diff --git a/app/src/lib/nostr/signer.ts b/app/src/lib/nostr/signer.ts
new file mode 100644
index 0000000..de85753
--- /dev/null
+++ b/app/src/lib/nostr/signer.ts
@@ -0,0 +1,50 @@
+/**
+ * NIP-07-Wrapper für Browser-Extension-Signer (Alby, nos2x, Flamingo).
+ *
+ * `window.nostr` ist optional — wenn die Extension fehlt, liefern die Helper
+ * null zurück und der Aufrufer zeigt einen Hinweis an.
+ */
+
+declare global {
+	interface Window {
+		nostr?: {
+			getPublicKey(): Promise<string>;
+			signEvent(event: UnsignedEvent): Promise<SignedEvent>;
+		};
+	}
+}
+
+export interface UnsignedEvent {
+	kind: number;
+	tags: string[][];
+	content: string;
+	created_at: number;
+	pubkey: string;
+}
+
+export interface SignedEvent extends UnsignedEvent {
+	id: string;
+	sig: string;
+}
+
+export function hasNip07(): boolean {
+	return typeof window !== 'undefined' && !!window.nostr;
+}
+
+export async function getPublicKey(): Promise<string | null> {
+	if (!hasNip07()) return null;
+	try {
+		return await window.nostr!.getPublicKey();
+	} catch {
+		return null;
+	}
+}
+
+export async function signEvent(event: UnsignedEvent): Promise<SignedEvent | null> {
+	if (!hasNip07()) return null;
+	try {
+		return await window.nostr!.signEvent(event);
+	} catch {
+		return null;
+	}
+}