diff --git a/package.json b/package.json
index 4b42a90..02a0590 100644
--- a/package.json
+++ b/package.json
@@ -38,7 +38,8 @@
     "classnames": "^2.3.1",
     "color-hash": "^2.0.1",
     "events": "^3.3.0",
-    "matrix-js-sdk": "github:matrix-org/matrix-js-sdk#8ba2d257ae24bbed61cd7fe99af081324337161c",
+    "matrix-js-sdk": "github:matrix-org/matrix-js-sdk#3334c01191bcd82b5243916284c9a08d08fd9795",
+    "matrix-widget-api": "^1.0.0",
     "mermaid": "^8.13.8",
     "normalize.css": "^8.0.1",
     "pako": "^2.0.4",
diff --git a/src/ClientContext.tsx b/src/ClientContext.tsx
index a1e5813..08eb91e 100644
--- a/src/ClientContext.tsx
+++ b/src/ClientContext.tsx
@@ -26,9 +26,14 @@ import React, {
 import { useHistory } from "react-router-dom";
 import { MatrixClient, ClientEvent } from "matrix-js-sdk/src/client";
 import { MatrixEvent } from "matrix-js-sdk/src/models/event";
+import { logger } from "matrix-js-sdk/src/logger";
 
 import { ErrorView } from "./FullScreenView";
-import { initClient, defaultHomeserver } from "./matrix-utils";
+import {
+  initClient,
+  initMatroskaClient,
+  defaultHomeserver,
+} from "./matrix-utils";
 
 declare global {
   interface Window {
@@ -91,40 +96,55 @@ export const ClientProvider: FC<Props> = ({ children }) => {
   });
 
   useEffect(() => {
-    const restore = async (): Promise<
+    const init = async (): Promise<
       Pick<ClientProviderState, "client" | "isPasswordlessUser">
     > => {
-      try {
-        const session = loadSession();
+      const query = new URLSearchParams(window.location.search);
+      const widgetId = query.get("widgetId");
+      const parentUrl = query.get("parentUrl");
 
-        if (session) {
-          /* eslint-disable camelcase */
-          const { user_id, device_id, access_token, passwordlessUser } =
-            session;
+      if (widgetId && parentUrl) {
+        // We're inside a widget, so let's engage *Matroska mode*
+        logger.log("Using a Matroska client");
 
-          const client = await initClient(
-            {
-              baseUrl: defaultHomeserver,
-              accessToken: access_token,
-              userId: user_id,
-              deviceId: device_id,
-            },
-            true
-          );
-          /* eslint-enable camelcase */
+        return {
+          client: await initMatroskaClient(widgetId, parentUrl),
+          isPasswordlessUser: false,
+        };
+      } else {
+        // We're running as a standalone application
+        try {
+          const session = loadSession();
 
-          return { client, isPasswordlessUser: passwordlessUser };
+          if (session) {
+            /* eslint-disable camelcase */
+            const { user_id, device_id, access_token, passwordlessUser } =
+              session;
+
+            logger.log("Using a standalone client");
+            const client = await initClient(
+              {
+                baseUrl: defaultHomeserver,
+                accessToken: access_token,
+                userId: user_id,
+                deviceId: device_id,
+              },
+              true
+            );
+            /* eslint-enable camelcase */
+
+            return { client, isPasswordlessUser: passwordlessUser };
+          }
+
+          return { client: undefined, isPasswordlessUser: false };
+        } catch (err) {
+          clearSession();
+          throw err;
         }
-
-        return { client: undefined, isPasswordlessUser: false };
-      } catch (err) {
-        console.error(err);
-        clearSession();
-        throw err;
       }
     };
 
-    restore()
+    init()
       .then(({ client, isPasswordlessUser }) => {
         setState({
           client,
@@ -135,7 +155,8 @@ export const ClientProvider: FC<Props> = ({ children }) => {
           error: undefined,
         });
       })
-      .catch(() => {
+      .catch((err) => {
+        logger.error(err);
         setState({
           client: undefined,
           loading: false,
diff --git a/src/Modal.tsx b/src/Modal.tsx
index f259a18..686234a 100644
--- a/src/Modal.tsx
+++ b/src/Modal.tsx
@@ -37,7 +37,7 @@ import { AriaDialogProps } from "@react-types/dialog";
 import { ReactComponent as CloseIcon } from "./icons/Close.svg";
 import styles from "./Modal.module.css";
 
