diff --git a/src/app/components/create-room/utils.ts b/src/app/components/create-room/utils.ts
index 05ad79c33..4a00e54fa 100644
--- a/src/app/components/create-room/utils.ts
+++ b/src/app/components/create-room/utils.ts
@@ -80,7 +80,7 @@ const createSpacePowerLevelsOverride = () => ({
 });
 
 export const createRoomEncryptionState = () => ({
-  type: 'm.room.encryption',
+  type: EventType.RoomEncryption,
   state_key: '',
   content: {
     algorithm: 'm.megolm.v1.aes-sha2',
diff --git a/src/app/components/event-history/EventHistory.tsx b/src/app/components/event-history/EventHistory.tsx
index 7fc644262..810cbd9b0 100644
--- a/src/app/components/event-history/EventHistory.tsx
+++ b/src/app/components/event-history/EventHistory.tsx
@@ -48,7 +48,7 @@ import { usePowerLevelsContext } from '$hooks/usePowerLevels';
 
 import { useSettingsLinkBaseUrl } from '$features/settings/useSettingsLinkBaseUrl';
 import * as css from './EventHistory.css';
-import { EventType } from '$types/matrix-sdk';
+import { EventType, RelationType } from '$types/matrix-sdk';
 
 type EventHistoryProps = {
   room: Room;
@@ -104,7 +104,7 @@ export const EventHistory = as<'div', EventHistoryProps>(
         const formattedBody =
           content?.['m.new_content']?.formatted_body ?? content?.formatted_body ?? '';
         const { 'm.relates_to': relation } = startThread
-          ? { 'm.relates_to': { rel_type: 'm.thread', event_id: replyId } }
+          ? { 'm.relates_to': { rel_type: RelationType.Thread, event_id: replyId } }
           : replyEvt.getWireContent();
         const senderId = replyEvt.getSender();
         if (senderId) {
diff --git a/src/app/components/message/PollEvent.tsx b/src/app/components/message/PollEvent.tsx
index 7060af819..dd29bf969 100644
--- a/src/app/components/message/PollEvent.tsx
+++ b/src/app/components/message/PollEvent.tsx
@@ -13,6 +13,7 @@ import {
 } from 'matrix-js-sdk';
 import * as css from './PollEvent.css';
 import { useCallback, useEffect, useState } from 'react';
+import { MsgType, RelationType } from '$types/matrix-sdk';
 import { PollResponsesViewer } from '$features/room/poll-modals';
 import { ModalOverlay } from '$components/modal-overlay/ModalOverlay';
 import { useMatrixEvent } from '$hooks/useMatrixEvent';
@@ -188,7 +189,7 @@ export function PollEvent({ content, mEvent, mx, room }: PollEventProps) {
 
     let newContent: PollResponse = {
       'm.relates_to': {
-        rel_type: 'm.reference',
+        rel_type: RelationType.Reference,
         event_id: eventId,
       },
       [M_POLL_RESPONSE.name]: {
@@ -220,13 +221,13 @@ export function PollEvent({ content, mEvent, mx, room }: PollEventProps) {
 
     const endContent = {
       'm.relates_to': {
-        rel_type: 'm.reference',
+        rel_type: RelationType.Reference,
         event_id: eventId,
       },
       'org.matrix.msc3381.poll.end': {},
       [M_TEXT.name]: endText,
       body: endText,
-      msgtype: 'm.text',
+      msgtype: MsgType.Text,
     };
     mx.sendEvent(
       roomId,
diff --git a/src/app/components/message/modals/MessageForward.tsx b/src/app/components/message/modals/MessageForward.tsx
index 9752dec20..01a651995 100644
--- a/src/app/components/message/modals/MessageForward.tsx
+++ b/src/app/components/message/modals/MessageForward.tsx
@@ -6,6 +6,7 @@ import { MenuItem, Text, as } from 'folds';
 import { ArrowRight, menuIcon } from '$components/icons/phosphor';
 import { useSetAtom } from 'jotai';
 import type { MatrixEvent, Room } from '$types/matrix-sdk';
+import { MsgType } from '$types/matrix-sdk';
 import { useCallback, useEffect, useMemo, useState } from 'react';
 import { useAllJoinedRoomsSet, useGetRoom } from '$hooks/useGetRoom';
 import { useMessageTargetRooms } from '$hooks/useMessageTargetRooms';
@@ -129,7 +130,7 @@ export function MessageForwardInternal({
 
       const eventType = mEvent.getType() as SendEventType;
       const originalContent = mEvent.getContent();
-      const isTextMessage = originalContent.msgtype === 'm.text';
+      const isTextMessage = originalContent.msgtype === MsgType.Text;
 
