diff --git a/.yarn/cache/@simplewebauthn-browser-npm-7.0.0-93e13e1065-eb8d7e2d92.zip b/.yarn/cache/@simplewebauthn-browser-npm-7.0.0-93e13e1065-eb8d7e2d92.zip
deleted file mode 100644
index 34e817595..000000000
Binary files a/.yarn/cache/@simplewebauthn-browser-npm-7.0.0-93e13e1065-eb8d7e2d92.zip and /dev/null differ
diff --git a/.yarn/cache/@simplewebauthn-browser-npm-7.1.0-356ca6f81a-925e266075.zip b/.yarn/cache/@simplewebauthn-browser-npm-7.1.0-356ca6f81a-925e266075.zip
new file mode 100644
index 000000000..9a8da658d
Binary files /dev/null and b/.yarn/cache/@simplewebauthn-browser-npm-7.1.0-356ca6f81a-925e266075.zip differ
diff --git a/packages/snjs/lib/Application/Application.ts b/packages/snjs/lib/Application/Application.ts
index dca909fdb..6cb91ffb0 100644
--- a/packages/snjs/lib/Application/Application.ts
+++ b/packages/snjs/lib/Application/Application.ts
@@ -79,7 +79,6 @@ import {
   DecryptedItemInterface,
   EncryptedItemInterface,
   Environment,
-  HistoryEntry,
   ItemStream,
   Platform,
 } from '@standardnotes/models'
@@ -90,7 +89,7 @@ import { SNLog } from '../Log'
 import { ChallengeResponse, ListedClientInterface } from '../Services'
 import { ApplicationConstructorOptions, FullyResolvedApplicationOptions } from './Options/ApplicationOptions'
 import { ApplicationOptionsDefaults } from './Options/Defaults'
-import { LegacySession, MapperInterface, Session, UseCaseInterface } from '@standardnotes/domain-core'
+import { LegacySession, MapperInterface, Session } from '@standardnotes/domain-core'
 import { SessionStorageMapper } from '@Lib/Services/Mapping/SessionStorageMapper'
 import { LegacySessionStorageMapper } from '@Lib/Services/Mapping/LegacySessionStorageMapper'
 import { SignInWithRecoveryCodes } from '@Lib/Domain/UseCase/SignInWithRecoveryCodes/SignInWithRecoveryCodes'
@@ -102,7 +101,6 @@ import { DeleteAuthenticator } from '@Lib/Domain/UseCase/DeleteAuthenticator/Del
 import { ListRevisions } from '@Lib/Domain/UseCase/ListRevisions/ListRevisions'
 import { GetRevision } from '@Lib/Domain/UseCase/GetRevision/GetRevision'
 import { DeleteRevision } from '@Lib/Domain/UseCase/DeleteRevision/DeleteRevision'
-import { RevisionMetadata } from '@Lib/Domain/Revision/RevisionMetadata'
 import { GetAuthenticatorAuthenticationResponse } from '@Lib/Domain/UseCase/GetAuthenticatorAuthenticationResponse/GetAuthenticatorAuthenticationResponse'
 
 /** How often to automatically sync, in milliseconds */
@@ -266,39 +264,39 @@ export class SNApplication implements ApplicationInterface, AppGroupManagedAppli
     return this.subscriptionManager
   }
 
-  get signInWithRecoveryCodes(): UseCaseInterface<void> {
+  get signInWithRecoveryCodes(): SignInWithRecoveryCodes {
     return this._signInWithRecoveryCodes
   }
 
-  get getRecoveryCodes(): UseCaseInterface<string> {
+  get getRecoveryCodes(): GetRecoveryCodes {
     return this._getRecoveryCodes
   }
 
-  get addAuthenticator(): UseCaseInterface<void> {
+  get addAuthenticator(): AddAuthenticator {
     return this._addAuthenticator
   }
 
-  get listAuthenticators(): UseCaseInterface<Array<{ id: string; name: string }>> {
+  get listAuthenticators(): ListAuthenticators {
     return this._listAuthenticators
   }
 
-  get deleteAuthenticator(): UseCaseInterface<void> {
+  get deleteAuthenticator(): DeleteAuthenticator {
     return this._deleteAuthenticator
   }
 
-  get getAuthenticatorAuthenticationResponse(): UseCaseInterface<Record<string, unknown>> {
+  get getAuthenticatorAuthenticationResponse(): GetAuthenticatorAuthenticationResponse {
     return this._getAuthenticatorAuthenticationResponse
   }
 
-  get listRevisions(): UseCaseInterface<Array<RevisionMetadata>> {
+  get listRevisions(): ListRevisions {
     return this._listRevisions
   }
 
-  get getRevision(): UseCaseInterface<HistoryEntry> {
+  get getRevision(): GetRevision {
     return this._getRevision
   }
 
