diff --git a/src/content/di.ts b/src/content/di.ts
index e18806a..63103a1 100644
--- a/src/content/di.ts
+++ b/src/content/di.ts
@@ -2,6 +2,7 @@
 
 import { AddonEnabledRepositoryImpl } from './repositories/AddonEnabledRepository';
 import { AddonIndicatorClientImpl } from './client/AddonIndicatorClient';
+import { AddressRepositoryImpl } from './repositories/AddressRepository';
 import { ClipboardRepositoryImpl } from './repositories/ClipboardRepository';
 import { ConsoleClientImpl } from './client/ConsoleClient';
 import { ConsoleFramePresenterImpl } from './presenters/ConsoleFramePresenter';
@@ -31,6 +32,7 @@ import { container } from 'tsyringe';
 container.register('FollowMasterClient', { useValue: new FollowMasterClientImpl(window.top) });
 container.register('AddonEnabledRepository', { useClass: AddonEnabledRepositoryImpl });
 container.register('AddonIndicatorClient', { useClass: AddonIndicatorClientImpl });
+container.register('AddressRepository', { useClass: AddressRepositoryImpl });
 container.register('ClipboardRepository', { useClass: ClipboardRepositoryImpl });
 container.register('ConsoleClient', { useClass: ConsoleClientImpl });
 container.register('ConsoleFramePresenter', { useClass: ConsoleFramePresenterImpl });
diff --git a/src/content/repositories/AddressRepository.ts b/src/content/repositories/AddressRepository.ts
new file mode 100644
index 0000000..6f9487b
--- /dev/null
+++ b/src/content/repositories/AddressRepository.ts
@@ -0,0 +1,9 @@
+export default interface AddressRepository {
+  getCurrentURL(): URL
+}
+
+export class AddressRepositoryImpl implements AddressRepository {
+  getCurrentURL(): URL {
+    return new URL(window.location.href);
+  }
+}
diff --git a/src/content/usecases/KeymapUseCase.ts b/src/content/usecases/KeymapUseCase.ts
index 495f6d0..67d667d 100644
--- a/src/content/usecases/KeymapUseCase.ts
+++ b/src/content/usecases/KeymapUseCase.ts
@@ -6,6 +6,7 @@ import * as operations from '../../shared/operations';
 import Keymaps from '../../shared/settings/Keymaps';
 import Key from '../../shared/settings/Key';
 import KeySequence from '../../shared/settings/KeySequence';
+import AddressRepository from '../repositories/AddressRepository';
 
 type KeymapEntityMap = Map<KeySequence, operations.Operation>;
 
@@ -25,11 +26,19 @@ export default class KeymapUseCase {
 
     @inject('AddonEnabledRepository')
     private addonEnabledRepository: AddonEnabledRepository,
+
+    @inject('AddressRepository')
+    private addressRepository: AddressRepository,
   ) {
   }
 
   nextOp(key: Key): operations.Operation | null {
     let sequence = this.repository.enqueueKey(key);
+    if (sequence.length() === 1 && this.blacklistKey(key)) {
+      // ignore if the input starts with black list keys
+      this.repository.clear();
+      return null;
+    }
 