       const originalBody = typeof originalContent.body === 'string' ? originalContent.body : '';
       const originalFormattedBody =
diff --git a/src/app/components/message/modals/Options.tsx b/src/app/components/message/modals/Options.tsx
index 7ad25366b..0f5b27dee 100644
--- a/src/app/components/message/modals/Options.tsx
+++ b/src/app/components/message/modals/Options.tsx
@@ -586,7 +586,7 @@ function OptionMenu({
   const store = useStore();
   const mx = useMatrixClient();
   const isThreadedMessage = isThreadRelationEvent(mEvent, mEvent.threadRootId);
-  const isStickerMessage = mEvent.getType() === 'm.stidoecker';
+  const isStickerMessage = mEvent.getType() === (EventType.Sticker as string);
   const evtId = mEvent.getId()!;
   const evtTimeline = room.getTimelineForEvent(evtId);
   const edits =
diff --git a/src/app/features/common-settings/developer-tools/DevelopTools.tsx b/src/app/features/common-settings/developer-tools/DevelopTools.tsx
index cdbf5d19a..52ae323f7 100644
--- a/src/app/features/common-settings/developer-tools/DevelopTools.tsx
+++ b/src/app/features/common-settings/developer-tools/DevelopTools.tsx
@@ -102,7 +102,11 @@ export function DeveloperTools({ requestBack, requestClose }: DeveloperToolsProp
     const latestTimelineEventId = latestTimelineEvent?.getId() ?? null;
     const latestMessageEvent = [...liveEvents].toReversed().find((event) => {
       const type = event.getType();
-      return type === 'm.room.message' || type === 'm.room.encrypted' || type === 'm.sticker';
+      return (
+        type === (EventType.RoomMessage as string) ||
+        type === (EventType.RoomMessageEncrypted as string) ||
+        type === (EventType.Sticker as string)
+      );
     });
     const latestMessageEventId = latestMessageEvent?.getId() ?? null;
     const latestNotificationEvent = [...liveEvents]
diff --git a/src/app/features/room/RoomTimeline.tsx b/src/app/features/room/RoomTimeline.tsx
index e8f858e25..327e51505 100644
--- a/src/app/features/room/RoomTimeline.tsx
+++ b/src/app/features/room/RoomTimeline.tsx
@@ -1169,7 +1169,7 @@ export function RoomTimeline({
         .find(
           (e) =>
             e.mEvent.getSender() === myUserId &&
-            e.mEvent.getType() === 'm.room.message' &&
+            e.mEvent.getType() === (EventType.RoomMessage as string) &&
             !e.mEvent.isRedacted()
         );
       if (found?.mEvent.getId()) actions.handleEdit(found.mEvent.getId());
diff --git a/src/app/features/room/location-modal/LocationDialog.tsx b/src/app/features/room/location-modal/LocationDialog.tsx
index 6a14deac7..d35c07281 100644
--- a/src/app/features/room/location-modal/LocationDialog.tsx
+++ b/src/app/features/room/location-modal/LocationDialog.tsx
@@ -12,6 +12,7 @@ import type { LatLngLiteral } from 'leaflet';
 import L from 'leaflet';
 import { getReplyContent } from '../RoomInput';
 import type { RoomMessageEventContent } from '$types/matrix-sdk';
+import { MsgType } from '$types/matrix-sdk';
 import { settingsAtom } from '$state/settings';
 import { useSetting } from '$state/hooks/settings';
 import classNames from 'classnames';
@@ -238,7 +239,7 @@ export function LocationDialog({
     const mlat = pinPosition.lat.toFixed(6);
     const mlon = pinPosition.lng.toFixed(6);
     const content: IContent = {
-      msgtype: 'm.location',
+      msgtype: MsgType.Location,
       geo_uri: `geo:${mlat},${mlon};u=0`,
       body: `https://www.openstreetmap.org/?mlat=${mlat}&mlon=${mlon}#map=16/${mlat}/${mlon}"`,
     };
diff --git a/src/app/features/room/message/Message.tsx b/src/app/features/room/message/Message.tsx
index 01636c402..6926a8d6b 100644
--- a/src/app/features/room/message/Message.tsx
+++ b/src/app/features/room/message/Message.tsx
@@ -24,7 +24,7 @@ import {
 } from 'react';
 import { useHover, useFocusWithin } from 'react-aria';
 import type { MatrixEvent, Room, Relations } from '$types/matrix-sdk';
-import { EventStatus, MatrixEventEvent, RoomEvent } from '$types/matrix-sdk';
+import { EventStatus, MatrixEventEvent, MsgType, RoomEvent } from '$types/matrix-sdk';
 import classNames from 'classnames';
 import { useSetAtom } from 'jotai';
 import {
@@ -393,7 +393,7 @@ function MessageInternal(
 