-interface ModalProps extends OverlayProps, AriaDialogProps {
+export interface ModalProps extends OverlayProps, AriaDialogProps {
   title: string;
   children: ReactNode;
   className?: string;
diff --git a/src/matrix-utils.ts b/src/matrix-utils.ts
index 5986954..ed3cde3 100644
--- a/src/matrix-utils.ts
+++ b/src/matrix-utils.ts
@@ -5,14 +5,21 @@ import { MemoryStore } from "matrix-js-sdk/src/store/memory";
 import { IndexedDBCryptoStore } from "matrix-js-sdk/src/crypto/store/indexeddb-crypto-store";
 import { LocalStorageCryptoStore } from "matrix-js-sdk/src/crypto/store/localStorage-crypto-store";
 import { MemoryCryptoStore } from "matrix-js-sdk/src/crypto/store/memory-crypto-store";
-import { createClient, MatrixClient } from "matrix-js-sdk/src/matrix";
+import {
+  createClient,
+  createRoomWidgetClient,
+  MatrixClient,
+} from "matrix-js-sdk/src/matrix";
 import { ICreateClientOpts } from "matrix-js-sdk/src/matrix";
 import { ClientEvent } from "matrix-js-sdk/src/client";
+import { EventType } from "matrix-js-sdk/src/@types/event";
 import { Visibility, Preset } from "matrix-js-sdk/src/@types/partials";
 import { ISyncStateData, SyncState } from "matrix-js-sdk/src/sync";
+import { WidgetApi } from "matrix-widget-api";
 import { logger } from "matrix-js-sdk/src/logger";
 
 import IndexedDBWorker from "./IndexedDBWorker?worker";
+import { getRoomParams } from "./room/useRoomParams";
 
 export const defaultHomeserver =
   (import.meta.env.VITE_DEFAULT_HOMESERVER as string) ??
@@ -53,7 +60,74 @@ function waitForSync(client: MatrixClient) {
 }
 
 /**
- * Initialises and returns a new Matrix Client
+ * Initialises and returns a new widget-API-based Matrix Client.
+ * @param widgetId The ID of the widget that the app is running inside.
+ * @param parentUrl The URL of the parent client.
+ * @returns The MatrixClient instance
+ */
+export async function initMatroskaClient(
+  widgetId: string,
+  parentUrl: string
+): Promise<MatrixClient> {
+  // In this mode, we use a special client which routes all requests through
+  // the host application via the widget API
+
+  const { roomId, userId, deviceId } = getRoomParams();
+  if (!roomId) throw new Error("Room ID must be supplied");
+  if (!userId) throw new Error("User ID must be supplied");
+  if (!deviceId) throw new Error("Device ID must be supplied");
+
+  // These are all the event types the app uses
+  const sendState = [
+    { eventType: EventType.GroupCallPrefix },
+    { eventType: EventType.GroupCallMemberPrefix, stateKey: userId },
+  ];
+  const receiveState = [
+    { eventType: EventType.RoomMember },
+    { eventType: EventType.GroupCallPrefix },
+    { eventType: EventType.GroupCallMemberPrefix },
+  ];
+  const sendRecvToDevice = [
+    EventType.CallInvite,
+    EventType.CallCandidates,
+    EventType.CallAnswer,
+    EventType.CallHangup,
+    EventType.CallReject,
+    EventType.CallSelectAnswer,
+    EventType.CallNegotiate,
+    EventType.CallSDPStreamMetadataChanged,
+    EventType.CallSDPStreamMetadataChangedPrefix,
+    EventType.CallReplaces,
+    "org.matrix.call_duplicate_session",
+  ];
+
+  // Since all data should be coming from the host application, there's no
+  // need to persist anything, and therefore we can use the default stores
+  // We don't even need to set up crypto
+  const client = createRoomWidgetClient(
+    new WidgetApi(widgetId, new URL(parentUrl).origin),
+    {
+      sendState,
+      receiveState,
+      sendToDevice: sendRecvToDevice,
+      receiveToDevice: sendRecvToDevice,
+      turnServers: true,
+    },
+    roomId,
+    {
+      baseUrl: "",
+      userId,
+      deviceId,
+      timelineSupport: true,
+    }
+  );
+
+  await client.startClient();
+  return client;
+}
+
+/**
+ * Initialises and returns a new standalone Matrix Client.
  * If true is passed for the 'restore' parameter, a check will be made
  * to ensure that corresponding crypto data is stored and recovered.
  * If the check fails, CryptoStoreIntegrityError will be thrown.
@@ -127,16 +201,13 @@ export async function initClient(
     storeOpts.cryptoStore = new MemoryCryptoStore();
   }
 
-  // XXX: we read from the URL search params in RoomPage too:
+  // XXX: we read from the room params in RoomPage too:
   // it would be much better to read them in one place and pass
   // the values around, but we initialise the matrix client in
   // many different places so we'd have to pass it into all of
   // them.
-  const params = new URLSearchParams(window.location.search);
-  // disable e2e only if enableE2e=false is given
-  const enableE2e = params.get("enableE2e") !== "false";
-
-  if (!enableE2e) {
+  const { e2eEnabled } = getRoomParams();
+  if (!e2eEnabled) {
     logger.info("Disabling E2E: group call signalling will NOT be encrypted.");
   }
 
