diff --git a/packages/clipper/src/background/background.ts b/packages/clipper/src/background/background.ts
index 096d149d77b..cc47a5b7c2c 100644
--- a/packages/clipper/src/background/background.ts
+++ b/packages/clipper/src/background/background.ts
@@ -5,6 +5,20 @@ import packageInfo from '../../package.json'
 
 const isFirefox = navigator.userAgent.indexOf('Firefox/') !== -1
 
+const openClipperAuthPanel = async (pane: 'sign-in' | 'register') => {
+  const popupPath = await browserAction.getPopup({})
+  const url = new URL(popupPath, runtime.getURL('/'))
+  url.searchParams.set('route', 'extension')
+  url.searchParams.set('pane', pane)
+
+  await windows.create({
+    type: 'detached_panel',
+    url: url.toString(),
+    width: 350,
+    height: 300,
+  })
+}
+
 const openPopupAndClipSelection = async (payload: ClipPayload) => {
   await storage.local.set({ clip: payload })
 
@@ -33,6 +47,8 @@ runtime.onMessage.addListener(async (message: RuntimeMessage) => {
       return
     }
     void openPopupAndClipSelection(message.payload)
+  } else if (message.type === RuntimeMessageTypes.OpenClipperAuthPanel) {
+    await openClipperAuthPanel(message.pane)
   } else if (message.type === RuntimeMessageTypes.CaptureVisibleTab) {
     return await tabs.captureVisibleTab(undefined, {
       format: 'png',
diff --git a/packages/clipper/src/manifest.v2.json b/packages/clipper/src/manifest.v2.json
index 162e565cf7d..2f88f46b531 100644
--- a/packages/clipper/src/manifest.v2.json
+++ b/packages/clipper/src/manifest.v2.json
@@ -27,7 +27,7 @@
   "browser_specific_settings": {
     "gecko": {
       "id": "{9f917dfe-accd-4d3a-9685-33c3ac0ca643}",
-      "strict_min_version": "48.0"
+      "strict_min_version": "150.0"
     }
   }
 }
diff --git a/packages/clipper/src/manifest.v3.json b/packages/clipper/src/manifest.v3.json
index 76ce7108f06..ee78fdaf3c4 100644
--- a/packages/clipper/src/manifest.v3.json
+++ b/packages/clipper/src/manifest.v3.json
@@ -28,7 +28,7 @@
   "browser_specific_settings": {
     "gecko": {
       "id": "{9f917dfe-accd-4d3a-9685-33c3ac0ca643}",
-      "strict_min_version": "48.0"
+      "strict_min_version": "150.0"
     }
   }
 }
diff --git a/packages/clipper/src/types/message.ts b/packages/clipper/src/types/message.ts
index b365203f635..1b986d22023 100644
--- a/packages/clipper/src/types/message.ts
+++ b/packages/clipper/src/types/message.ts
@@ -10,6 +10,7 @@ export const RuntimeMessageTypes = {
   ToggleScreenshotMode: 'toggle-screenshot-mode',
   CaptureVisibleTab: 'capture-visible-tab',
   RunHttpRequest: 'run-http-request',
+  OpenClipperAuthPanel: 'open-clipper-auth-panel',
 } as const
 
 export type RuntimeMessageType = (typeof RuntimeMessageTypes)[keyof typeof RuntimeMessageTypes]
@@ -33,6 +34,7 @@ export type RuntimeMessageReturnTypes = {
   [RuntimeMessageTypes.StartNodeSelection]: void
   [RuntimeMessageTypes.ToggleScreenshotMode]: void
   [RuntimeMessageTypes.RunHttpRequest]: void
+  [RuntimeMessageTypes.OpenClipperAuthPanel]: void
 }
 
