diff --git a/js/auth/signingAdapter.js b/js/auth/signingAdapter.js
new file mode 100644
index 00000000..cc854512
--- /dev/null
+++ b/js/auth/signingAdapter.js
@@ -0,0 +1,24 @@
+export function createNip07SigningAdapter({ extension } = {}) {
+  const resolvedExtension =
+    extension ||
+    (typeof window !== "undefined" && window?.nostr ? window.nostr : null);
+
+  const getPubkey = async () => {
+    if (!resolvedExtension) {
+      throw new Error("NIP-07 extension unavailable.");
+    }
+    return resolvedExtension.getPublicKey();
+  };
+
+  const signEvent = async (event) => {
+    if (!resolvedExtension) {
+      throw new Error("NIP-07 extension unavailable.");
+    }
+    return resolvedExtension.signEvent(event);
+  };
+
+  return {
+    getPubkey,
+    signEvent,
+  };
+}
diff --git a/tests/auth/signingAdapter.test.mjs b/tests/auth/signingAdapter.test.mjs
new file mode 100644
index 00000000..b946ae81
--- /dev/null
+++ b/tests/auth/signingAdapter.test.mjs
@@ -0,0 +1,91 @@
+import { test, describe, beforeEach, afterEach, mock } from "node:test";
+import assert from "node:assert";
+import { createNip07SigningAdapter } from "../../js/auth/signingAdapter.js";
+
+describe("createNip07SigningAdapter", () => {
+  let originalWindow;
+
+  beforeEach(() => {
+    // Preserve original window if it exists (for safety, though usually undefined in node)
+    if (typeof globalThis.window !== "undefined") {
+      originalWindow = globalThis.window;
+    }
+  });
+
+  afterEach(() => {
+    // Restore window
+    if (originalWindow) {
+      globalThis.window = originalWindow;
+    } else {
+      delete globalThis.window;
+    }
+  });
+
+  test("uses explicit extension if provided", async () => {
+    const mockExtension = {
+      getPublicKey: mock.fn(async () => "explicit_pubkey"),
+      signEvent: mock.fn(async (event) => ({ ...event, sig: "signature" })),
+    };
+
+    const adapter = createNip07SigningAdapter({ extension: mockExtension });
+
+    const pubkey = await adapter.getPubkey();
+    assert.strictEqual(pubkey, "explicit_pubkey");
+    assert.strictEqual(mockExtension.getPublicKey.mock.calls.length, 1);
+
+    const event = { id: "123" };
+    const signed = await adapter.signEvent(event);
+    assert.strictEqual(signed.sig, "signature");
+    assert.strictEqual(mockExtension.signEvent.mock.calls.length, 1);
+    assert.deepStrictEqual(mockExtension.signEvent.mock.calls[0].arguments[0], event);
+  });
+
+  test("falls back to window.nostr if no extension provided", async () => {
+    const mockWindowNostr = {
+      getPublicKey: mock.fn(async () => "window_pubkey"),
+      signEvent: mock.fn(async (event) => ({ ...event, sig: "window_sig" })),
+    };
+
+    globalThis.window = { nostr: mockWindowNostr };
+
+    const adapter = createNip07SigningAdapter();
+
+    const pubkey = await adapter.getPubkey();
+    assert.strictEqual(pubkey, "window_pubkey");
+    assert.strictEqual(mockWindowNostr.getPublicKey.mock.calls.length, 1);
+  });
+
+  test("throws error if no extension available", async () => {
+    globalThis.window = {}; // No nostr
+
+    const adapter = createNip07SigningAdapter();
+
+    await assert.rejects(
+      async () => adapter.getPubkey(),
+      { message: "NIP-07 extension unavailable." }
+    );
+
+    await assert.rejects(
+      async () => adapter.signEvent({}),
+      { message: "NIP-07 extension unavailable." }
+    );
+  });
+
+  test("prioritizes explicit extension over window.nostr", async () => {
+    const mockExplicit = {
+      getPublicKey: mock.fn(async () => "explicit"),
+    };
+    const mockWindow = {
+      getPublicKey: mock.fn(async () => "window"),
+    };
+
+    globalThis.window = { nostr: mockWindow };
+
+    const adapter = createNip07SigningAdapter({ extension: mockExplicit });
+    const pubkey = await adapter.getPubkey();
+
+    assert.strictEqual(pubkey, "explicit");
+    assert.strictEqual(mockExplicit.getPublicKey.mock.calls.length, 1);
+    assert.strictEqual(mockWindow.getPublicKey.mock.calls.length, 0);
+  });
+});