@@ -144,10 +215,10 @@ export async function initClient(
     ...storeOpts,
     ...clientOptions,
     useAuthorizationHeader: true,
-    // Use a relatively low timeout for API calls: this is a realtime application
+    // Use a relatively low timeout for API calls: this is a realtime app
     // so we don't want API calls taking ages, we'd rather they just fail.
     localTimeoutMs: 5000,
-    useE2eForGroupCall: enableE2e,
+    useE2eForGroupCall: e2eEnabled,
   });
 
   try {
@@ -254,17 +325,17 @@ export async function createRoom(
   return [fullAliasFromRoomName(name, client), result.room_id];
 }
 
-export function getRoomUrl(roomId: string): string {
-  if (roomId.startsWith("#")) {
-    const [localPart, host] = roomId.replace("#", "").split(":");
+export function getRoomUrl(roomIdOrAlias: string): string {
+  if (roomIdOrAlias.startsWith("#")) {
+    const [localPart, host] = roomIdOrAlias.replace("#", "").split(":");
 
     if (host !== defaultHomeserverHost) {
-      return `${window.location.protocol}//${window.location.host}/room/${roomId}`;
+      return `${window.location.protocol}//${window.location.host}/room/${roomIdOrAlias}`;
     } else {
       return `${window.location.protocol}//${window.location.host}/${localPart}`;
     }
   } else {
-    return `${window.location.protocol}//${window.location.host}/room/${roomId}`;
+    return `${window.location.protocol}//${window.location.host}/room/#?roomId=${roomIdOrAlias}`;
   }
 }
 
diff --git a/src/room/GroupCallLoader.tsx b/src/room/GroupCallLoader.tsx
index 4cc62f1..dcfbf48 100644
--- a/src/room/GroupCallLoader.tsx
+++ b/src/room/GroupCallLoader.tsx
@@ -23,7 +23,7 @@ import { usePageTitle } from "../usePageTitle";
 
 interface Props {
   client: MatrixClient;
-  roomId: string;
+  roomIdOrAlias: string;
   viaServers: string[];
   children: (groupCall: GroupCall) => ReactNode;
   createPtt: boolean;
@@ -31,14 +31,14 @@ interface Props {
 
 export function GroupCallLoader({
   client,
-  roomId,
+  roomIdOrAlias,
   viaServers,
   children,
   createPtt,
 }: Props): JSX.Element {
   const { loading, error, groupCall } = useLoadGroupCall(
     client,
-    roomId,
+    roomIdOrAlias,
     viaServers,
     createPtt
   );
diff --git a/src/room/GroupCallView.tsx b/src/room/GroupCallView.tsx
index 92e8ef1..2d5ee92 100644
--- a/src/room/GroupCallView.tsx
+++ b/src/room/GroupCallView.tsx
@@ -37,14 +37,14 @@ interface Props {
   client: MatrixClient;
   isPasswordlessUser: boolean;
   isEmbedded: boolean;
-  roomId: string;
+  roomIdOrAlias: string;
   groupCall: GroupCall;
 }
 export function GroupCallView({
   client,
   isPasswordlessUser,
   isEmbedded,
-  roomId,
+  roomIdOrAlias,
   groupCall,
 }: Props) {
   const {
@@ -101,7 +101,7 @@ export function GroupCallView({
       return (
         <PTTCallView
           client={client}
-          roomId={roomId}
+          roomIdOrAlias={roomIdOrAlias}
           roomName={groupCall.room.name}
           avatarUrl={avatarUrl}
           groupCall={groupCall}
@@ -129,7 +129,7 @@ export function GroupCallView({
           isScreensharing={isScreensharing}
           localScreenshareFeed={localScreenshareFeed}
           screenshareFeeds={screenshareFeeds}
-          roomId={roomId}
+          roomIdOrAlias={roomIdOrAlias}
           unencryptedEventsFromUsers={unencryptedEventsFromUsers}
         />
       );
@@ -164,7 +164,7 @@ export function GroupCallView({
           localVideoMuted={localVideoMuted}
           toggleLocalVideoMuted={toggleLocalVideoMuted}
           toggleMicrophoneMuted={toggleMicrophoneMuted}
-          roomId={roomId}
+          roomIdOrAlias={roomIdOrAlias}
           isEmbedded={isEmbedded}
         />
       );
diff --git a/src/room/InCallView.tsx b/src/room/InCallView.tsx
index 680f9f2..5ff3924 100644
--- a/src/room/InCallView.tsx
+++ b/src/room/InCallView.tsx
@@ -71,7 +71,7 @@ interface Props {
   isScreensharing: boolean;
   screenshareFeeds: CallFeed[];
   localScreenshareFeed: CallFeed;
-  roomId: string;
+  roomIdOrAlias: string;
   unencryptedEventsFromUsers: Set<string>;
 }
 
