+        api_key = getattr(settings, f"{service if service != 'sabnzbd' else 'sab'}_api_key")
+    try:
+        if service == "sabnzbd":
+            data = await SabnzbdClient(url, api_key).queue()
+            return {"ok": True, "service": service, "message": f"Connected to SABnzbd; {len(data.get('queue', {}).get('slots', []))} queued jobs visible."}
+        headers = {"X-Api-Key": api_key} if api_key else {}
+        async with httpx.AsyncClient(timeout=15) as client:
+            response = await client.get(f"{url}/api/v3/system/status", headers=headers)
+            response.raise_for_status()
+            data = response.json()
+        name = str(data.get("appName") or service.title())
+        version = str(data.get("version") or "unknown version")
+        return {"ok": True, "service": service, "message": f"Connected to {name} {version}."}
+    except Exception as exc:
+        return {"ok": False, "service": service, "message": f"Connection failed: {exc.__class__.__name__}"}
+
+
 def control_status() -> dict[str, object]:
     mode = state.get_app_state("queue_mode", "running") or "running"
     current = state.get_app_state("current_job")
diff --git a/importarr/static/importarr.css b/importarr/static/importarr.css
index 04fc320..9d6daaf 100644
--- a/importarr/static/importarr.css
+++ b/importarr/static/importarr.css
@@ -1 +1 @@
-body{font-family:system-ui,sans-serif;margin:0;background:#111827;color:#e5e7eb}header,main{max-width:1100px;margin:auto;padding:1rem}.topbar{display:flex;justify-content:space-between;gap:1rem;align-items:center;background:#0f172a}.build{text-align:right}.build strong{font-size:1.2rem}.cards{display:grid;grid-template-columns:repeat(auto-fit,minmax(12rem,1fr));gap:1rem}.cards article,.panel{background:#1f2937;border-radius:.75rem;padding:1rem;margin-top:1rem}strong{display:block;font-size:2rem}span,small,dd{color:#9ca3af}table{width:100%;border-collapse:collapse;background:#1f2937;margin-top:1rem}th,td{padding:.6rem;border-bottom:1px solid #374151;text-align:left;vertical-align:top}input,button{padding:.6rem;border-radius:.4rem;border:1px solid #374151}button{background:#38bdf8;color:#082f49;font-weight:700;cursor:pointer}.danger{background:#f87171;color:#450a0a}.warn{background:#fbbf24;color:#451a03}.controls,.row-actions{display:flex;gap:.5rem;flex-wrap:wrap}.inline-form{display:flex;gap:.5rem;flex-wrap:wrap}.inline-form input[name=path]{min-width:min(100%,28rem);flex:1}.info{display:grid;grid-template-columns:10rem 1fr;gap:.4rem 1rem}.info dt{font-weight:700}.info dd{margin:0;overflow-wrap:anywhere}.state{background:#0f172a;border:1px solid #374151;border-radius:999px;padding:.15rem .5rem;display:inline-block}.section-title{display:flex;align-items:center;justify-content:space-between;gap:1rem}.job-group{margin-top:1.25rem}.job-group h3{display:flex;gap:.5rem;align-items:center}.job-group h3 span{font-size:.9rem;border:1px solid #374151;border-radius:999px;padding:.1rem .45rem}.file-name{font-size:1rem}.row-actions button{padding:.35rem .5rem}td small{display:block;overflow-wrap:anywhere}dialog{background:#1f2937;color:#e5e7eb;border:1px solid #374151;border-radius:.75rem;max-width:min(42rem,90vw)}dialog::backdrop{background:#0009}fieldset{border:1px solid #374151;border-radius:.5rem;margin:1rem 0;padding:1rem}label{display:grid;gap:.35rem;margin:.75rem 0}.hint{color:#9ca3af}