-  get deleteRevision(): UseCaseInterface<void> {
+  get deleteRevision(): DeleteRevision {
     return this._deleteRevision
   }
 
diff --git a/packages/snjs/lib/Domain/UseCase/UseCaseContainerInterface.ts b/packages/snjs/lib/Domain/UseCase/UseCaseContainerInterface.ts
index 4399a41e6..06c72a5a4 100644
--- a/packages/snjs/lib/Domain/UseCase/UseCaseContainerInterface.ts
+++ b/packages/snjs/lib/Domain/UseCase/UseCaseContainerInterface.ts
@@ -1,16 +1,21 @@
-import { HistoryEntry } from '@standardnotes/models'
-import { UseCaseInterface } from '@standardnotes/domain-core'
-
-import { RevisionMetadata } from '../Revision/RevisionMetadata'
+import { AddAuthenticator } from './AddAuthenticator/AddAuthenticator'
+import { GetRecoveryCodes } from './GetRecoveryCodes/GetRecoveryCodes'
+import { SignInWithRecoveryCodes } from './SignInWithRecoveryCodes/SignInWithRecoveryCodes'
+import { ListAuthenticators } from './ListAuthenticators/ListAuthenticators'
+import { DeleteAuthenticator } from './DeleteAuthenticator/DeleteAuthenticator'
+import { GetAuthenticatorAuthenticationResponse } from './GetAuthenticatorAuthenticationResponse/GetAuthenticatorAuthenticationResponse'
+import { ListRevisions } from './ListRevisions/ListRevisions'
+import { GetRevision } from './GetRevision/GetRevision'
+import { DeleteRevision } from './DeleteRevision/DeleteRevision'
 
 export interface UseCaseContainerInterface {
-  get signInWithRecoveryCodes(): UseCaseInterface<void>
-  get getRecoveryCodes(): UseCaseInterface<string>
-  get addAuthenticator(): UseCaseInterface<void>
-  get listAuthenticators(): UseCaseInterface<Array<{ id: string; name: string }>>
-  get deleteAuthenticator(): UseCaseInterface<void>
-  get getAuthenticatorAuthenticationResponse(): UseCaseInterface<Record<string, unknown>>
-  get listRevisions(): UseCaseInterface<Array<RevisionMetadata>>
-  get getRevision(): UseCaseInterface<HistoryEntry>
-  get deleteRevision(): UseCaseInterface<void>
+  get signInWithRecoveryCodes(): SignInWithRecoveryCodes
+  get getRecoveryCodes(): GetRecoveryCodes
+  get addAuthenticator(): AddAuthenticator
+  get listAuthenticators(): ListAuthenticators
+  get deleteAuthenticator(): DeleteAuthenticator
+  get getAuthenticatorAuthenticationResponse(): GetAuthenticatorAuthenticationResponse
+  get listRevisions(): ListRevisions
+  get getRevision(): GetRevision
+  get deleteRevision(): DeleteRevision
 }
diff --git a/packages/snjs/lib/Domain/index.ts b/packages/snjs/lib/Domain/index.ts
index a5ff50e6f..d1fe689aa 100644
--- a/packages/snjs/lib/Domain/index.ts
+++ b/packages/snjs/lib/Domain/index.ts
@@ -1,2 +1,18 @@
 export * from './Revision/Revision'
 export * from './Revision/RevisionMetadata'
+export * from './UseCase/AddAuthenticator/AddAuthenticator'
+export * from './UseCase/AddAuthenticator/AddAuthenticatorDTO'
+export * from './UseCase/DeleteAuthenticator/DeleteAuthenticator'
+export * from './UseCase/DeleteAuthenticator/DeleteAuthenticatorDTO'
+export * from './UseCase/DeleteRevision/DeleteRevision'
+export * from './UseCase/DeleteRevision/DeleteRevisionDTO'
+export * from './UseCase/GetAuthenticatorAuthenticationResponse/GetAuthenticatorAuthenticationResponse'
+export * from './UseCase/GetAuthenticatorAuthenticationResponse/GetAuthenticatorAuthenticationResponseDTO'
+export * from './UseCase/GetRecoveryCodes/GetRecoveryCodes'
+export * from './UseCase/GetRevision/GetRevision'
+export * from './UseCase/GetRevision/GetRevisionDTO'
+export * from './UseCase/ListAuthenticators/ListAuthenticators'
+export * from './UseCase/ListRevisions/ListRevisions'
+export * from './UseCase/ListRevisions/ListRevisionsDTO'
+export * from './UseCase/SignInWithRecoveryCodes/SignInWithRecoveryCodes'
+export * from './UseCase/SignInWithRecoveryCodes/SignInWithRecoveryCodesDTO'
diff --git a/packages/ui-services/src/Route/Params/AppViewRouteParams.ts b/packages/ui-services/src/Route/Params/AppViewRouteParams.ts
new file mode 100644
index 000000000..b191b1148
--- /dev/null
+++ b/packages/ui-services/src/Route/Params/AppViewRouteParams.ts
@@ -0,0 +1,3 @@
+export const ValidAppViewRoutes = ['u2f'] as const
+
+export type AppViewRouteParam = typeof ValidAppViewRoutes[number]
diff --git a/packages/ui-services/src/Route/RootQueryParam.ts b/packages/ui-services/src/Route/RootQueryParam.ts
index 216029a11..fc0943f53 100644
--- a/packages/ui-services/src/Route/RootQueryParam.ts
+++ b/packages/ui-services/src/Route/RootQueryParam.ts
@@ -4,4 +4,5 @@ export enum RootQueryParam {
   DemoToken = 'demo-token',
   AcceptSubscriptionInvite = 'accept-subscription-invite',
   UserRequest = 'user-request',
+  AppViewRoute = 'route',
 }
diff --git a/packages/ui-services/src/Route/RouteParser.ts b/packages/ui-services/src/Route/RouteParser.ts
index 83cc4fb78..ade6df172 100644
--- a/packages/ui-services/src/Route/RouteParser.ts
+++ b/packages/ui-services/src/Route/RouteParser.ts
@@ -1,5 +1,6 @@
 import { UserRequestType } from '@standardnotes/common'
 import { PreferenceId } from './../Preferences/PreferenceId'
+import { AppViewRouteParam, ValidAppViewRoutes } from './Params/AppViewRouteParams'
 import { DemoParams } from './Params/DemoParams'
 import { OnboardingParams } from './Params/OnboardingParams'
 import { PurchaseParams } from './Params/PurchaseParams'
@@ -78,6 +79,18 @@ export class RouteParser implements RouteParserInterface {
     }
   }
 
