diff --git a/QA.md b/QA.md
index b88bb6d..2d36d54 100644
--- a/QA.md
+++ b/QA.md
@@ -36,8 +36,6 @@ The behaviors of the console are tested in [Console section](#consoles).
 
 #### Misc
 
-- [ ] <kbd>z</kbd><kbd>i</kbd>, <kbd>z</kbd><kbd>o</kbd>: zoom-in and zoom-out
-- [ ] <kbd>z</kbd><kbd>z</kbd>: set zoom level as default
 - [ ] <kbd>y</kbd>: yank current URL and show a message
 - [ ] <kbd>p</kbd>: open clipbord's URL in current tab
 - [ ] <kbd>P</kbd>: open clipbord's URL in new tab
diff --git a/e2e/ambassador/src/background/index.js b/e2e/ambassador/src/background/index.js
index 6425b54..5264c16 100644
--- a/e2e/ambassador/src/background/index.js
+++ b/e2e/ambassador/src/background/index.js
@@ -1,6 +1,6 @@
 import {
   WINDOWS_CREATE, WINDOWS_REMOVE, WINDOWS_GET,
-  TABS_CREATE, TABS_SELECT_AT,
+  TABS_CREATE, TABS_REMOVE, TABS_SELECT_AT, TABS_GET_ZOOM, TABS_SET_ZOOM,
   EVENT_KEYPRESS, EVENT_KEYDOWN, EVENT_KEYUP,
   SCROLL_GET, SCROLL_SET,
 } from '../shared/messages';
@@ -20,11 +20,17 @@ receiveContentMessage((message) => {
       url: message.url,
       windowId: message.windowId,
     });
+  case TABS_REMOVE:
+    return browser.tabs.remove(message.tabId);
   case TABS_SELECT_AT:
     return tabs.selectAt({
       windowId: message.windowId,
       index: message.index,
     });
+  case TABS_GET_ZOOM:
+    return browser.tabs.getZoom(message.tabId);
+  case TABS_SET_ZOOM:
+    return browser.tabs.setZoom(message.tabId, message.factor);
   case EVENT_KEYPRESS:
   case EVENT_KEYDOWN:
   case EVENT_KEYUP:
diff --git a/e2e/ambassador/src/client/tabs.js b/e2e/ambassador/src/client/tabs.js
index 6aaefbd..c7b1340 100644
--- a/e2e/ambassador/src/client/tabs.js
+++ b/e2e/ambassador/src/client/tabs.js
@@ -1,5 +1,5 @@
 import {
-  TABS_CREATE, TABS_SELECT_AT,
+  TABS_CREATE, TABS_SELECT_AT, TABS_GET_ZOOM, TABS_SET_ZOOM,
 } from '../shared/messages';
 import * as ipc from './ipc';
 
@@ -19,4 +19,19 @@ const selectAt = (windowId, index) => {
   });
 };
 
-export { create, selectAt };
+const getZoom = (tabId) => {
+  return ipc.send({
+    tabId,
+    type: TABS_GET_ZOOM,
+  });
+};
+
+const setZoom = (tabId, factor) => {
+  return ipc.send({
+    type: TABS_SET_ZOOM,
+    tabId,
+    factor,
+  });
+};
+
+export { create, selectAt, getZoom, setZoom };
diff --git a/e2e/ambassador/src/shared/messages.js b/e2e/ambassador/src/shared/messages.js
index 9fd1054..1fc47d2 100644
--- a/e2e/ambassador/src/shared/messages.js
+++ b/e2e/ambassador/src/shared/messages.js
@@ -5,6 +5,8 @@ const WINDOWS_REMOVE = 'windows.remove';
 const WINDOWS_GET = 'windows.get';
 const TABS_CREATE = 'tabs.create';
 const TABS_SELECT_AT = 'tabs.selectAt';
+const TABS_GET_ZOOM = 'tabs.get.zoom';
+const TABS_SET_ZOOM = 'tabs.set.zoom';
 const EVENT_KEYPRESS = 'event.keypress';
 const EVENT_KEYDOWN = 'event.keydown';
 const EVENT_KEYUP = 'event.keyup';
@@ -21,6 +23,8 @@ export {
 
   TABS_CREATE,
   TABS_SELECT_AT,
+  TABS_GET_ZOOM,
+  TABS_SET_ZOOM,
 
   EVENT_KEYPRESS,
   EVENT_KEYDOWN,
diff --git a/e2e/contents/zoom.test.js b/e2e/contents/zoom.test.js
new file mode 100644
index 0000000..c2e787f
--- /dev/null
+++ b/e2e/contents/zoom.test.js
@@ -0,0 +1,72 @@
+import { expect } from "chai";
+import * as windows from "../ambassador/src/client/windows";
+import * as tabs from "../ambassador/src/client/tabs";
+import * as keys from "../ambassador/src/client/keys";
+
+const SERVER_URL = "localhost:11111/";
+
+describe("tab test", () => {
+  let targetWindow;
+  let targetTab;
+
+  before(() => {
+    return windows.create(SERVER_URL).then((win) => {
+      targetWindow = win;
+    });
+  });
+
+  after(() => {
+    return windows.remove(targetWindow.id);
+  });
+
+  beforeEach(() => {
+    return tabs.create(targetWindow.id, SERVER_URL).then((tab) => {
+      targetTab = tab;
+    });
+  });
+
+  it('zooms-in by zi', () => {
+    let before;
+    return tabs.getZoom(targetTab.id).then((zoom) => {
+      before = zoom;
+      return keys.press(targetTab.id, 'z');
+    }).then(() => {
+      return keys.press(targetTab.id, 'i');
+    }).then(() => {
+      return tabs.getZoom(targetTab.id);
+    }).then((actual) => {
+      expect(actual).to.be.greaterThan(before);
+    });
+  });
+
+  it('zooms-in by zo', () => {
+    let before;
+    return tabs.getZoom(targetTab.id).then((zoom) => {
+      before = zoom;
+      return keys.press(targetTab.id, 'z');
+    }).then(() => {
+      return keys.press(targetTab.id, 'o');
+    }).then(() => {
+      return tabs.getZoom(targetTab.id);
+    }).then((actual) => {
+      expect(actual).to.be.lessThan(before);
+    });
+  });
+
+  it('zooms-in by zz', () => {
+    let before;
+    tabs.setZoom(targetTab.id, 1.5).then(() => {
+      return tabs.getZoom(targetTab.id);
+    }).then((zoom) => {
+      before = zoom;
+      return keys.press(targetTab.id, 'z');
+    }).then(() => {
+      return keys.press(targetTab.id, 'z');
+    }).then(() => {
+      return tabs.getZoom(targetTab.id);
+    }).then((actual) => {
+      expect(actual).to.be.lessThan(before);
+      expect(actual).to.be.be(1);
+    });
+  });
+});