+body{font-family:system-ui,sans-serif;margin:0;background:#111827;color:#e5e7eb}header,main{max-width:1100px;margin:auto;padding:1rem}.topbar{display:flex;justify-content:space-between;gap:1rem;align-items:center;background:#0f172a}.build{text-align:right}.build strong{font-size:1.2rem}.cards{display:grid;grid-template-columns:repeat(auto-fit,minmax(12rem,1fr));gap:1rem}.cards article,.panel{background:#1f2937;border-radius:.75rem;padding:1rem;margin-top:1rem}strong{display:block;font-size:2rem}span,small,dd{color:#9ca3af}table{width:100%;border-collapse:collapse;background:#1f2937;margin-top:1rem}th,td{padding:.6rem;border-bottom:1px solid #374151;text-align:left;vertical-align:top}input,button{padding:.6rem;border-radius:.4rem;border:1px solid #374151}button{background:#38bdf8;color:#082f49;font-weight:700;cursor:pointer}.danger{background:#f87171;color:#450a0a}.warn{background:#fbbf24;color:#451a03}.controls,.row-actions{display:flex;gap:.5rem;flex-wrap:wrap}.inline-form{display:flex;gap:.5rem;flex-wrap:wrap}.inline-form input[name=path]{min-width:min(100%,28rem);flex:1}.info{display:grid;grid-template-columns:10rem 1fr;gap:.4rem 1rem}.info dt{font-weight:700}.info dd{margin:0;overflow-wrap:anywhere}.state{background:#0f172a;border:1px solid #374151;border-radius:999px;padding:.15rem .5rem;display:inline-block}.section-title{display:flex;align-items:center;justify-content:space-between;gap:1rem}.job-group{margin-top:1.25rem}.job-group h3{display:flex;gap:.5rem;align-items:center}.job-group h3 span{font-size:.9rem;border:1px solid #374151;border-radius:999px;padding:.1rem .45rem}.file-name{font-size:1rem}.row-actions button{padding:.35rem .5rem}td small{display:block;overflow-wrap:anywhere}dialog{background:#1f2937;color:#e5e7eb;border:1px solid #374151;border-radius:.75rem;max-width:min(42rem,90vw)}dialog::backdrop{background:#0009}fieldset{border:1px solid #374151;border-radius:.5rem;margin:1rem 0;padding:1rem}label{display:grid;gap:.35rem;margin:.75rem 0}.hint{color:#9ca3af}output{display:block;margin-top:.5rem;color:#9ca3af}.success{color:#86efac}.error{color:#fca5a5}
diff --git a/importarr/templates/index.html b/importarr/templates/index.html
index e9bebba..53c0f13 100644
--- a/importarr/templates/index.html
+++ b/importarr/templates/index.html
@@ -74,16 +74,19 @@
         <legend>SABnzbd</legend>
         <label>SAB URL <input name="sab_url" type="url" value="{{ status.sab_url }}" placeholder="http://sabnzbd:8080" required></label>
         <label>API token <input name="sab_api_key" type="password" placeholder="{% if status.sab_api_key_configured %}Configured; enter a new token to replace{% else %}SAB API token{% endif %}" autocomplete="off"></label>
+        <button type="button" data-test-connection="sabnzbd">Test SABnzbd connection</button><output id="sabnzbd-test-result"></output>
       </fieldset>
       <fieldset>
         <legend>Radarr</legend>
         <label>Radarr URL <input name="radarr_url" type="url" value="{{ status.radarr_url }}" placeholder="http://radarr:7878"></label>
         <label>API token <input name="radarr_api_key" type="password" placeholder="{% if status.radarr_api_key_configured %}Configured; enter a new token to replace{% else %}Radarr API token{% endif %}" autocomplete="off"></label>
+        <button type="button" data-test-connection="radarr">Test Radarr connection</button><output id="radarr-test-result"></output>
       </fieldset>
       <fieldset>
         <legend>Sonarr</legend>
         <label>Sonarr URL <input name="sonarr_url" type="url" value="{{ status.sonarr_url }}" placeholder="http://sonarr:8989"></label>
         <label>API token <input name="sonarr_api_key" type="password" placeholder="{% if status.sonarr_api_key_configured %}Configured; enter a new token to replace{% else %}Sonarr API token{% endif %}" autocomplete="off"></label>
+        <button type="button" data-test-connection="sonarr">Test Sonarr connection</button><output id="sonarr-test-result"></output>
       </fieldset>
       <p class="hint">Blank token fields clear the stored token. Environment values remain the startup defaults until saved here.</p>