+  get appViewRouteParam(): AppViewRouteParam | undefined {
+    this.checkForProperRouteType(RouteType.AppViewRoute)
+
+    const appViewRoute = this.searchParams.get(RootQueryParam.AppViewRoute) as AppViewRouteParam
+
+    if (!ValidAppViewRoutes.includes(appViewRoute)) {
+      return
+    }
+
+    return this.searchParams.get(RootQueryParam.AppViewRoute) as AppViewRouteParam
+  }
+
   private checkForProperRouteType(type: RouteType): void {
     if (this.parsedType !== type) {
       throw new Error('Accessing invalid params')
@@ -99,6 +112,7 @@ export class RouteParser implements RouteParserInterface {
       [RootQueryParam.DemoToken, RouteType.Demo],
       [RootQueryParam.AcceptSubscriptionInvite, RouteType.AcceptSubscriptionInvite],
       [RootQueryParam.UserRequest, RouteType.UserRequest],
+      [RootQueryParam.AppViewRoute, RouteType.AppViewRoute],
     ])
 
     for (const rootQueryParam of rootQueryParametersMap.keys()) {
diff --git a/packages/ui-services/src/Route/RouteParserInterface.ts b/packages/ui-services/src/Route/RouteParserInterface.ts
index ddc01ac81..61bf3e3a8 100644
--- a/packages/ui-services/src/Route/RouteParserInterface.ts
+++ b/packages/ui-services/src/Route/RouteParserInterface.ts
@@ -1,3 +1,4 @@
+import { AppViewRouteParam } from './Params/AppViewRouteParams'
 import { DemoParams } from './Params/DemoParams'
 import { OnboardingParams } from './Params/OnboardingParams'
 import { PurchaseParams } from './Params/PurchaseParams'
@@ -13,5 +14,6 @@ export interface RouteParserInterface {
   get onboardingParams(): OnboardingParams
   get subscriptionInviteParams(): SubscriptionInviteParams
   get userRequestParams(): UserRequestParams
+  get appViewRouteParam(): AppViewRouteParam | undefined
   get type(): RouteType
 }
diff --git a/packages/ui-services/src/Route/RouteType.ts b/packages/ui-services/src/Route/RouteType.ts
index 5b2fe79a3..e577f14d6 100644
--- a/packages/ui-services/src/Route/RouteType.ts
+++ b/packages/ui-services/src/Route/RouteType.ts
@@ -5,5 +5,6 @@ export enum RouteType {
   AcceptSubscriptionInvite = 'accept-subscription-invite',
   UserRequest = 'user-request',
   Demo = 'demo',
+  AppViewRoute = 'route',
   None = 'none',
 }
diff --git a/packages/web/package.json b/packages/web/package.json
index 88e9b8567..cc3df8e6f 100644
--- a/packages/web/package.json
+++ b/packages/web/package.json
@@ -38,6 +38,7 @@
     "@reach/listbox": "^0.18.0",
     "@reach/tooltip": "^0.18.0",
     "@reach/visually-hidden": "^0.18.0",
+    "@simplewebauthn/browser": "^7.1.0",
     "@standardnotes/authenticator": "^2.3.9",
     "@standardnotes/autobiography-theme": "^1.2.7",
     "@standardnotes/bold-editor": "^1.6.4",
diff --git a/packages/web/src/javascripts/App.tsx b/packages/web/src/javascripts/App.tsx
index 99bd8cd10..6044f82ec 100644
--- a/packages/web/src/javascripts/App.tsx
+++ b/packages/web/src/javascripts/App.tsx
@@ -36,6 +36,8 @@ import { WebApplication } from './Application/Application'
 import { createRoot, Root } from 'react-dom/client'
 import { ElementIds } from './Constants/ElementIDs'
 import { setDefaultMonospaceFont } from './setDefaultMonospaceFont'
+import { RouteParser, RouteType } from '@standardnotes/ui-services'
+import U2FAuthIframe from './Components/U2FAuthIframe/U2FAuthIframe'
 
 let keyCount = 0
 const getKey = () => {
@@ -71,6 +73,13 @@ const startApplication: StartApplication = async function startApplication(
 
     setDefaultMonospaceFont(device.platform)
 
