diff --git a/tabby-core/src/services/hotkeys.service.ts b/tabby-core/src/services/hotkeys.service.ts
index 671178b2..d93ffa09 100644
--- a/tabby-core/src/services/hotkeys.service.ts
+++ b/tabby-core/src/services/hotkeys.service.ts
@@ -3,6 +3,7 @@ import { Observable, Subject } from 'rxjs'
 import { HotkeyDescription, HotkeyProvider } from '../api/hotkeyProvider'
 import { stringifyKeySequence, EventData } from './hotkeys.util'
 import { ConfigService } from './config.service'
+import { HostAppService, Platform } from '../api/hostApp'
 import { deprecate } from 'util'
 
 export interface PartialHotkeyMatch {
@@ -35,6 +36,7 @@ export class HotkeysService {
         private zone: NgZone,
         private config: ConfigService,
         @Inject(HotkeyProvider) private hotkeyProviders: HotkeyProvider[],
+        hostApp: HostAppService,
     ) {
         const events = ['keydown', 'keyup']
         events.forEach(event => {
@@ -43,6 +45,10 @@ export class HotkeysService {
                     this.pushKeystroke(event, nativeEvent)
                     this.processKeystrokes()
                     this.emitKeyEvent(nativeEvent)
+                    if (hostApp.platform === Platform.Web) {
+                        nativeEvent.preventDefault()
+                        nativeEvent.stopPropagation()
+                    }
                 }
             })
         })
diff --git a/tabby-settings/src/components/windowSettingsTab.component.pug b/tabby-settings/src/components/windowSettingsTab.component.pug
index 394305f4..39fe27df 100644
--- a/tabby-settings/src/components/windowSettingsTab.component.pug
+++ b/tabby-settings/src/components/windowSettingsTab.component.pug
@@ -9,6 +9,17 @@ h3.mb-3 Window
     )
         option(*ngFor='let theme of themes', [ngValue]='theme.name') {{theme.name}}
 
+
+.form-line(*ngIf='hostApp.platform === Platform.Web')
+    .header
+        .title Ask before closing the browser tab
+        .description Prevents accidental closing
+    toggle(
+        [(ngModel)]='config.store.web.preventAccidentalTabClosure',
+        (ngModelChange)='saveConfiguration()',
+    )
+
+
 .form-line(*ngIf='platform.supportsWindowControls')
     .header
         .title(*ngIf='hostApp.platform !== Platform.macOS') Acrylic background
diff --git a/tabby-web/package.json b/tabby-web/package.json
index 407ff604..d4294c1c 100644
--- a/tabby-web/package.json
+++ b/tabby-web/package.json
@@ -22,6 +22,7 @@
   "devDependencies": {
     "@vaadin/vaadin-context-menu": "^5.0.0",
     "bootstrap": "^4.1.3",
+    "bowser": "^2.11.0",
     "copy-text-to-clipboard": "^3.0.1"
   }
 }
diff --git a/tabby-web/src/config.ts b/tabby-web/src/config.ts
new file mode 100644
index 00000000..78530cf5
--- /dev/null
+++ b/tabby-web/src/config.ts
@@ -0,0 +1,10 @@
+import { ConfigProvider } from 'tabby-core'
+
+/** @hidden */
+export class WebConfigProvider extends ConfigProvider {
+    defaults = {
+        web: {
+            preventAccidentalTabClosure: true,
+        },
+    }
+}
diff --git a/tabby-web/src/index.ts b/tabby-web/src/index.ts
index fc846641..6fda15e4 100644
--- a/tabby-web/src/index.ts
+++ b/tabby-web/src/index.ts
@@ -1,6 +1,6 @@
 import { NgModule } from '@angular/core'
 import { CommonModule } from '@angular/common'
-import { HostAppService, HostWindowService, LogService, PlatformService, UpdaterService } from 'tabby-core'
+import { ConfigProvider, HostAppService, HostWindowService, LogService, PlatformService, UpdaterService } from 'tabby-core'
 
 import { WebPlatformService } from './platform'
 import { ConsoleLogService } from './services/log.service'
@@ -8,6 +8,7 @@ import { NullUpdaterService } from './services/updater.service'
 import { WebHostWindow } from './services/hostWindow.service'
 import { WebHostApp } from './services/hostApp.service'
 import { MessageBoxModalComponent } from './components/messageBoxModal.component'
+import { WebConfigProvider } from './config'
 
 import './styles.scss'
 