@@ -99,7 +99,7 @@ export function InCallView({
   isScreensharing,
   screenshareFeeds,
   localScreenshareFeed,
-  roomId,
+  roomIdOrAlias,
   unencryptedEventsFromUsers,
 }: Props) {
   usePreventScroll();
@@ -260,7 +260,7 @@ export function InCallView({
         {!fullscreenParticipant && (
           <OverflowMenu
             inCall
-            roomId={roomId}
+            roomIdOrAlias={roomIdOrAlias}
             groupCall={groupCall}
             showInvite={true}
             feedbackModalState={feedbackModalState}
@@ -277,7 +277,7 @@ export function InCallView({
       {rageshakeRequestModalState.isOpen && (
         <RageshakeRequestModal
           {...rageshakeRequestModalProps}
-          roomId={roomId}
+          roomIdOrAlias={roomIdOrAlias}
         />
       )}
     </div>
diff --git a/src/room/InviteModal.tsx b/src/room/InviteModal.tsx
index b9c28c5..7c0e759 100644
--- a/src/room/InviteModal.tsx
+++ b/src/room/InviteModal.tsx
@@ -14,31 +14,30 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
-import React from "react";
+import React, { FC } from "react";
 
-import { Modal, ModalContent } from "../Modal";
+import { Modal, ModalContent, ModalProps } from "../Modal";
 import { CopyButton } from "../button";
 import { getRoomUrl } from "../matrix-utils";
 import styles from "./InviteModal.module.css";
 
-export function InviteModal({
-  roomId,
-  ...rest
-}: {
-  roomId: string;
-  [x: string]: unknown;
-}) {
-  return (
-    <Modal
-      title="Invite People"
-      isDismissable
-      className={styles.inviteModal}
-      {...rest}
-    >
-      <ModalContent>
-        <p>Copy and share this meeting link</p>
-        <CopyButton className={styles.copyButton} value={getRoomUrl(roomId)} />
-      </ModalContent>
-    </Modal>
-  );
+interface Props extends Omit<ModalProps, "title" | "children"> {
+  roomIdOrAlias: string;
 }
+
+export const InviteModal: FC<Props> = ({ roomIdOrAlias, ...rest }) => (
+  <Modal
+    title="Invite People"
+    isDismissable
+    className={styles.inviteModal}
+    {...rest}
+  >
+    <ModalContent>
+      <p>Copy and share this meeting link</p>
+      <CopyButton
+        className={styles.copyButton}
+        value={getRoomUrl(roomIdOrAlias)}
+      />
+    </ModalContent>
+  </Modal>
+);
diff --git a/src/room/LobbyView.tsx b/src/room/LobbyView.tsx
index 9b9be3d..9075aac 100644
--- a/src/room/LobbyView.tsx
+++ b/src/room/LobbyView.tsx
@@ -45,7 +45,7 @@ interface Props {
   toggleLocalVideoMuted: () => void;
   toggleMicrophoneMuted: () => void;
   localVideoMuted: boolean;
-  roomId: string;
+  roomIdOrAlias: string;
   isEmbedded: boolean;
 }
 export function LobbyView({
@@ -61,7 +61,7 @@ export function LobbyView({
   localVideoMuted,
   toggleLocalVideoMuted,
   toggleMicrophoneMuted,
-  roomId,
+  roomIdOrAlias,
   isEmbedded,
 }: Props) {
   const { stream } = useCallFeed(localCallFeed);
@@ -115,7 +115,7 @@ export function LobbyView({
             <VideoPreview
               state={state}
               client={client}
-              roomId={roomId}
+              roomIdOrAlias={roomIdOrAlias}
               microphoneMuted={microphoneMuted}
               localVideoMuted={localVideoMuted}
               toggleLocalVideoMuted={toggleLocalVideoMuted}
@@ -136,7 +136,7 @@ export function LobbyView({
           <Body>Or</Body>
           <CopyButton
             variant="secondaryCopy"
-            value={getRoomUrl(roomId)}
+            value={getRoomUrl(roomIdOrAlias)}
             className={styles.copyButton}
             copiedMessage="Call link copied"
           >
diff --git a/src/room/OverflowMenu.tsx b/src/room/OverflowMenu.tsx
index e58f8f0..f973f8b 100644
--- a/src/room/OverflowMenu.tsx
+++ b/src/room/OverflowMenu.tsx
@@ -32,7 +32,7 @@ import { InviteModal } from "./InviteModal";
 import { TooltipTrigger } from "../Tooltip";
 import { FeedbackModal } from "./FeedbackModal";
 interface Props {
-  roomId: string;
+  roomIdOrAlias: string;
   inCall: boolean;
   groupCall: GroupCall;
   showInvite: boolean;
@@ -43,7 +43,7 @@ interface Props {
   };
 }
 export function OverflowMenu({
-  roomId,
+  roomIdOrAlias,
   inCall,
   groupCall,
   showInvite,
@@ -119,7 +119,7 @@ export function OverflowMenu({
       </PopoverMenuTrigger>
       {settingsModalState.isOpen && <SettingsModal {...settingsModalProps} />}
       {inviteModalState.isOpen && (
-        <InviteModal roomId={roomId} {...inviteModalProps} />
+        <InviteModal roomIdOrAlias={roomIdOrAlias} {...inviteModalProps} />
       )}
       {feedbackModalState.isOpen && (
         <FeedbackModal
diff --git a/src/room/PTTCallView.tsx b/src/room/PTTCallView.tsx
index 9f56b0d..dbdf90d 100644
--- a/src/room/PTTCallView.tsx
+++ b/src/room/PTTCallView.tsx
@@ -87,7 +87,7 @@ function getPromptText(
 