+    const route = new RouteParser(window.location.href)
+
+    if (route.type === RouteType.AppViewRoute && route.appViewRouteParam === 'u2f') {
+      root.render(<U2FAuthIframe />)
+      return
+    }
+
     root.render(
       <ApplicationGroupView
         key={getKey()}
diff --git a/packages/web/src/javascripts/Application/Application.ts b/packages/web/src/javascripts/Application/Application.ts
index cf2cb23c8..c229b0225 100644
--- a/packages/web/src/javascripts/Application/Application.ts
+++ b/packages/web/src/javascripts/Application/Application.ts
@@ -430,6 +430,14 @@ export class WebApplication extends SNApplication implements WebApplicationInter
     this.getViewControllerManager().accountMenuController.setShow(false)
   }
 
+  /**
+   * Full U2F clients are only web browser clients. They support adding and removing keys as well as authentication.
+   * The desktop and mobile clients cannot support adding keys.
+   */
+  get isFullU2FClient(): boolean {
+    return this.environment === Environment.Web
+  }
+
   geDefaultEditorIdentifier(currentTag?: SNTag): EditorIdentifier {
     return (
       currentTag?.preferences?.editorIdentifier ||
diff --git a/packages/web/src/javascripts/Components/ChallengeModal/U2FPrompt.tsx b/packages/web/src/javascripts/Components/ChallengeModal/U2FPrompt.tsx
index c381f17f9..c62bd31c0 100644
--- a/packages/web/src/javascripts/Components/ChallengeModal/U2FPrompt.tsx
+++ b/packages/web/src/javascripts/Components/ChallengeModal/U2FPrompt.tsx
@@ -4,6 +4,7 @@ import { RefObject, useState } from 'react'
 import Button from '../Button/Button'
 import Icon from '../Icon/Icon'
 import { InputValue } from './InputValue'
+import U2FPromptIframeContainer from './U2FPromptIframeContainer'
 
 type Props = {
   application: WebApplication
@@ -17,6 +18,18 @@ const U2FPrompt = ({ application, onValueChange, prompt, buttonRef, contextData
   const [authenticatorResponse, setAuthenticatorResponse] = useState<Record<string, unknown> | null>(null)
   const [error, setError] = useState('')
 
+  if (!application.isFullU2FClient) {
+    return (
+      <U2FPromptIframeContainer
+        contextData={contextData}
+        apiHost={application.getHost() || window.defaultSyncServer}
+        onResponse={(response) => {
+          onValueChange(response, prompt)
+        }}
+      />
+    )
+  }
+
   return (
     <div className="min-w-76">
       {error && <div className="text-red-500">{error}</div>}
@@ -27,18 +40,18 @@ const U2FPrompt = ({ application, onValueChange, prompt, buttonRef, contextData
         onClick={async () => {
           if (!contextData || contextData.username === undefined) {
             setError('No username provided')
-
             return
           }
 
           const authenticatorResponseOrError = await application.getAuthenticatorAuthenticationResponse.execute({
-            username: contextData.username,
+            username: contextData.username as string,
           })
+
           if (authenticatorResponseOrError.isFailed()) {
             setError(authenticatorResponseOrError.getError())
-
             return
           }
+
           const authenticatorResponse = authenticatorResponseOrError.getValue()
 