 export type RuntimeMessage =
@@ -48,11 +50,16 @@ export type RuntimeMessage =
       type: typeof RuntimeMessageTypes.ToggleScreenshotMode
       enabled: boolean
     }
+  | {
+      type: typeof RuntimeMessageTypes.OpenClipperAuthPanel
+      pane: 'sign-in' | 'register'
+    }
   | {
       type: Exclude<
         RuntimeMessageType,
         | MessagesWithClipPayload
         | typeof RuntimeMessageTypes.ToggleScreenshotMode
         | typeof RuntimeMessageTypes.RunHttpRequest
+        | typeof RuntimeMessageTypes.OpenClipperAuthPanel
       >
     }
diff --git a/packages/clipper/src/utils/sendMessageToActiveTab.ts b/packages/clipper/src/utils/sendMessageToActiveTab.ts
index a7e5130de35..ec633d6130c 100644
--- a/packages/clipper/src/utils/sendMessageToActiveTab.ts
+++ b/packages/clipper/src/utils/sendMessageToActiveTab.ts
@@ -4,11 +4,15 @@ import { RuntimeMessage, RuntimeMessageReturnTypes } from '../types/message'
 export default async function sendMessageToActiveTab<T extends RuntimeMessage>(
   message: T,
 ): Promise<RuntimeMessageReturnTypes[T['type']] | undefined> {
-  const [activeTab] = await tabs.query({ active: true, currentWindow: true, windowType: 'normal' })
+  const [activeTab] = await tabs.query({ active: true, lastFocusedWindow: true })
 
-  if (!activeTab || !activeTab.id) {
+  if (!activeTab?.id) {
     return
   }
 
-  return await tabs.sendMessage(activeTab.id, message)
+  try {
+    return await tabs.sendMessage(activeTab.id, message)
+  } catch {
+    return
+  }
 }
diff --git a/packages/snjs/lib/Application/Application.ts b/packages/snjs/lib/Application/Application.ts
index 79977ffc904..876b4e73e08 100644
--- a/packages/snjs/lib/Application/Application.ts
+++ b/packages/snjs/lib/Application/Application.ts
@@ -82,6 +82,7 @@ import {
   CreateEncryptedBackupFile,
   WebSocketsService,
   PreferencesServiceEvent,
+  AuthenticatorManager,
 } from '@standardnotes/services'
 import {
   SNNote,
@@ -955,6 +956,10 @@ export class SNApplication implements ApplicationInterface, AppGroupManagedAppli
     return this.dependencies.get<AddAuthenticator>(TYPES.AddAuthenticator)
   }
 
+  fetchAuthenticatorRegistrationOptions(): Promise<Record<string, unknown> | null> {
+    return this.dependencies.get<AuthenticatorManager>(TYPES.AuthenticatorManager).generateRegistrationOptions()
+  }
+
   get listAuthenticators(): ListAuthenticators {
     return this.dependencies.get<ListAuthenticators>(TYPES.ListAuthenticators)
   }
diff --git a/packages/snjs/lib/Domain/UseCase/AddAuthenticator/AddAuthenticator.ts b/packages/snjs/lib/Domain/UseCase/AddAuthenticator/AddAuthenticator.ts
index d8bceb528ee..9a7990b525f 100644
--- a/packages/snjs/lib/Domain/UseCase/AddAuthenticator/AddAuthenticator.ts
+++ b/packages/snjs/lib/Domain/UseCase/AddAuthenticator/AddAuthenticator.ts
@@ -31,7 +31,8 @@ export class AddAuthenticator implements UseCaseInterface<void> {
       )
     }
 
