diff --git a/tests/sendWebhook.test.js b/tests/sendWebhook.test.js
new file mode 100644
index 0000000..f788d50
--- /dev/null
+++ b/tests/sendWebhook.test.js
@@ -0,0 +1,177 @@
+const { sendWebhook } = require('../utils/utils');
+
+describe('sendWebhook', () => {
+  const mockBrowser = {
+    tabs: {
+      query: jest.fn(),
+    },
+    runtime: {
+      getBrowserInfo: jest.fn(),
+      getPlatformInfo: jest.fn(),
+    },
+    i18n: {
+      getMessage: jest.fn((key, ...args) => `${key} ${args.join(' ')}`.trim()),
+    },
+  };
+
+  const originalFetch = global.fetch;
+  const originalBrowser = global.browser;
+  const originalConsoleError = console.error;
+
+  beforeEach(() => {
+    global.fetch = jest.fn(() =>
+      Promise.resolve({
+        ok: true,
+        json: () => Promise.resolve({}),
+      })
+    );
+    global.browser = mockBrowser;
+    console.error = jest.fn();
+
+    // Default mock implementations
+    mockBrowser.tabs.query.mockResolvedValue([{
+      id: 1,
+      windowId: 1,
+      index: 0,
+      url: 'https://example.com',
+      title: 'Example Domain',
+      pinned: false,
+      audible: false,
+      mutedInfo: {},
+      incognito: false,
+      status: 'complete'
+    }]);
+    mockBrowser.runtime.getBrowserInfo.mockResolvedValue({ name: 'Firefox', version: '90.0' });
+    mockBrowser.runtime.getPlatformInfo.mockResolvedValue({ os: 'linux', arch: 'x86-64' });
+    mockBrowser.i18n.getMessage.mockClear();
+  });
+
+  afterEach(() => {
+    global.fetch = originalFetch;
+    global.browser = originalBrowser;
+    console.error = originalConsoleError;
+    jest.clearAllMocks();
+  });
+
+  test('should send test webhook', async () => {
+    const webhook = { url: 'https://test.com' };
+    await sendWebhook(webhook, true);
+
+    expect(global.fetch).toHaveBeenCalledWith(
+      webhook.url,
+      expect.objectContaining({
+        method: 'POST',
+        body: expect.stringContaining('"test":true'),
+      })
+    );
+  });
+
+  test('should send real webhook with tab info', async () => {
+    const webhook = { url: 'https://real.com' };
+    await sendWebhook(webhook, false);
+
+    expect(mockBrowser.tabs.query).toHaveBeenCalled();
+    expect(global.fetch).toHaveBeenCalledWith(
+      webhook.url,
+      expect.objectContaining({
+        method: 'POST',
+        body: expect.stringContaining('"title":"Example Domain"'),
+      })
+    );
+  });
+
+  test('should include custom headers', async () => {
+    const webhook = {
+      url: 'https://headers.com',
+      headers: [{ key: 'X-Custom', value: 'MyValue' }]
+    };
+    await sendWebhook(webhook, true);
+
+    expect(global.fetch).toHaveBeenCalledWith(
+      expect.any(String),
+      expect.objectContaining({
+        headers: expect.objectContaining({
+          'X-Custom': 'MyValue',
+          'Content-Type': 'application/json'
+        })
+      })
+    );
+  });
+
+  test('should support GET method', async () => {
+    const webhook = {
+      url: 'https://get.com',
+      method: 'GET'
+    };
+    await sendWebhook(webhook, true);
+
+    expect(global.fetch).toHaveBeenCalledWith(
+      expect.stringContaining('https://get.com/?payload='),
+      expect.objectContaining({
+        method: 'GET',
+        body: undefined
+      })
+    );
+  });
+
+  test('should replace placeholders in custom payload', async () => {
+    const webhook = {
+      url: 'https://custom.com',
+      customPayload: '{"text": "Page: {{tab.title}}", "id": {{tab.id}}}'
+    };
+    await sendWebhook(webhook, false);
+
+    expect(global.fetch).toHaveBeenCalledWith(
+      expect.any(String),
+      expect.objectContaining({
+        body: JSON.stringify({
+          text: "Page: Example Domain",
+          id: 1
+        })
+      })
+    );
+  });
+
+  test('should handle string replacements in JSON values correctly', async () => {
+     const webhook = {
+      url: 'https://custom.com',
+      customPayload: '{"browser": {{browser}}}'
+    };
+    await sendWebhook(webhook, false);
+
+    // The current implementation replaces {{browser}} with a stringified JSON string,
+    // so the resulting payload has "browser": "{\"name\":...}"
+    expect(global.fetch).toHaveBeenCalledWith(
+      expect.any(String),
+      expect.objectContaining({
+        body: expect.stringContaining('"browser":"{\\"name\\":\\"Firefox\\",\\"version\\":\\"90.0\\"}"')
+      })
+    );
+  });
+
+  test('should throw error if no active tab found', async () => {
+    mockBrowser.tabs.query.mockResolvedValue([]);
+
+    await expect(sendWebhook({ url: 'https://fail.com' }, false))
+      .rejects.toThrow('popupErrorNoActiveTab');
+  });
+
+  test('should throw error on fetch failure', async () => {
+    global.fetch.mockResolvedValue({
+      ok: false,
+      status: 500
+    });
+
+    await expect(sendWebhook({ url: 'https://fail.com' }, true))
+      .rejects.toThrow('popupErrorHttp 500');
+  });
+
+  test('should throw error on invalid custom payload JSON', async () => {
+    const webhook = {
+      url: 'https://custom.com',
+      customPayload: '{invalid_json}'
+    };
+    await expect(sendWebhook(webhook, false))
+      .rejects.toThrow('popupErrorCustomPayloadJsonParseError');
+  });
+});