           setAuthenticatorResponse(authenticatorResponse)
diff --git a/packages/web/src/javascripts/Components/ChallengeModal/U2FPromptIframeContainer.tsx b/packages/web/src/javascripts/Components/ChallengeModal/U2FPromptIframeContainer.tsx
new file mode 100644
index 000000000..549dd2534
--- /dev/null
+++ b/packages/web/src/javascripts/Components/ChallengeModal/U2FPromptIframeContainer.tsx
@@ -0,0 +1,66 @@
+import { log, LoggingDomain } from '@/Logging'
+import { isDev } from '@/Utils'
+import { useEffect, useRef } from 'react'
+
+type Props = {
+  contextData?: Record<string, unknown>
+  onResponse: (response: string) => void
+  apiHost: string
+}
+
+const U2F_IFRAME_ORIGIN = isDev ? 'http://localhost:3001/?route=u2f' : 'https://app.standardnotes.com/?route=u2f'
+
+const U2FPromptIframeContainer = ({ contextData, onResponse, apiHost }: Props) => {
+  const iframeRef = useRef<HTMLIFrameElement>(null)
+
+  useEffect(() => {
+    const messageHandler = (event: MessageEvent) => {
+      log(LoggingDomain.U2F, 'Native client received message', event)
+      const eventDoesNotComeFromU2FIFrame = event.origin !== new URL(U2F_IFRAME_ORIGIN).origin
+      if (eventDoesNotComeFromU2FIFrame) {
+        log(
+          LoggingDomain.U2F,
+          'Not sending data to U2F iframe; origin does not match',
+          event.origin,
+          new URL(U2F_IFRAME_ORIGIN).origin,
+        )
+        return
+      }
+
+      if (event.data.mountedAuthView) {
+        if (iframeRef.current?.contentWindow) {
+          log(LoggingDomain.U2F, 'Sending contextData to U2F iframe', contextData)
+          iframeRef.current.contentWindow.postMessage(
+            { username: (contextData as Record<string, unknown>).username, apiHost },
+            U2F_IFRAME_ORIGIN,
+          )
+        }
+        return
+      }
+
+      if (event.data.assertionResponse) {
+        log(LoggingDomain.U2F, 'Received assertion response from U2F iframe', event.data.assertionResponse)
+        onResponse(event.data.assertionResponse)
+      }
+    }
+
+    window.addEventListener('message', messageHandler)
+
+    return () => {
+      window.removeEventListener('message', messageHandler)
+    }
+  }, [contextData, onResponse, apiHost])
+
+  return (
+    <iframe
+      ref={iframeRef}
+      src={U2F_IFRAME_ORIGIN}
+      className="h-40 w-full"
+      title="U2F"
+      allow="publickey-credentials-get"
+      id="u2f"
+    />
+  )
+}
+
+export default U2FPromptIframeContainer
diff --git a/packages/web/src/javascripts/Components/Input/DecoratedInput.tsx b/packages/web/src/javascripts/Components/Input/DecoratedInput.tsx
index 8771ca16b..8e8061049 100644
--- a/packages/web/src/javascripts/Components/Input/DecoratedInput.tsx
+++ b/packages/web/src/javascripts/Components/Input/DecoratedInput.tsx
@@ -1,5 +1,5 @@
 import { classNames } from '@standardnotes/utils'
-import { forwardRef, Fragment, Ref } from 'react'
+import { forwardRef, Fragment, KeyboardEventHandler, Ref, useCallback } from 'react'
 import { DecoratedInputProps } from './DecoratedInputProps'
 
 const getClassNames = (hasLeftDecorations: boolean, hasRightDecorations: boolean, roundedFull?: boolean) => {
@@ -31,6 +31,7 @@ const DecoratedInput = forwardRef(
       onFocus,
       onKeyDown,
       onKeyUp,
+      onEnter,
       placeholder = '',
       right,
       type = 'text',
@@ -38,6 +39,7 @@ const DecoratedInput = forwardRef(
       value,
       defaultValue,
       roundedFull,
+      autofocus = false,
     }: DecoratedInputProps,
     ref: Ref<HTMLInputElement>,
   ) => {
@@ -45,6 +47,16 @@ const DecoratedInput = forwardRef(
     const hasRightDecorations = Boolean(right?.length)
     const computedClassNames = getClassNames(hasLeftDecorations, hasRightDecorations, roundedFull)
 
+    const handleKeyUp: KeyboardEventHandler = useCallback(
+      (e) => {
+        if (e.key === 'Enter') {
+          onEnter?.()
+        }
+        onKeyUp?.(e)
+      },
+      [onKeyUp, onEnter],
+    )
+
     return (
       <div
         className={classNames(
@@ -63,6 +75,7 @@ const DecoratedInput = forwardRef(
 
         <input
           autoComplete={autocomplete ? 'on' : 'off'}
+          autoFocus={autofocus}
           className={`${computedClassNames.input} ${disabled ? computedClassNames.disabled : ''} ${className?.input}`}
           data-lpignore={type !== 'password' ? true : false}
           disabled={disabled}
@@ -71,7 +84,7 @@ const DecoratedInput = forwardRef(
           onChange={(e) => onChange && onChange((e.target as HTMLInputElement).value)}
           onFocus={onFocus}
           onKeyDown={onKeyDown}
-          onKeyUp={onKeyUp}
+          onKeyUp={handleKeyUp}
           placeholder={placeholder}
           ref={ref}
           title={title}
diff --git a/packages/web/src/javascripts/Components/Input/DecoratedInputProps.ts b/packages/web/src/javascripts/Components/Input/DecoratedInputProps.ts
index 8df855f2e..15c42d99b 100644
--- a/packages/web/src/javascripts/Components/Input/DecoratedInputProps.ts
+++ b/packages/web/src/javascripts/Components/Input/DecoratedInputProps.ts
@@ -2,6 +2,7 @@ import { FocusEventHandler, KeyboardEventHandler, ReactNode } from 'react'
 
 export type DecoratedInputProps = {
   autocomplete?: boolean
+  autofocus?: boolean
   spellcheck?: boolean
   className?: {
     container?: string
@@ -17,6 +18,7 @@ export type DecoratedInputProps = {
   onFocus?: FocusEventHandler
   onKeyDown?: KeyboardEventHandler
   onKeyUp?: KeyboardEventHandler
+  onEnter?: () => void
   placeholder?: string
   right?: ReactNode[]
   title?: string
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 d5f19118e..0d36f4630 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
@@ -1,6 +1,6 @@
 import { FunctionComponent, useCallback, useState } from 'react'
 import { observer } from 'mobx-react-lite'
-import { UseCaseInterface } from '@standardnotes/snjs'
+import { AddAuthenticator } from '@standardnotes/snjs'
 