 interface Props {
   client: MatrixClient;
-  roomId: string;
+  roomIdOrAlias: string;
   roomName: string;
   avatarUrl: string;
   groupCall: GroupCall;
@@ -99,7 +99,7 @@ interface Props {
 
 export const PTTCallView: React.FC<Props> = ({
   client,
-  roomId,
+  roomIdOrAlias,
   roomName,
   avatarUrl,
   groupCall,
@@ -205,7 +205,7 @@ export const PTTCallView: React.FC<Props> = ({
             <div className={styles.footer}>
               <OverflowMenu
                 inCall
-                roomId={roomId}
+                roomIdOrAlias={roomIdOrAlias}
                 groupCall={groupCall}
                 showInvite={false}
                 feedbackModalState={feedbackModalState}
@@ -282,7 +282,7 @@ export const PTTCallView: React.FC<Props> = ({
       </div>
 
       {inviteModalState.isOpen && showControls && (
-        <InviteModal roomId={roomId} {...inviteModalProps} />
+        <InviteModal roomIdOrAlias={roomIdOrAlias} {...inviteModalProps} />
       )}
     </div>
   );
diff --git a/src/room/RageshakeRequestModal.tsx b/src/room/RageshakeRequestModal.tsx
index 3313bd1..59b74b3 100644
--- a/src/room/RageshakeRequestModal.tsx
+++ b/src/room/RageshakeRequestModal.tsx
@@ -14,24 +14,25 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
-import React, { useEffect } from "react";
+import React, { FC, useEffect } from "react";
 
-import { Modal, ModalContent } from "../Modal";
+import { Modal, ModalContent, ModalProps } from "../Modal";
 import { Button } from "../button";
 import { FieldRow, ErrorMessage } from "../input/Input";
 import { useSubmitRageshake } from "../settings/submit-rageshake";
 import { Body } from "../typography/Typography";
 
-export function RageshakeRequestModal({
-  rageshakeRequestId,
-  roomId,
-  ...rest
-}: {
+interface Props extends Omit<ModalProps, "title" | "children"> {
   rageshakeRequestId: string;
-  roomId: string;
+  roomIdOrAlias: string;
   onClose: () => void;
-  [x: string]: unknown;
-}) {
+}
+
+export const RageshakeRequestModal: FC<Props> = ({
+  rageshakeRequestId,
+  roomIdOrAlias,
+  ...rest
+}) => {
   const { submitRageshake, sending, sent, error } = useSubmitRageshake();
 
   useEffect(() => {
@@ -53,7 +54,7 @@ export function RageshakeRequestModal({
               submitRageshake({
                 sendLogs: true,
                 rageshakeRequestId,
-                roomId,
+                roomId: roomIdOrAlias, // Possibly not a room ID, but oh well
               })
             }
             disabled={sending}
@@ -69,4 +70,4 @@ export function RageshakeRequestModal({
       </ModalContent>
     </Modal>
   );
-}
+};
diff --git a/src/room/RoomPage.tsx b/src/room/RoomPage.tsx
index fa9f9c0..c41ac6a 100644
--- a/src/room/RoomPage.tsx
+++ b/src/room/RoomPage.tsx
@@ -1,5 +1,5 @@
 /*
-Copyright 2021 New Vector Ltd
+Copyright 2021-2022 New Vector Ltd
 
 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.
@@ -14,33 +14,26 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
-import React, { useEffect, useMemo, useState } from "react";
-import { useLocation, useParams } from "react-router-dom";
+import React, { FC, useEffect, useState } from "react";
 
 import { useClient } from "../ClientContext";
 import { ErrorView, LoadingView } from "../FullScreenView";
 import { RoomAuthView } from "./RoomAuthView";
 import { GroupCallLoader } from "./GroupCallLoader";
 import { GroupCallView } from "./GroupCallView";
+import { useRoomParams } from "./useRoomParams";
 import { MediaHandlerProvider } from "../settings/useMediaHandler";
 import { useRegisterPasswordlessUser } from "../auth/useRegisterPasswordlessUser";
 