-    const registrationOptions = await this.authenticatorClient.generateRegistrationOptions()
+    const registrationOptions =
+      dto.registrationOptions ?? (await this.authenticatorClient.generateRegistrationOptions())
     if (registrationOptions === null) {
       return Result.fail('Could not generate authenticator registration options')
     }
diff --git a/packages/snjs/lib/Domain/UseCase/AddAuthenticator/AddAuthenticatorDTO.ts b/packages/snjs/lib/Domain/UseCase/AddAuthenticator/AddAuthenticatorDTO.ts
index 77aa3d8bd42..c47fd81d3e5 100644
--- a/packages/snjs/lib/Domain/UseCase/AddAuthenticator/AddAuthenticatorDTO.ts
+++ b/packages/snjs/lib/Domain/UseCase/AddAuthenticator/AddAuthenticatorDTO.ts
@@ -1,4 +1,6 @@
 export interface AddAuthenticatorDTO {
   userUuid: string
   authenticatorName: string
+  /** When provided, skips the server round-trip so WebAuthn can run in the same user gesture. */
+  registrationOptions?: Record<string, unknown>
 }
diff --git a/packages/web/src/javascripts/Application/WebApplication.ts b/packages/web/src/javascripts/Application/WebApplication.ts
index b3ac644b147..7751183cad3 100644
--- a/packages/web/src/javascripts/Application/WebApplication.ts
+++ b/packages/web/src/javascripts/Application/WebApplication.ts
@@ -29,6 +29,7 @@ import { action, computed, makeObservable, observable } from 'mobx'
 import { startAuthentication, startRegistration } from '@simplewebauthn/browser'
 import { PanelResizedData } from '@/Types/PanelResizedData'
 import { getBlobFromBase64, isDesktopApplication, isDev } from '@/Utils'
+import { prepareWebAuthnRegistrationOptions } from '@/Utils/prepareWebAuthnRegistrationOptions'
 import {
   ArchiveManager,
   AutolockService,
@@ -128,9 +129,10 @@ export class WebApplication extends SNApplication implements WebApplicationInter
         deviceInterface.environment === Environment.Mobile ? 250 : ApplicationOptionsDefaults.sleepBetweenBatches,
       allowMultipleSelection: deviceInterface.environment !== Environment.Mobile,
       allowNoteSelectionStatePersistence: deviceInterface.environment !== Environment.Mobile,
-      u2fAuthenticatorRegistrationPromptFunction: startRegistration as unknown as (
-        registrationOptions: Record<string, unknown>,
-      ) => Promise<Record<string, unknown>>,
+      u2fAuthenticatorRegistrationPromptFunction: ((registrationOptions: Record<string, unknown>) =>
+        startRegistration(
+          prepareWebAuthnRegistrationOptions(registrationOptions) as unknown as Parameters<typeof startRegistration>[0],
+        )) as unknown as (registrationOptions: Record<string, unknown>) => Promise<Record<string, unknown>>,
       u2fAuthenticatorVerificationPromptFunction: startAuthentication as unknown as (
         authenticationOptions: Record<string, unknown>,
       ) => Promise<Record<string, unknown>>,
diff --git a/packages/web/src/javascripts/Components/ChallengeModal/U2FPrompt.tsx b/packages/web/src/javascripts/Components/ChallengeModal/U2FPrompt.tsx
index 87de464b32f..848e968a4ec 100644
--- a/packages/web/src/javascripts/Components/ChallengeModal/U2FPrompt.tsx
+++ b/packages/web/src/javascripts/Components/ChallengeModal/U2FPrompt.tsx
@@ -1,15 +1,17 @@
-import { Username } from '@standardnotes/snjs'
+import { Environment, Username } from '@standardnotes/snjs'
 import { ChallengePrompt } from '@standardnotes/services'
-import { RefObject, useState } from 'react'
+import { RefObject, useCallback, useState } from 'react'
 import { c } from 'ttag'
 
 import { WebApplication } from '@/Application/WebApplication'
+import { IS_FIREFOX } from '@/Components/SuperEditor/Lexical/Shared/environment'
 
 import Button from '../Button/Button'
 import Icon from '../Icon/Icon'
 
 import { InputValue } from './InputValue'
 import U2FPromptIframeContainer from './U2FPromptIframeContainer'
+import U2FPromptFirefoxNative from './U2FPromptFirefoxNative'
 import { isAndroid } from '@standardnotes/ui-services'
 
 type Props = {
@@ -24,11 +26,31 @@ const U2FPrompt = ({ application, onValueChange, prompt, buttonRef, contextData
   const [authenticatorResponse, setAuthenticatorResponse] = useState<Record<string, unknown> | null>(null)
   const [error, setError] = useState('')
 