@@ -21,6 +22,7 @@ import './styles.scss'
         { provide: UpdaterService, useClass: NullUpdaterService },
         { provide: HostWindowService, useClass: WebHostWindow },
         { provide: HostAppService, useClass: WebHostApp },
+        { provide: ConfigProvider, useClass: WebConfigProvider, multi: true },
     ],
     declarations: [
         MessageBoxModalComponent,
diff --git a/tabby-web/src/services/hostApp.service.ts b/tabby-web/src/services/hostApp.service.ts
index e3fb8c9a..a95982c8 100644
--- a/tabby-web/src/services/hostApp.service.ts
+++ b/tabby-web/src/services/hostApp.service.ts
@@ -1,3 +1,4 @@
+import Bowser from 'bowser'
 import { Injectable, Injector } from '@angular/core'
 import { HostAppService, Platform } from 'tabby-core'
 
@@ -8,7 +9,8 @@ export class WebHostApp extends HostAppService {
     }
 
     get configPlatform (): Platform {
-        return Platform.Windows // TODO
+        const os = Bowser.parse(window.navigator.userAgent).os
+        return Platform[os.name ?? 'Windows'] ?? Platform.Windows
     }
 
     // Needed for injector metadata
diff --git a/tabby-web/src/services/hostWindow.service.ts b/tabby-web/src/services/hostWindow.service.ts
index 5e1c2267..c14b9a3c 100644
--- a/tabby-web/src/services/hostWindow.service.ts
+++ b/tabby-web/src/services/hostWindow.service.ts
@@ -1,14 +1,23 @@
 import { Injectable } from '@angular/core'
-import { HostWindowService } from 'tabby-core'
+import { ConfigService, HostWindowService } from 'tabby-core'
 
 @Injectable({ providedIn: 'root' })
 export class WebHostWindow extends HostWindowService {
     get isFullscreen (): boolean { return !!document.fullscreenElement }
 
-    constructor () {
+    constructor (
+        config: ConfigService,
+    ) {
         super()
         this.windowShown.next()
         this.windowFocused.next()
+
+        window.addEventListener('beforeunload', (event) => {
+            if (config.store.web.preventAccidentalTabClosure) {
+                event.preventDefault()
+                event.returnValue = 'Are you sure you want to close Tabby? You can disable this prompt in Settings -> Window.'
+            }
+        }
     }
 
     reload (): void {
diff --git a/tabby-web/yarn.lock b/tabby-web/yarn.lock
index e22b3d46..68e64557 100644
--- a/tabby-web/yarn.lock
+++ b/tabby-web/yarn.lock
@@ -160,6 +160,11 @@ bootstrap@^4.1.3:
   resolved "https://registry.yarnpkg.com/bootstrap/-/bootstrap-4.6.0.tgz#97b9f29ac98f98dfa43bf7468262d84392552fd7"
   integrity sha512-Io55IuQY3kydzHtbGvQya3H+KorS/M9rSNyfCGCg9WZ4pyT/lCxIlpJgG1GXW/PswzC84Tr2fBYi+7+jFVQQBw==
 
+bowser@^2.11.0:
+  version "2.11.0"
+  resolved "https://registry.yarnpkg.com/bowser/-/bowser-2.11.0.tgz#5ca3c35757a7aa5771500c70a73a9f91ef420a8f"
+  integrity sha512-AlcaJBi/pqqJBIQ8U9Mcpc9i8Aqxn88Skv5d+xBX006BY5u8N3mGLHa5Lgppa7L/HfwgwLgZ6NYs+Ag6uUmJRA==
+
 copy-text-to-clipboard@^3.0.1:
   version "3.0.1"
   resolved "https://registry.yarnpkg.com/copy-text-to-clipboard/-/copy-text-to-clipboard-3.0.1.tgz#8cbf8f90e0a47f12e4a24743736265d157bce69c"