-export function RoomPage() {
+export const RoomPage: FC = () => {
   const { loading, isAuthenticated, error, client, isPasswordlessUser } =
     useClient();
 
-  const { roomId: maybeRoomId } = useParams();
-  const { hash, search }: { hash: string; search: string } = useLocation();
-  const [viaServers, isEmbedded, isPtt, displayName] = useMemo(() => {
-    const params = new URLSearchParams(search);
-    return [
-      params.getAll("via"),
-      params.has("embed"),
-      params.get("ptt") === "true",
-      params.get("displayName"),
-    ];
-  }, [search]);
-  const roomId = (maybeRoomId || hash || "").toLowerCase();
+  const { roomAlias, roomId, viaServers, isEmbedded, isPtt, displayName } =
+    useRoomParams();
+  const roomIdOrAlias = roomId ?? roomAlias;
+  if (!roomIdOrAlias) throw new Error("No room specified");
+
   const { registerPasswordlessUser } = useRegisterPasswordlessUser();
   const [isRegistering, setIsRegistering] = useState(false);
 
@@ -76,14 +69,14 @@ export function RoomPage() {
     <MediaHandlerProvider client={client}>
       <GroupCallLoader
         client={client}
-        roomId={roomId}
+        roomIdOrAlias={roomIdOrAlias}
         viaServers={viaServers}
         createPtt={isPtt}
       >
         {(groupCall) => (
           <GroupCallView
             client={client}
-            roomId={roomId}
+            roomIdOrAlias={roomIdOrAlias}
             groupCall={groupCall}
             isPasswordlessUser={isPasswordlessUser}
             isEmbedded={isEmbedded}
@@ -92,4 +85,4 @@ export function RoomPage() {
       </GroupCallLoader>
     </MediaHandlerProvider>
   );
-}
+};
diff --git a/src/room/VideoPreview.tsx b/src/room/VideoPreview.tsx
index 58f2c92..21b559d 100644
--- a/src/room/VideoPreview.tsx
+++ b/src/room/VideoPreview.tsx
@@ -32,7 +32,7 @@ import { useModalTriggerState } from "../Modal";
 interface Props {
   client: MatrixClient;
   state: GroupCallState;
-  roomId: string;
+  roomIdOrAlias: string;
   microphoneMuted: boolean;
   localVideoMuted: boolean;
   toggleLocalVideoMuted: () => void;
@@ -43,7 +43,7 @@ interface Props {
 export function VideoPreview({
   client,
   state,
-  roomId,
+  roomIdOrAlias,
   microphoneMuted,
   localVideoMuted,
   toggleLocalVideoMuted,
@@ -93,7 +93,7 @@ export function VideoPreview({
               onPress={toggleLocalVideoMuted}
             />
             <OverflowMenu
-              roomId={roomId}
+              roomIdOrAlias={roomIdOrAlias}
               feedbackModalState={feedbackModalState}
               feedbackModalProps={feedbackModalProps}
               inCall={false}
diff --git a/src/room/useRoomParams.ts b/src/room/useRoomParams.ts
new file mode 100644
index 0000000..070137d
--- /dev/null
+++ b/src/room/useRoomParams.ts
@@ -0,0 +1,93 @@
+/*
+Copyright 2022 New Vector Ltd
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+ */
+
+import { useMemo } from "react";
+import { useLocation } from "react-router-dom";
+
+export interface RoomParams {
+  roomAlias: string | null;
+  roomId: string | null;
+  viaServers: string[];
+  // Whether the app is running in embedded mode, and should keep the user
+  // confined to the current room
+  isEmbedded: boolean;
+  // Whether to start a walkie-talkie call instead of a video call
+  isPtt: boolean;
+  // Whether to use end-to-end encryption
+  e2eEnabled: boolean;
+  // The user's ID (only used in Matroska mode)
+  userId: string | null;
+  // The display name to use for auto-registration
+  displayName: string | null;
+  // The device's ID (only used in Matroska mode)
+  deviceId: string | null;
+}
+
+/**
+ * Gets the room parameters for the current URL.
+ * @param {string} query The URL query string
+ * @param {string} fragment The URL fragment string
+ * @returns {RoomParams} The room parameters encoded in the URL
+ */
+export const getRoomParams = (
+  query: string = window.location.search,
+  fragment: string = window.location.hash
+): RoomParams => {
+  const fragmentQueryStart = fragment.indexOf("?");
+  const fragmentParams = new URLSearchParams(
+    fragmentQueryStart === -1 ? "" : fragment.substring(fragmentQueryStart)
+  );
+  const queryParams = new URLSearchParams(query);
+
+  // Normally, room params should be encoded in the fragment so as to avoid
+  // leaking them to the server. However, we also check the normal query
+  // string for backwards compatibility with versions that only used that.
+  const hasParam = (name: string): boolean =>
+    fragmentParams.has(name) || queryParams.has(name);
+  const getParam = (name: string): string | null =>
+    fragmentParams.get(name) ?? queryParams.get(name);
+  const getAllParams = (name: string): string[] => [
+    ...fragmentParams.getAll(name),
+    ...queryParams.getAll(name),
+  ];
+
+  // The part of the fragment before the ?
+  const fragmentRoute =
+    fragmentQueryStart === -1
+      ? fragment
+      : fragment.substring(0, fragmentQueryStart);
+
+  return {
+    roomAlias: fragmentRoute.length > 1 ? fragmentRoute : null,
+    roomId: getParam("roomId"),
+    viaServers: getAllParams("via"),
+    isEmbedded: hasParam("embed"),
+    isPtt: hasParam("ptt"),
+    e2eEnabled: getParam("enableE2e") !== "false", // Defaults to true
+    userId: getParam("userId"),
+    displayName: getParam("displayName"),
+    deviceId: getParam("deviceId"),
+  };
+};
+
+/**
+ * Hook to simplify use of getRoomParams.
+ * @returns {RoomParams} The room parameters for the current URL
+ */
+export const useRoomParams = (): RoomParams => {
+  const { hash, search } = useLocation();
+  return useMemo(() => getRoomParams(search, hash), [search, hash]);
+};
diff --git a/vite.config.js b/vite.config.js
index 95f6c3d..83440ca 100644
--- a/vite.config.js
+++ b/vite.config.js
@@ -41,6 +41,12 @@ export default defineConfig(({ mode }) => {
       },
     },
     resolve: {
+      alias: {
+        // matrix-widget-api has its transpiled lib/index.js as its entry point,
+        // which Vite for some reason refuses to work with, so we point it to
+        // src/index.ts instead
+        "matrix-widget-api": "matrix-widget-api/src/index.ts",
+      },
       dedupe: [
         "react",
         "react-dom",
diff --git a/yarn.lock b/yarn.lock
index cb70c7d..26dcd48 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -2754,6 +2754,11 @@
   resolved "https://registry.yarnpkg.com/@types/estree/-/estree-0.0.51.tgz#cfd70924a25a3fd32b218e5e420e6897e1ac4f40"
   integrity sha512-CuPgU6f3eT/XgKKPqKd/gLZV1Xmvf1a2R5POBOGQa6uv82xpls89HU5zKeVoyR8XzHd1RGNOlQlvUe3CFkjWNQ==
 