+  const handleNativeResponse = useCallback(
+    (response: Record<string, unknown>) => {
+      onValueChange(response, prompt)
+    },
+    [onValueChange, prompt],
+  )
+
   if (!application.isFullU2FClient && !isAndroid()) {
+    const apiHost = application.getHost.execute().getValue() || window.defaultSyncServer
+
+    if (application.environment === Environment.Clipper && IS_FIREFOX) {
+      return (
+        <U2FPromptFirefoxNative
+          contextData={contextData}
+          apiHost={apiHost}
+          buttonRef={buttonRef}
+          onResponse={handleNativeResponse}
+        />
+      )
+    }
+
     return (
       <U2FPromptIframeContainer
         contextData={contextData}
-        apiHost={application.getHost.execute().getValue() || window.defaultSyncServer}
+        apiHost={apiHost}
         onResponse={(response) => {
           onValueChange(response, prompt)
         }}
diff --git a/packages/web/src/javascripts/Components/ChallengeModal/U2FPromptFirefoxNative.tsx b/packages/web/src/javascripts/Components/ChallengeModal/U2FPromptFirefoxNative.tsx
new file mode 100644
index 00000000000..ed4d7a4a6f8
--- /dev/null
+++ b/packages/web/src/javascripts/Components/ChallengeModal/U2FPromptFirefoxNative.tsx
@@ -0,0 +1,81 @@
+import { log, LoggingDomain } from '@/Logging'
+import { getU2fRelyingPartyId } from '@/Constants/U2FConstants'
+import { startAuthentication } from '@simplewebauthn/browser'
+import type { PublicKeyCredentialRequestOptionsJSON } from '@simplewebauthn/typescript-types'
+import { RefObject, useCallback, useState } from 'react'
+import { c } from 'ttag'
+
+import Button from '../Button/Button'
+
+type Props = {
+  contextData?: Record<string, unknown>
+  onResponse: (response: Record<string, unknown>) => void
+  apiHost: string
+  buttonRef: RefObject<HTMLButtonElement>
+}
+
+const U2FPromptFirefoxNative = ({ contextData, onResponse, apiHost, buttonRef }: Props) => {
+  const [pending, setPending] = useState(false)
+  const [error, setError] = useState('')
+
+  const authenticateWithSecurityKey = useCallback(async () => {
+    const username = (contextData as { username: string } | undefined)?.username
+    if (!username) {
+      setError(c('B1.Account.SignIn.Error').t`No username provided`)
+      return
+    }
+
+    setPending(true)
+    setError('')
+
+    try {
+      const response = await fetch(`${apiHost}/v1/authenticators/generate-authentication-options`, {
+        method: 'POST',
+        headers: { 'Content-Type': 'application/json' },
+        body: JSON.stringify({ username }),
+      })
+
+      const jsonResponse = await response.json()
+      if (!jsonResponse.data?.options) {
+        throw new Error(c('B1.Account.SignIn.Error').t`No options returned from server`)
+      }
+
+      const options = jsonResponse.data.options as PublicKeyCredentialRequestOptionsJSON
+
+      const rpId = getU2fRelyingPartyId(apiHost, options)
+
+      log(LoggingDomain.U2F, 'Starting native WebAuthn authentication', {
+        username,
+        apiHost,
+        rpId,
+      })
+
+      const assertionResponse = await startAuthentication({
+        ...options,
+        rpId,
+      })
+
+      log(LoggingDomain.U2F, 'Native WebAuthn authentication completed', { id: assertionResponse.id })
+
+      onResponse(assertionResponse as unknown as Record<string, unknown>)
+    } catch (authError) {
+      setError(authError instanceof Error ? authError.message : String(authError))
+      console.error(authError)
+    } finally {
+      setPending(false)
+    }
+  }, [contextData, apiHost, onResponse])
+
+  return (
+    <div className="min-w-76">
+      {error && <div className="text-danger">{error}</div>}
+      <Button primary fullWidth onClick={authenticateWithSecurityKey} disabled={pending} ref={buttonRef}>
+        {pending
+          ? c('B1.Account.SignIn.Status').t`Waiting for security key...`
+          : c('B5.SecuritySync.Challenge.Action').t`Authenticate Device`}
+      </Button>
+    </div>
+  )
+}
+
+export default U2FPromptFirefoxNative
diff --git a/packages/web/src/javascripts/Components/ClipperView/ClipperView.tsx b/packages/web/src/javascripts/Components/ClipperView/ClipperView.tsx
index e3cb780e9fb..52cc06aed2d 100644
--- a/packages/web/src/javascripts/Components/ClipperView/ClipperView.tsx
+++ b/packages/web/src/javascripts/Components/ClipperView/ClipperView.tsx
@@ -39,6 +39,18 @@ import LinkedItemBubble from '../LinkedItems/LinkedItemBubble'
 import StyledTooltip from '../StyledTooltip/StyledTooltip'
 import MenuSwitchButtonItem from '../Menu/MenuSwitchButtonItem'
 import Spinner from '../Spinner/Spinner'
+import { IS_FIREFOX } from '@/Components/SuperEditor/Lexical/Shared/environment'
+
+const getAuthPaneFromUrl = () => {
+  const pane = new URLSearchParams(window.location.search).get('pane')
+  if (pane === 'sign-in') {
+    return AccountMenuPane.SignIn
+  }
+  if (pane === 'register') {
+    return AccountMenuPane.Register
+  }
+  return undefined
+}
 