 import DecoratedInput from '@/Components/Input/DecoratedInput'
 import { UserProvider } from '@/Components/Preferences/Providers'
@@ -9,7 +9,7 @@ import { MutuallyExclusiveMediaQueryBreakpoints, useMediaQuery } from '@/Hooks/u
 
 type Props = {
   userProvider: UserProvider
-  addAuthenticator: UseCaseInterface<void>
+  addAuthenticator: AddAuthenticator
   onDeviceAddingModalToggle: (show: boolean) => void
   onDeviceAdded: () => Promise<void>
 }
@@ -82,11 +82,22 @@ const U2FAddDeviceView: FunctionComponent<Props> = ({
         },
       ]}
     >
-      <div className="w-25 h-25 flex items-center justify-center bg-info">...Some Cool Device Picture Here...</div>
-      <div className="flex flex-grow flex-col gap-2">
-        <DecoratedInput className={{ container: 'w-92 ml-4' }} value={deviceName} onChange={handleDeviceNameChange} />
+      <div className="flex px-4 py-4">
+        <div className="ml-4 flex flex-grow flex-col gap-1">
+          <label htmlFor="u2f-device-name" className="mb-2 text-sm font-semibold">
+            Device Name
+          </label>
+          <DecoratedInput
+            autofocus
+            id="u2f-device-name"
+            className={{ container: 'w-92' }}
+            value={deviceName}
+            onChange={handleDeviceNameChange}
+            onEnter={handleAddDeviceClick}
+          />
+          {errorMessage && <div className="mt-1.5 text-danger">{errorMessage}</div>}
+        </div>
       </div>
-      {errorMessage && <div className="text-error">{errorMessage}</div>}
     </Modal>
   )
 }
diff --git a/packages/web/src/javascripts/Components/Preferences/Panes/Security/U2F/U2FView/U2FDescription.tsx b/packages/web/src/javascripts/Components/Preferences/Panes/Security/U2F/U2FView/U2FDescription.tsx
index c625a8942..16eb9c354 100644
--- a/packages/web/src/javascripts/Components/Preferences/Panes/Security/U2F/U2FView/U2FDescription.tsx
+++ b/packages/web/src/javascripts/Components/Preferences/Panes/Security/U2F/U2FView/U2FDescription.tsx
@@ -3,17 +3,27 @@ import { observer } from 'mobx-react-lite'
 
 import { Text } from '@/Components/Preferences/PreferencesComponents/Content'
 import { UserProvider } from '@/Components/Preferences/Providers'
+import { useApplication } from '@/Components/ApplicationProvider'
 
 type Props = {
   userProvider: UserProvider
 }
 
 const U2FDescription: FunctionComponent<Props> = ({ userProvider }) => {
+  const application = useApplication()
+
   if (userProvider.getUser() === undefined) {
     return <Text>Sign in or register for an account to configure U2F.</Text>
   }
 
-  return <Text>Authenticate with a U2F hardware device.</Text>
+  return (
+    <div>
+      <Text>Authenticate with a U2F hardware device such as Yubikey.</Text>
+      {!application.isFullU2FClient && (
+        <Text className="italic">Please visit the web app in order to add a U2F Device.</Text>
+      )}
+    </div>
+  )
 }
 
 export default observer(U2FDescription)
diff --git a/packages/web/src/javascripts/Components/Preferences/Panes/Security/U2F/U2FView/U2FDevicesList.tsx b/packages/web/src/javascripts/Components/Preferences/Panes/Security/U2F/U2FView/U2FDevicesList.tsx
index 22c8c45e3..9de4bb648 100644
--- a/packages/web/src/javascripts/Components/Preferences/Panes/Security/U2F/U2FView/U2FDevicesList.tsx
+++ b/packages/web/src/javascripts/Components/Preferences/Panes/Security/U2F/U2FView/U2FDevicesList.tsx
@@ -1,9 +1,10 @@
 import { FunctionComponent, useCallback } from 'react'
 import { observer } from 'mobx-react-lite'
 
-import { Text } from '@/Components/Preferences/PreferencesComponents/Content'
+import { Subtitle } from '@/Components/Preferences/PreferencesComponents/Content'
 import { WebApplication } from '@/Application/Application'
 import Button from '@/Components/Button/Button'
+import Icon from '@/Components/Icon/Icon'
 
 type Props = {
   application: WebApplication
@@ -31,24 +32,25 @@ const U2FDevicesList: FunctionComponent<Props> = ({ application, devices, onErro
   )
 