+"@types/events@^3.0.0":
+  version "3.0.0"
+  resolved "https://registry.yarnpkg.com/@types/events/-/events-3.0.0.tgz#2862f3f58a9a7f7c3e78d79f130dd4d71c25c2a7"
+  integrity sha512-EaObqwIvayI5a8dCzhFrjKzVwKLxjoG9T6Ppd5CEo07LRKfQ8Yokw54r5+Wq7FaBQ+yXRvQAYPrHwya1/UFt9g==
+
 "@types/glob@*", "@types/glob@^7.1.1", "@types/glob@^7.1.3":
   version "7.2.0"
   resolved "https://registry.yarnpkg.com/@types/glob/-/glob-7.2.0.tgz#bc1b5bf3aa92f25bd5dd39f35c57361bdce5b2eb"
@@ -3863,12 +3868,10 @@ balanced-match@^1.0.0:
   resolved "https://registry.yarnpkg.com/balanced-match/-/balanced-match-1.0.2.tgz#e83e3a7e3f300b34cb9d87f615fa0cbf357690ee"
   integrity sha512-3oSeUO0TMV67hN1AmbXsK4yaqU7tjiHlbxRDZOpH0KW9+CeX4bRAaX0Anxt0tx2MrpRpWwQaPwIlISEJhYU5Pw==
 
-base-x@^3.0.2:
-  version "3.0.9"
-  resolved "https://registry.yarnpkg.com/base-x/-/base-x-3.0.9.tgz#6349aaabb58526332de9f60995e548a53fe21320"
-  integrity sha512-H7JU6iBHTal1gp56aKoaa//YUxEaAOUiydvrV/pILqIHXTtqxSkATOnDA2u+jZ/61sD+L/412+7kzXRtWukhpQ==
-  dependencies:
-    safe-buffer "^5.0.1"
+base-x@^4.0.0:
+  version "4.0.0"
+  resolved "https://registry.yarnpkg.com/base-x/-/base-x-4.0.0.tgz#d0e3b7753450c73f8ad2389b5c018a4af7b2224a"
+  integrity sha512-FuwxlW4H5kh37X/oW59pwTzzTKRzfrrQwhmyspRM7swOEZcHtDZSCt45U6oKgtuFE+WYPblePMVIPR4RZrh/hw==
 
 base16@^1.0.0:
   version "1.0.0"
@@ -4105,12 +4108,12 @@ browserslist@^4.12.0, browserslist@^4.14.5, browserslist@^4.20.2, browserslist@^
     node-releases "^2.0.5"
     update-browserslist-db "^1.0.4"
 