 const ClipperView = ({ applicationGroup }: { applicationGroup: WebApplicationGroup }) => {
   const application = useApplication()
@@ -54,6 +66,8 @@ const ClipperView = ({ applicationGroup }: { applicationGroup: WebApplicationGro
       })
       .catch(console.error)
   }, [])
+  const isDetachedPanel = (currentWindow?.type as string | undefined) === 'detached_panel'
+  const isFirefoxAuthPanel = IS_FIREFOX && getAuthPaneFromUrl() !== undefined
   const isFirefoxPopup = !!currentWindow && currentWindow.type === 'popup' && currentWindow.incognito === false
 
   const [user, setUser] = useState(() => application.sessions.getUser())
@@ -74,6 +88,16 @@ const ClipperView = ({ applicationGroup }: { applicationGroup: WebApplicationGro
     return application.addEventObserver(async (event) => {
       switch (event) {
         case ApplicationEvent.SignedIn:
+          setUser(application.sessions.getUser())
+          setIsEntitled(
+            application.features.getFeatureStatus(
+              NativeFeatureIdentifier.create(NativeFeatureIdentifier.TYPES.Clipper).getValue(),
+            ) === FeatureStatus.Entitled,
+          )
+          if (isFirefoxAuthPanel) {
+            window.close()
+          }
+          break
         case ApplicationEvent.SignedOut:
         case ApplicationEvent.UserRolesChanged:
           setUser(application.sessions.getUser())
@@ -126,15 +150,37 @@ const ClipperView = ({ applicationGroup }: { applicationGroup: WebApplicationGro
     void application.setPreference(PrefKey.ClipperDefaultTagUuid, undefined)
   }, [application])
 
-  const [menuPane, setMenuPane] = useState<AccountMenuPane>()
+  const [menuPane, setMenuPane] = useState<AccountMenuPane | undefined>(getAuthPaneFromUrl)
+
+  const openFirefoxAuthPanel = useCallback(async (pane: 'sign-in' | 'register') => {
+    try {
+      await runtime.sendMessage({ type: RuntimeMessageTypes.OpenClipperAuthPanel, pane })
+    } catch (error) {
+      console.error(error)
+      setMenuPane(pane === 'sign-in' ? AccountMenuPane.SignIn : AccountMenuPane.Register)
+      return
+    }
+
+    window.close()
+  }, [])
 
   const activateRegisterPane = useCallback(() => {
+    if (IS_FIREFOX && !isFirefoxAuthPanel && !isDetachedPanel) {
+      void openFirefoxAuthPanel('register')
+      return
+    }
+
     setMenuPane(AccountMenuPane.Register)
-  }, [setMenuPane])
+  }, [isDetachedPanel, isFirefoxAuthPanel, openFirefoxAuthPanel])
 
   const activateSignInPane = useCallback(() => {
+    if (IS_FIREFOX && !isFirefoxAuthPanel && !isDetachedPanel) {
+      void openFirefoxAuthPanel('sign-in')
+      return
+    }
+
     setMenuPane(AccountMenuPane.SignIn)
-  }, [setMenuPane])
+  }, [isDetachedPanel, isFirefoxAuthPanel, openFirefoxAuthPanel])
 