   return (
-    <div className="flex flex-row items-center">
+    <div>
       {devices.length > 0 && (
-        <div className="flex flex-grow flex-col">
-          <div>
-            <Text>Devices:</Text>
+        <>
+          <Subtitle>Devices</Subtitle>
+          <div className="flex flex-grow flex-col divide-y divide-border">
+            {devices.map((device) => (
+              <div className="flex items-center py-2" key={`device-${device.id}`}>
+                <Icon type="security" />
+                <div className="ml-2 mr-auto text-sm">{device.name}</div>
+                <Button
+                  small
+                  key={device.id}
+                  label="Delete"
+                  onClick={async () => handleDeleteButtonOnClick(device.id)}
+                ></Button>
+              </div>
+            ))}
           </div>
-          {devices.map((device) => (
-            <div key="device-{device.id}">
-              <Text>{device.name}</Text>
-              <Button
-                key={device.id}
-                primary={true}
-                label="Delete"
-                onClick={async () => handleDeleteButtonOnClick(device.id)}
-              ></Button>
-            </div>
-          ))}
-        </div>
+        </>
       )}
     </div>
   )
diff --git a/packages/web/src/javascripts/Components/Preferences/Panes/Security/U2F/U2FView/U2FTitle.tsx b/packages/web/src/javascripts/Components/Preferences/Panes/Security/U2F/U2FView/U2FTitle.tsx
index 53f286b80..97898cda4 100644
--- a/packages/web/src/javascripts/Components/Preferences/Panes/Security/U2F/U2FView/U2FTitle.tsx
+++ b/packages/web/src/javascripts/Components/Preferences/Panes/Security/U2F/U2FView/U2FTitle.tsx
@@ -10,10 +10,10 @@ type Props = {
 
 const U2FTitle: FunctionComponent<Props> = ({ userProvider }) => {
   if (userProvider.getUser() === undefined) {
-    return <Title>Universal 2nd Factor authentication not available</Title>
+    return <Title>Universal 2nd factor authentication not available</Title>
   }
 
-  return <Title>Universal 2nd Factor authentication</Title>
+  return <Title>Universal 2nd Factor Authentication</Title>
 }
 
 export default observer(U2FTitle)
diff --git a/packages/web/src/javascripts/Components/Preferences/Panes/Security/U2F/U2FView/U2FView.tsx b/packages/web/src/javascripts/Components/Preferences/Panes/Security/U2F/U2FView/U2FView.tsx
index b42b9ca40..41e9b95b0 100644
--- a/packages/web/src/javascripts/Components/Preferences/Panes/Security/U2F/U2FView/U2FView.tsx
+++ b/packages/web/src/javascripts/Components/Preferences/Panes/Security/U2F/U2FView/U2FView.tsx
@@ -11,6 +11,7 @@ import U2FDescription from './U2FDescription'
 import Button from '@/Components/Button/Button'
 import U2FAddDeviceView from '../U2FAddDeviceView'
 import U2FDevicesList from './U2FDevicesList'
+import ModalOverlay from '@/Components/Modal/ModalOverlay'
 
