diff --git a/app/src/pages/Welcome.tsx b/app/src/pages/Welcome.tsx
index 952b04dd6..cf192ca12 100644
--- a/app/src/pages/Welcome.tsx
+++ b/app/src/pages/Welcome.tsx
@@ -3,7 +3,7 @@ import { useState } from 'react';
 import OAuthProviderButton from '../components/oauth/OAuthProviderButton';
 import { oauthProviderConfigs } from '../components/oauth/providerConfigs';
 import RotatingTetrahedronCanvas from '../components/RotatingTetrahedronCanvas';
-import { clearCoreRpcUrlCache } from '../services/coreRpcClient';
+import { clearCoreRpcUrlCache, testCoreRpcConnection } from '../services/coreRpcClient';
 import { useDeepLinkAuthState } from '../store/deepLinkAuthState';
 import {
   clearStoredRpcUrl,
@@ -65,11 +65,7 @@ const Welcome = () => {
     setRpcUrlError(null);
 
     try {
-      const response = await fetch(normalized, {
-        method: 'POST',
-        headers: { 'Content-Type': 'application/json' },
-        body: JSON.stringify({ jsonrpc: '2.0', id: 1, method: 'openhuman.ping', params: {} }),
-      });
+      const response = await testCoreRpcConnection(normalized);
 
       if (response.ok || response.status === 405) {
         setSaveSuccess(true);
diff --git a/app/src/services/__tests__/coreRpcClient.test.ts b/app/src/services/__tests__/coreRpcClient.test.ts
index 776b19d0d..00347f9d3 100644
--- a/app/src/services/__tests__/coreRpcClient.test.ts
+++ b/app/src/services/__tests__/coreRpcClient.test.ts
@@ -421,4 +421,76 @@ describe('coreRpcClient', () => {
     expect(tokenCalls).toBe(1);
     expect(fetch).not.toHaveBeenCalled();
   });
+
+  describe('testCoreRpcConnection', () => {
+    test('POSTs an openhuman.ping JSON-RPC envelope to the supplied URL', async () => {
+      vi.resetModules();
+      vi.mocked(isTauri).mockReturnValue(false);
+      const { testCoreRpcConnection } = await import('../coreRpcClient');
+      const fetchMock = vi.mocked(fetch);
+      fetchMock.mockResolvedValueOnce({ ok: true, status: 200 } as Response);
+
+      await testCoreRpcConnection('http://example.test:7788/rpc');
+
+      expect(fetchMock).toHaveBeenCalledTimes(1);
+      const [url, init] = fetchMock.mock.calls[0];
+      expect(url).toBe('http://example.test:7788/rpc');
+      const requestInit = init as RequestInit;
+      expect(requestInit.method).toBe('POST');
+      expect(JSON.parse(requestInit.body as string)).toMatchObject({
+        jsonrpc: '2.0',
+        id: 1,
+        method: 'openhuman.ping',
+        params: {},
+      });
+    });
+
+    test('omits Authorization header when no bearer token is available (non-Tauri)', async () => {
+      vi.resetModules();
+      vi.mocked(isTauri).mockReturnValue(false);
+      const { testCoreRpcConnection } = await import('../coreRpcClient');
+      const fetchMock = vi.mocked(fetch);
+      fetchMock.mockResolvedValueOnce({ ok: true, status: 200 } as Response);
+
+      await testCoreRpcConnection('http://example.test:7788/rpc');
+
+      const requestInit = fetchMock.mock.calls[0][1] as RequestInit;
+      const headers = requestInit.headers as Record<string, string>;
+      expect(headers).toMatchObject({ 'Content-Type': 'application/json' });
+      expect(headers).not.toHaveProperty('Authorization');
+    });
+
+    test('attaches Authorization: Bearer when the Tauri bearer token resolves', async () => {
+      vi.resetModules();
+      vi.mocked(isTauri).mockReturnValue(true);
+      vi.mocked(invoke).mockImplementation(async (cmd: string) => {
+        if (cmd === 'core_rpc_token') return 'deadbeef';
+        throw new Error(`unexpected command: ${cmd}`);
+      });
+      const { testCoreRpcConnection } = await import('../coreRpcClient');
+      const fetchMock = vi.mocked(fetch);
+      fetchMock.mockResolvedValueOnce({ ok: true, status: 200 } as Response);
+
+      await testCoreRpcConnection('http://example.test:7788/rpc');
+
+      const requestInit = fetchMock.mock.calls[0][1] as RequestInit;
+      const headers = requestInit.headers as Record<string, string>;
+      expect(headers.Authorization).toBe('Bearer deadbeef');
+      expect(headers['Content-Type']).toBe('application/json');
+    });
+
+    test('returns the raw fetch Response so callers can inspect status/ok', async () => {
+      vi.resetModules();
+      vi.mocked(isTauri).mockReturnValue(false);
+      const { testCoreRpcConnection } = await import('../coreRpcClient');
+      const fetchMock = vi.mocked(fetch);
+      const probe = { ok: false, status: 405, statusText: 'Method Not Allowed' } as Response;
+      fetchMock.mockResolvedValueOnce(probe);
+
+      const response = await testCoreRpcConnection('http://example.test:7788/rpc');
+
+      expect(response).toBe(probe);
+      expect(response.status).toBe(405);
+    });
+  });
 });
diff --git a/app/src/services/coreRpcClient.ts b/app/src/services/coreRpcClient.ts
index aa05f36dc..70773f743 100644
--- a/app/src/services/coreRpcClient.ts
+++ b/app/src/services/coreRpcClient.ts
@@ -167,6 +167,30 @@ async function getCoreRpcToken(): Promise<string | null> {
   return resolvingCoreRpcToken;
 }
 
+/**
+ * Probe an arbitrary core RPC URL with `openhuman.ping`. Used by the
+ * Welcome page's "Test Connection" affordance to validate a user-entered
+ * RPC URL without going through the cached `getCoreRpcUrl` resolution.
+ *
+ * Encapsulates the bearer-token + JSON-RPC envelope assembly that would
+ * otherwise sit in the calling component, keeping all RPC client behavior
+ * inside the service per the project guideline ("Keep Tauri IPC and RPC
+ * client calls localized to services … do not scatter `invoke()` or
+ * direct RPC calls throughout components").
+ */
+export async function testCoreRpcConnection(url: string): Promise<Response> {
+  const token = await getCoreRpcToken();
+  const headers: Record<string, string> = { 'Content-Type': 'application/json' };
+  if (token) {
+    headers.Authorization = `Bearer ${token}`;
+  }
+  return fetch(url, {
+    method: 'POST',
+    headers,
+    body: JSON.stringify({ jsonrpc: '2.0', id: 1, method: 'openhuman.ping', params: {} }),
+  });
+}
+
 export async function getCoreHttpBaseUrl(): Promise<string> {
   const rpcUrl = await getCoreRpcUrl();
   const url = new URL(rpcUrl);