       <button type="submit">Save settings</button>
@@ -103,6 +106,7 @@
   document.getElementById('open-settings').addEventListener('click',()=>document.getElementById('settings-dialog').showModal());
   document.getElementById('close-settings').addEventListener('click',()=>document.getElementById('settings-dialog').close());
   document.getElementById('settings-form').addEventListener('submit', async e=>{ e.preventDefault(); const body=Object.fromEntries(new FormData(e.target)); const response=await postJson('/api/settings',body); if(response.ok){ const data=await response.json(); document.getElementById('sab-token-status').textContent=data.sab_api_key_configured?'configured':'not configured'; ['sab_api_key','radarr_api_key','sonarr_api_key'].forEach(name=>e.target.elements[name].value=''); document.getElementById('settings-dialog').close(); } });
+  document.querySelectorAll('[data-test-connection]').forEach(button=>button.addEventListener('click', async()=>{ const form=document.getElementById('settings-form'); const service=button.dataset.testConnection; const prefix=service==='sabnzbd'?'sab':service; const output=document.getElementById(`${service}-test-result`); output.textContent='Testing…'; output.className=''; const response=await postJson('/api/settings/test-connection',{service,url:form.elements[`${prefix}_url`].value,api_key:form.elements[`${prefix}_api_key`].value}); if(response.ok){ const data=await response.json(); output.textContent=data.message; output.className=data.ok?'success':'error'; } }));
   document.getElementById('force-run').addEventListener('click', async()=>{ await postJson('/api/import/run-now',{force:true}); await refresh(); });
   refresh(); setInterval(refresh, 10000);
   </script>
diff --git a/tests/test_status.py b/tests/test_status.py
index 9fe6549..4254ec8 100644
--- a/tests/test_status.py
+++ b/tests/test_status.py
@@ -46,6 +46,9 @@ def test_index_renders_settings_dialog(tmp_path, monkeypatch):
     assert "SABnzbd" in response.text
     assert "Radarr" in response.text
     assert "Sonarr" in response.text
+    assert "Test SABnzbd connection" in response.text
+    assert "Test Radarr connection" in response.text
+    assert "Test Sonarr connection" in response.text
 
 
 def test_settings_endpoint_persists_arr_connection_values(tmp_path, monkeypatch):
@@ -77,3 +80,37 @@ def test_settings_endpoint_persists_arr_connection_values(tmp_path, monkeypatch)
     }
     assert main.settings.sab_api_key == "sab-secret"
     assert main.state.get_app_state("radarr_api_key") == "radarr-secret"
+
+
+def test_sab_connection_test_reports_success(tmp_path, monkeypatch):
+    monkeypatch.setenv("IMPORTARR_STATE_PATH", str(tmp_path / "state.db"))
+    import importarr.main as main
+
+    from fastapi.testclient import TestClient
+
+    async def fake_queue(self):
+        return {"queue": {"slots": [{"name": "one"}, {"name": "two"}]}}
+
+    monkeypatch.setattr(main.SabnzbdClient, "queue", fake_queue)
+
+    response = TestClient(main.app).post(
+        "/api/settings/test-connection",
+        json={"service": "sabnzbd", "url": "http://sab:8080", "api_key": "secret"},
+    )
+
+    assert response.status_code == 200
+    assert response.json() == {"ok": True, "service": "sabnzbd", "message": "Connected to SABnzbd; 2 queued jobs visible."}
+
+
+def test_connection_test_rejects_unknown_service(tmp_path, monkeypatch):
+    monkeypatch.setenv("IMPORTARR_STATE_PATH", str(tmp_path / "state.db"))
+    import importarr.main as main
+
+    from fastapi.testclient import TestClient
+
+    response = TestClient(main.app).post(
+        "/api/settings/test-connection",
+        json={"service": "lidarr", "url": "http://lidarr:8686"},
+    )
+
+    assert response.status_code == 400