 type Props = {
   application: WebApplication
@@ -45,34 +46,36 @@ const U2FView: FunctionComponent<Props> = ({ application, userProvider }) => {
     <>
       <PreferencesGroup>
         <PreferencesSegment>
-          <div className="flex flex-row items-center">
-            <div className="flex flex-grow flex-col">
-              <U2FTitle userProvider={userProvider} />
-              <U2FDescription userProvider={userProvider} />
-            </div>
-            <PreferencesSegment>
-              <Button label="Add Device" primary onClick={handleAddDeviceClick} />
-            </PreferencesSegment>
+          <div className="flex flex-col">
+            <U2FTitle userProvider={userProvider} />
+            <U2FDescription userProvider={userProvider} />
           </div>
         </PreferencesSegment>
-        <PreferencesSegment>
-          {error && <div className="text-red-500">{error}</div>}
+        <PreferencesSegment classes="mt-2">
+          {error && <div className="text-danger">{error}</div>}
           <U2FDevicesList
             application={application}
             devices={devices}
             onError={setError}
             onDeviceDeleted={loadAuthenticatorDevices}
           />
+          <Button
+            className="mt-1"
+            disabled={!application.isFullU2FClient}
+            label="Add Device"
+            primary
+            onClick={handleAddDeviceClick}
+          />
         </PreferencesSegment>
       </PreferencesGroup>
-      {showDeviceAddingModal && (
+      <ModalOverlay isOpen={showDeviceAddingModal}>
         <U2FAddDeviceView
           onDeviceAddingModalToggle={setShowDeviceAddingModal}
           onDeviceAdded={loadAuthenticatorDevices}
           userProvider={userProvider}
           addAuthenticator={application.addAuthenticator}
         />
-      )}
+      </ModalOverlay>
     </>
   )
 }
diff --git a/packages/web/src/javascripts/Components/U2FAuthIframe/U2FAuthIframe.tsx b/packages/web/src/javascripts/Components/U2FAuthIframe/U2FAuthIframe.tsx
new file mode 100644
index 000000000..990c98aa3
--- /dev/null
+++ b/packages/web/src/javascripts/Components/U2FAuthIframe/U2FAuthIframe.tsx
@@ -0,0 +1,109 @@
+import { useCallback, useEffect, useState } from 'react'
+import Button from '../Button/Button'
+import { startAuthentication } from '@simplewebauthn/browser'
+import { log, LoggingDomain } from '@/Logging'
+
+/**
+ * An iframe for use in the desktop and mobile application that allows them to load app.standardnotes.com to perform
+ * U2F authentication. Web applications do not need this iframe, as they can perform U2F authentication directly.
+ */
+const U2FAuthIframe = () => {
+  const [username, setUsername] = useState('')
+  const [apiHost, setApiHost] = useState<string | null>(null)
+  const [source, setSource] = useState<MessageEvent['source'] | null>(null)
+  const NATIVE_CLIENT_ORIGIN = 'file://'
+
+  useEffect(() => {
+    window.parent.postMessage(
+      {
+        mountedAuthView: true,
+      },
+      NATIVE_CLIENT_ORIGIN,
+    )
+  }, [])
+
+  useEffect(() => {
+    const messageHandler = (event: MessageEvent) => {
+      log(LoggingDomain.U2F, 'U2F iframe received message', event)
+
+      const eventDoesNotComeFromNativeClient = event.origin !== NATIVE_CLIENT_ORIGIN
+      if (eventDoesNotComeFromNativeClient) {
+        log(LoggingDomain.U2F, 'Not setting username; origin does not match', event.origin, NATIVE_CLIENT_ORIGIN)
+        return
+      }
+
+      if (event.data.username) {
+        setUsername(event.data.username)
+        setApiHost(event.data.apiHost)
+        setSource(event.source)
+      }
+    }
+
+    window.addEventListener('message', messageHandler)
+
+    return () => {
+      window.removeEventListener('message', messageHandler)
+    }
+  }, [])
+
+  const [info, setInfo] = useState('')
+  const [error, setError] = useState('')
+
+  const beginAuthentication = useCallback(async () => {
+    setInfo('')
+    setError('')
+
+    try {
+      if (!username || !source) {
+        throw new Error('No username provided')
+      }
+
+      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 || !jsonResponse.data.options) {
+        throw new Error('No options returned from server')
+      }
+
+      setInfo('Waiting for U2F device...')
+
+      const assertionResponse = await startAuthentication(jsonResponse.data.options)
+
+      ;(source as WindowProxy).postMessage(
+        {
+          assertionResponse,
+        },
+        NATIVE_CLIENT_ORIGIN,
+      )
+
+      setInfo('Authentication successful!')
+    } catch (error) {
+      if (!error) {
+        return
+      }
+      setError(error.toString())
+      console.error(error.toString())
+    }
+  }, [source, username, apiHost])
+
+  return (
+    <div className="flex h-full w-full flex-col items-center justify-center gap-2">
+      <div className="mb-2 text-center">Insert your U2F device, then press the button below to authenticate.</div>
+      <Button onClick={beginAuthentication}>Authenticate</Button>
+      <div className="mt-2">
+        <div>{info}</div>
+        <div className="text-danger">{error}</div>
+      </div>
+    </div>
+  )
+}
+
+export default U2FAuthIframe
diff --git a/packages/web/src/javascripts/Logging.ts b/packages/web/src/javascripts/Logging.ts
index fecf2df2c..a50bb6a65 100644
--- a/packages/web/src/javascripts/Logging.ts
+++ b/packages/web/src/javascripts/Logging.ts
@@ -11,6 +11,7 @@ export enum LoggingDomain {
   BlockEditor,
   Purchasing,
   Panes,
+  U2F,
 }
 
 const LoggingStatus: Record<LoggingDomain, boolean> = {
@@ -23,6 +24,7 @@ const LoggingStatus: Record<LoggingDomain, boolean> = {
   [LoggingDomain.BlockEditor]: false,
   [LoggingDomain.Purchasing]: false,
   [LoggingDomain.Panes]: false,
+  [LoggingDomain.U2F]: false,
 }
 
 // eslint-disable-next-line @typescript-eslint/no-explicit-any
diff --git a/yarn.lock b/yarn.lock
index 7c5677ef8..1bd2627a5 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -4622,10 +4622,10 @@ __metadata:
   languageName: node
   linkType: hard
 
-"@simplewebauthn/browser@npm:^7.0.0":
-  version: 7.0.0
-  resolution: "@simplewebauthn/browser@npm:7.0.0"
-  checksum: eb8d7e2d923649c116275cc9bfbabfa27a180cd33dbf9d6a28c7aa9460ea79cd25204c9a7d76ed8cc24764da4a09b5939209aa30e9b295b9d54e497bb9b652a4
+"@simplewebauthn/browser@npm:^7.1.0":
+  version: 7.1.0
+  resolution: "@simplewebauthn/browser@npm:7.1.0"
+  checksum: 925e26607536cd9223e474229df216cc32bc06fac569f27e03c6d31ff502f3dbf6f5a9500caaa37a9abf1632fc99fd582a6596672b7f5468920a74618e1aec6e
   languageName: node
   linkType: hard
 
@@ -5582,7 +5582,7 @@ __metadata:
     "@reach/listbox": ^0.18.0
     "@reach/tooltip": ^0.18.0
     "@reach/visually-hidden": ^0.18.0
-    "@simplewebauthn/browser": ^7.0.0
+    "@simplewebauthn/browser": ^7.1.0
     "@standardnotes/authenticator": ^2.3.9
     "@standardnotes/autobiography-theme": ^1.2.7
     "@standardnotes/bold-editor": ^1.6.4