     let keymaps = this.keymapEntityMap();
     let matched = Array.from(keymaps.keys()).filter(
@@ -71,4 +80,10 @@ export default class KeymapUseCase {
     ) as [KeySequence, operations.Operation][];
     return new Map<KeySequence, operations.Operation>(entries);
   }
+
+  private blacklistKey(key: Key): boolean {
+    let url = this.addressRepository.getCurrentURL();
+    let blacklist = this.settingRepository.get().blacklist;
+    return blacklist.includeKey(url, key);
+  }
 }
diff --git a/test/content/usecases/KeymapUseCase.test.ts b/test/content/usecases/KeymapUseCase.test.ts
new file mode 100644
index 0000000..5f2feba
--- /dev/null
+++ b/test/content/usecases/KeymapUseCase.test.ts
@@ -0,0 +1,133 @@
+import KeymapUseCase from '../../../src/content/usecases/KeymapUseCase';
+import {expect} from 'chai';
+import SettingRepository from "../../../src/content/repositories/SettingRepository";
+import Settings from "../../../src/shared/settings/Settings";
+import AddonEnabledRepository from "../../../src/content/repositories/AddonEnabledRepository";
+import {KeymapRepositoryImpl} from "../../../src/content/repositories/KeymapRepository";
+import Key from "../../../src/shared/settings/Key";
+import AddressRepository from "../../../src/content/repositories/AddressRepository";
+
+class MockSettingRepository implements SettingRepository {
+  constructor(
+    private readonly settings: Settings,
+  ) {
+  }
+
+  get(): Settings {
+    return this.settings;
+  }
+
+  set(_setting: Settings): void {
+    throw new Error('TODO');
+  }
+}
+
+class MockAddonEnabledRepository implements AddonEnabledRepository {
+  constructor(
+    private readonly enabled: boolean,
+  ) {
+  }
+
+  get(): boolean {
+    return this.enabled;
+  }
+
+  set(_on: boolean): void {
+    throw new Error('TODO');
+  }
+}
+
+class MockAddressRepository implements AddressRepository {
+  constructor(
+    private url: URL,
+  ) {
+  }
+
+  getCurrentURL(): URL {
+    return this.url;
+  }
+}
+
+
+describe('KeymapUseCase', () => {
+  it('returns matched operation', () => {
+    let settings = Settings.fromJSON({
+      keymaps: {
+        k: {type: 'scroll.vertically', count: -1},
+        j: {type: 'scroll.vertically', count: 1},
+        gg: {type: 'scroll.top'},
+      },
+    });
+    let sut = new KeymapUseCase(
+      new KeymapRepositoryImpl(),
+      new MockSettingRepository(settings),
+      new MockAddonEnabledRepository(true),
+      new MockAddressRepository(new URL('https://example.com')),
+    );
+
+    expect(sut.nextOp(Key.fromMapKey('k'))).to.deep.equal({type: 'scroll.vertically', count: -1});
+    expect(sut.nextOp(Key.fromMapKey('j'))).to.deep.equal({type: 'scroll.vertically', count: 1});
+    expect(sut.nextOp(Key.fromMapKey('g'))).to.be.null;
+    expect(sut.nextOp(Key.fromMapKey('g'))).to.deep.equal({type: 'scroll.top'});
+    expect(sut.nextOp(Key.fromMapKey('z'))).to.be.null;
+  });
+
+  it('returns only ADDON_ENABLE and ADDON_TOGGLE_ENABLED operation', () => {
+    let settings = Settings.fromJSON({
+      keymaps: {
+        k: {type: 'scroll.vertically', count: -1},
+        a: {type: 'addon.enable'},
+        b: {type: 'addon.toggle.enabled'},
+      },
+    });
+    let sut = new KeymapUseCase(
+      new KeymapRepositoryImpl(),
+      new MockSettingRepository(settings),
+      new MockAddonEnabledRepository(false),
+      new MockAddressRepository(new URL('https://example.com')),
+    );
+
+    expect(sut.nextOp(Key.fromMapKey('k'))).to.be.null;
+    expect(sut.nextOp(Key.fromMapKey('a'))).to.deep.equal({type: 'addon.enable'});
+    expect(sut.nextOp(Key.fromMapKey('b'))).to.deep.equal({type: 'addon.toggle.enabled'});
+  });
+
+  it('blocks keys in the partial blacklist', () => {
+    let settings = Settings.fromJSON({
+      keymaps: {
+        k: {type: 'scroll.vertically', count: -1},
+        j: {type: 'scroll.vertically', count: 1},
+        gg: {"type": "scroll.top"},
+        G: {"type": "scroll.bottom"},
+      },
+      blacklist: [
+        { url: "example.com", keys: ['g'] },
+        { url: "example.org", keys: ['<S-G>'] }
+      ],
+    });
+
+    let sut = new KeymapUseCase(
+      new KeymapRepositoryImpl(),
+      new MockSettingRepository(settings),
+      new MockAddonEnabledRepository(true),
+      new MockAddressRepository(new URL('https://example.com')),
+    );
+
+    expect(sut.nextOp(Key.fromMapKey('k'))).to.deep.equal({type: 'scroll.vertically', count: -1});
+    expect(sut.nextOp(Key.fromMapKey('j'))).to.deep.equal({type: 'scroll.vertically', count: 1});
+    expect(sut.nextOp(Key.fromMapKey('g'))).to.be.null;
+    expect(sut.nextOp(Key.fromMapKey('g'))).to.be.null;
+    expect(sut.nextOp(Key.fromMapKey('G'))).to.deep.equal({type: 'scroll.bottom'});
+
+    sut = new KeymapUseCase(
+      new KeymapRepositoryImpl(),
+      new MockSettingRepository(settings),
+      new MockAddonEnabledRepository(true),
+      new MockAddressRepository(new URL('https://example.org')),
+    );
+
+    expect(sut.nextOp(Key.fromMapKey('g'))).to.be.null;
+    expect(sut.nextOp(Key.fromMapKey('g'))).to.deep.equal({type: 'scroll.top'});
+    expect(sut.nextOp(Key.fromMapKey('G'))).to.be.null;
+  });
+});