-bs58@^4.0.1:
-  version "4.0.1"
-  resolved "https://registry.yarnpkg.com/bs58/-/bs58-4.0.1.tgz#be161e76c354f6f788ae4071f63f34e8c4f0a42a"
-  integrity sha512-Ok3Wdf5vOIlBrgCvTq96gBkJw+JUEzdBgyaza5HLtPm7yTHkjRy8+JzNyHF7BHa0bNWOQIp3m5YF0nnFcOIKLw==
+bs58@^5.0.0:
+  version "5.0.0"
+  resolved "https://registry.yarnpkg.com/bs58/-/bs58-5.0.0.tgz#865575b4d13c09ea2a84622df6c8cbeb54ffc279"
+  integrity sha512-r+ihvQJvahgYT50JD05dyJNKlmmSlMoOGwn1lCcEzanPglg7TxYjioQUYehQ9mAR/+hOSd2jRc/Z2y5UxBymvQ==
   dependencies:
-    base-x "^3.0.2"
+    base-x "^4.0.0"
 
 buffer-from@^1.0.0:
   version "1.1.2"
@@ -8387,24 +8390,33 @@ matrix-events-sdk@^0.0.1-beta.7:
   resolved "https://registry.yarnpkg.com/matrix-events-sdk/-/matrix-events-sdk-0.0.1-beta.7.tgz#5ffe45eba1f67cc8d7c2377736c728b322524934"
   integrity sha512-9jl4wtWanUFSy2sr2lCjErN/oC8KTAtaeaozJtrgot1JiQcEI4Rda9OLgQ7nLKaqb4Z/QUx/fR3XpDzm5Jy1JA==
 
-"matrix-js-sdk@github:matrix-org/matrix-js-sdk#8ba2d257ae24bbed61cd7fe99af081324337161c":
-  version "19.0.0"
-  resolved "https://codeload.github.com/matrix-org/matrix-js-sdk/tar.gz/8ba2d257ae24bbed61cd7fe99af081324337161c"
+"matrix-js-sdk@github:matrix-org/matrix-js-sdk#3334c01191bcd82b5243916284c9a08d08fd9795":
+  version "19.2.0"
+  resolved "https://codeload.github.com/matrix-org/matrix-js-sdk/tar.gz/3334c01191bcd82b5243916284c9a08d08fd9795"
   dependencies:
     "@babel/runtime" "^7.12.5"
     "@types/sdp-transform" "^2.4.5"
     another-json "^0.2.0"
     browser-request "^0.3.3"
-    bs58 "^4.0.1"
+    bs58 "^5.0.0"
     content-type "^1.0.4"
     loglevel "^1.7.1"
     matrix-events-sdk "^0.0.1-beta.7"
-    p-retry "^4.5.0"
+    matrix-widget-api "^1.0.0"
+    p-retry "4"
     qs "^6.9.6"
     request "^2.88.2"
     sdp-transform "^2.14.1"
     unhomoglyph "^1.0.6"
 
+matrix-widget-api@^1.0.0:
+  version "1.0.0"
+  resolved "https://registry.yarnpkg.com/matrix-widget-api/-/matrix-widget-api-1.0.0.tgz#0cde6839cca66ad817ab12aca3490ccc8bac97d1"
+  integrity sha512-cy8p/8EteRPTFIAw7Q9EgPUJc2jD19ZahMR8bMKf2NkILDcjuPMC0UWnsJyB3fSnlGw+VbGepttRpULM31zX8Q==
+  dependencies:
+    "@types/events" "^3.0.0"
+    events "^3.2.0"
+
 md5.js@^1.3.4:
   version "1.3.5"
   resolved "https://registry.yarnpkg.com/md5.js/-/md5.js-1.3.5.tgz#b5d07b8e3216e3e27cd728d72f70d1e6a342005f"
@@ -9189,7 +9201,7 @@ p-map@^4.0.0:
   dependencies:
     aggregate-error "^3.0.0"
 
-p-retry@^4.5.0:
+p-retry@4:
   version "4.6.2"
   resolved "https://registry.yarnpkg.com/p-retry/-/p-retry-4.6.2.tgz#9baae7184057edd4e17231cee04264106e092a16"
   integrity sha512-312Id396EbJdvRONlngUx0NydfrIQ5lsYu0znKVUzVvArzEIt08V1qhtyESbGVd1FGX7UKtiFp5uwKZdM8wIuQ==