diff --git a/packages/web/src/hooks/useInstanceConnect.ts b/packages/web/src/hooks/useInstanceConnect.ts
new file mode 100644
index 00000000..419dfa94
--- /dev/null
+++ b/packages/web/src/hooks/useInstanceConnect.ts
@@ -0,0 +1,57 @@
+import { useState, useCallback } from 'react';
+import { useInstanceStore } from '../stores/instanceStore';
+import { DifferentPasswordError } from '../stores/instanceStore';
+
+/**
+ * Reusable hook for connecting to a federated instance.
+ * Handles both new connections (probeInstance → connectToRemote)
+ * and reconnections (reauthenticateInstance).
+ *
+ * All permanent state is delegated to instanceStore.
+ * This hook only holds ephemeral UI state.
+ */
+export function useInstanceConnect() {
+  const [isConnecting, setIsConnecting] = useState(false);
+  const [error, setError] = useState<string | null>(null);
+
+  const clearError = useCallback(() => setError(null), []);
+
+  const connect = useCallback(async (domain: string, password: string): Promise<'new' | 'reconnect'> => {
+    setIsConnecting(true);
+    setError(null);
+
+    try {
+      const store = useInstanceStore.getState();
+      // Determine if instance already exists in the store (disconnected/errored)
+      const existing = store.instances.find(i => {
+        try { return new URL(i.origin).host === domain; } catch { return false; }
+      });
+
+      if (existing) {
+        // Reconnect path: instance exists but is disconnected/errored
+        await store.reauthenticateInstance(existing.origin, password);
+        return 'reconnect';
+      } else {
+        // New connection path: probe → connect
+        const probeResult = await store.probeInstance(domain);
+        await store.connectToRemote(probeResult.origin, password);
+        return 'new';
+      }
+    } catch (err) {
+      let message: string;
+      if (err instanceof DifferentPasswordError) {
+        message = 'An account already exists on this instance with a different password. Enter the password for that account.';
+      } else if (err instanceof Error) {
+        message = err.message;
+      } else {
+        message = 'Connection failed';
+      }
+      setError(message);
+      throw err;
+    } finally {
+      setIsConnecting(false);
+    }
+  }, []);
+
+  return { connect, isConnecting, error, clearError };
+}