   const showSignOutConfirmation = useCallback(async () => {
     if (
@@ -155,7 +201,7 @@ const ClipperView = ({ applicationGroup }: { applicationGroup: WebApplicationGro
     void sendMessageToActiveTab({
       type: RuntimeMessageTypes.ToggleScreenshotMode,
       enabled: isScreenshotMode,
-    })
+    }).catch(() => undefined)
   }, [isScreenshotMode])
 
   const [hasSelection, setHasSelection] = useState(false)
@@ -323,16 +369,26 @@ const ClipperView = ({ applicationGroup }: { applicationGroup: WebApplicationGro
   }
 
   if (!user) {
-    return menuPane ? (
-      <div className="py-1">
-        <MenuPaneSelector
-          mainApplicationGroup={applicationGroup}
-          menuPane={menuPane}
-          setMenuPane={setMenuPane}
-          closeMenu={() => setMenuPane(undefined)}
-        />
-      </div>
-    ) : (
+    if (menuPane || isFirefoxAuthPanel) {
+      return (
+        <div className="py-1">
+          <MenuPaneSelector
+            mainApplicationGroup={applicationGroup}
+            menuPane={menuPane ?? AccountMenuPane.SignIn}
+            setMenuPane={(pane) => {
+              if (isFirefoxAuthPanel && pane === AccountMenuPane.GeneralMenu) {
+                window.close()
+                return
+              }
+              setMenuPane(pane)
+            }}
+            closeMenu={() => (isFirefoxAuthPanel ? window.close() : setMenuPane(undefined))}
+          />
+        </div>
+      )
+    }
+
+    return (
       <Menu a11yLabel={c('B1.Account.Session.Label').t`User account menu`}>
         <MenuItem onClick={activateRegisterPane}>
           <Icon type="user" className="mr-2 h-6 w-6 text-neutral md:h-5 md:w-5" />
diff --git a/packages/web/src/javascripts/Components/Preferences/Panes/Security/U2F/U2FAddDeviceView.tsx b/packages/web/src/javascripts/Components/Preferences/Panes/Security/U2F/U2FAddDeviceView.tsx
index b32d968a491..4ea5ea722fb 100644
--- a/packages/web/src/javascripts/Components/Preferences/Panes/Security/U2F/U2FAddDeviceView.tsx
+++ b/packages/web/src/javascripts/Components/Preferences/Panes/Security/U2F/U2FAddDeviceView.tsx
@@ -1,4 +1,4 @@
-import { FunctionComponent, useCallback, useState } from 'react'
+import { FunctionComponent, useCallback, useEffect, useState } from 'react'
 import { observer } from 'mobx-react-lite'
 import { AddAuthenticator } from '@standardnotes/snjs'
 
@@ -19,6 +19,27 @@ const U2FAddDeviceView: FunctionComponent<Props> = ({ addAuthenticator, onDevice
 
   const [deviceName, setDeviceName] = useState('')
   const [errorMessage, setErrorMessage] = useState('')
+  const [registrationOptions, setRegistrationOptions] = useState<Record<string, unknown> | null>(null)
+  const [isLoadingOptions, setIsLoadingOptions] = useState(true)
+
+  useEffect(() => {
+    let isActive = true
+
+    void application.fetchAuthenticatorRegistrationOptions().then((options) => {
+      if (!isActive) {
+        return
+      }
+      setRegistrationOptions(options)
+      setIsLoadingOptions(false)
+      if (options === null) {
+        setErrorMessage(c('B6.Preferences.Security.Error').t`Could not prepare security key registration`)
+      }
+    })
+
+    return () => {
+      isActive = false
+    }
+  }, [application])
 
   const handleDeviceNameChange = useCallback((deviceName: string) => {
     setDeviceName(deviceName)
@@ -30,6 +51,11 @@ const U2FAddDeviceView: FunctionComponent<Props> = ({ addAuthenticator, onDevice
       return
     }
 
+    if (!registrationOptions) {
+      setErrorMessage(c('B6.Preferences.Security.Error').t`Could not prepare security key registration`)
+      return
+    }
+
     const user = application.sessions.getUser()
     if (user === undefined) {
       setErrorMessage(c('B6.Preferences.Security.Error').t`User not found`)
@@ -39,6 +65,7 @@ const U2FAddDeviceView: FunctionComponent<Props> = ({ addAuthenticator, onDevice
     const authenticatorAddedOrError = await addAuthenticator.execute({
       userUuid: user.uuid,
       authenticatorName: deviceName,
+      registrationOptions,
     })
     if (authenticatorAddedOrError.isFailed()) {
       setErrorMessage(authenticatorAddedOrError.getError())
@@ -47,7 +74,15 @@ const U2FAddDeviceView: FunctionComponent<Props> = ({ addAuthenticator, onDevice
 
     onDeviceAddingModalToggle(false)
     await onDeviceAdded()
-  }, [deviceName, setErrorMessage, application, addAuthenticator, onDeviceAddingModalToggle, onDeviceAdded])
+  }, [
+    deviceName,
+    registrationOptions,
+    setErrorMessage,
+    application,
+    addAuthenticator,
+    onDeviceAddingModalToggle,
+    onDeviceAdded,
+  ])
 
   const closeModal = () => {
     onDeviceAddingModalToggle(false)
@@ -77,6 +112,7 @@ const U2FAddDeviceView: FunctionComponent<Props> = ({ addAuthenticator, onDevice
           type: 'primary',
           onClick: handleAddDeviceClick,
           mobileSlot: 'right',
+          disabled: isLoadingOptions || registrationOptions === null,
         },
       ]}
     >
diff --git a/packages/web/src/javascripts/Constants/U2FConstants.ts b/packages/web/src/javascripts/Constants/U2FConstants.ts
new file mode 100644
index 00000000000..64e4dbc7f75
--- /dev/null
+++ b/packages/web/src/javascripts/Constants/U2FConstants.ts
@@ -0,0 +1,28 @@
+/** Relying party ID used when registering and authenticating hardware keys for Standard Notes. */
+export const U2F_RELYING_PARTY_ID = 'app.standardnotes.com'
+
+/**
+ * Stable WebAuthn origin for the Firefox clipper extension (SHA-256 of gecko.id, a–p encoded).
+ * Must be included in the auth server's U2F_EXPECTED_ORIGIN allowlist.
+ * @see https://developer.mozilla.org/en-US/docs/Mozilla/Add-ons/WebExtensions/Use_the_web_authn_api
+ */
+export const FIREFOX_CLIPPER_WEBAUTHN_ORIGIN =
+  'moz-extension://mbmeiccjaghdhkomcnlbapkpmhjgcjdonnphcmpgbgnlpbepegcaeomhoinfmflc'
+
+export function isLocalU2fApiHost(apiHost: string): boolean {
+  try {
+    const hostname = new URL(apiHost).hostname
+    return hostname === 'localhost' || hostname === '127.0.0.1'
+  } catch {
+    return false
+  }
+}
+
+/** Prod clipper always uses app.standardnotes.com; local servers use their configured rpId. */
+export function getU2fRelyingPartyId(apiHost: string, serverOptions?: { rpId?: string }): string {
+  if (isLocalU2fApiHost(apiHost)) {
+    return serverOptions?.rpId ?? new URL(apiHost).hostname
+  }
+
+  return U2F_RELYING_PARTY_ID
+}
diff --git a/packages/web/src/javascripts/Utils/prepareWebAuthnRegistrationOptions.ts b/packages/web/src/javascripts/Utils/prepareWebAuthnRegistrationOptions.ts
new file mode 100644
index 00000000000..287213f45e1
--- /dev/null
+++ b/packages/web/src/javascripts/Utils/prepareWebAuthnRegistrationOptions.ts
@@ -0,0 +1,26 @@
+import { isDev } from '@/Utils'
+
+/** Align rpId with the page hostname for local WebAuthn development. */
+export function prepareWebAuthnRegistrationOptions(options: Record<string, unknown>): Record<string, unknown> {
+  if (!isDev) {
+    return options
+  }
+
+  const hostname = window.location.hostname
+  if (hostname !== 'localhost' && hostname !== '127.0.0.1') {
+    return options
+  }
+
+  const rp = options.rp as { id?: string; name?: string } | undefined
+  if (!rp) {
+    return options
+  }
+
+  return {
+    ...options,
+    rp: {
+      ...rp,
+      id: hostname,
+    },
+  }
+}