   const isGif = useMemo(() => {
     const content = mEvent.getContent();
-    if (content.msgtype !== 'm.image') return false;
+    if (content.msgtype !== MsgType.Image) return false;
     return checkIfGif(content?.info?.url ?? '', content?.info?.mimetype, content?.body);
   }, [mEvent]);
 
diff --git a/src/app/features/room/poll-modals/PollDialog.tsx b/src/app/features/room/poll-modals/PollDialog.tsx
index a906bfc4a..a0e15b8f6 100644
--- a/src/app/features/room/poll-modals/PollDialog.tsx
+++ b/src/app/features/room/poll-modals/PollDialog.tsx
@@ -25,6 +25,7 @@ import {
   M_POLL_START,
   M_TEXT,
 } from 'matrix-js-sdk';
+import { MsgType } from '$types/matrix-sdk';
 import { isKeyHotkey } from 'is-hotkey';
 import * as css from './PollDialog.css';
 import type { IReplyDraft } from '$state/room/roomInputDrafts';
@@ -113,7 +114,7 @@ export function PollDialog({ onCancel, mx, room, replyDraft, clearReplyDraft }:
         question: {
           [M_TEXT.name]: title.current,
           body: title.current,
-          msgtype: 'm.text',
+          msgtype: MsgType.Text,
         },
         kind: isDisclosed ? M_POLL_KIND_DISCLOSED.name : M_POLL_KIND_UNDISCLOSED.name,
         max_selections: maxSelections,
diff --git a/src/app/features/room/schedule-send/ScheduledMessagesList.tsx b/src/app/features/room/schedule-send/ScheduledMessagesList.tsx
index 5ddc1bf8e..16583b392 100644
--- a/src/app/features/room/schedule-send/ScheduledMessagesList.tsx
+++ b/src/app/features/room/schedule-send/ScheduledMessagesList.tsx
@@ -11,7 +11,7 @@ import {
   X,
 } from '$components/icons/phosphor';
 import type { Room } from '$types/matrix-sdk';
-import { MatrixEvent } from '$types/matrix-sdk';
+import { EventType, MatrixEvent } from '$types/matrix-sdk';
 import { useAtom, useAtomValue, useSetAtom } from 'jotai';
 import { useMatrixClient } from '$hooks/useMatrixClient';
 import {
@@ -157,7 +157,8 @@ export function ScheduledMessagesList({ room, onEditMessage }: ScheduledMessages
   const roomEvents = data?.delayed_events.filter(
     (event) =>
       event.room_id === room.roomId &&
-      (event.type === 'm.room.message' || event.type === 'm.room.encrypted')
+      (event.type === (EventType.RoomMessage as string) ||
+        event.type === (EventType.RoomMessageEncrypted as string))
   );
 
   const invalidateEvents = useCallback(() => {
diff --git a/src/app/features/settings/notifications/AllMessages.tsx b/src/app/features/settings/notifications/AllMessages.tsx
index 87d5a699e..66d4d4895 100644
--- a/src/app/features/settings/notifications/AllMessages.tsx
+++ b/src/app/features/settings/notifications/AllMessages.tsx
@@ -25,7 +25,7 @@ const getAllMessageDefaultRule = (
   conditions.push({
     kind: ConditionKind.EventMatch,
     key: 'type',
-    pattern: encrypted ? 'm.room.encrypted' : 'm.room.message',
+    pattern: encrypted ? EventType.RoomMessageEncrypted : EventType.RoomMessage,
   });
 
   return {
diff --git a/src/app/features/settings/notifications/UnifiedPushNotifications.ts b/src/app/features/settings/notifications/UnifiedPushNotifications.ts
index 3375271e6..31ed4dda7 100644
--- a/src/app/features/settings/notifications/UnifiedPushNotifications.ts
+++ b/src/app/features/settings/notifications/UnifiedPushNotifications.ts
@@ -364,7 +364,7 @@ async function decryptPreviewFromPayload(
   const crypto = mx.getCrypto();
   if (!crypto || !pushData.content) return undefined;
   const mEvent = new MatrixEvent({
-    type: 'm.room.encrypted',
+    type: EventType.RoomMessageEncrypted,
     content: pushData.content,
     room_id: roomId,
     event_id: eventId,
diff --git a/src/app/hooks/commands/fun.ts b/src/app/hooks/commands/fun.ts
index d2f356d08..a4dd60b07 100644
--- a/src/app/hooks/commands/fun.ts
+++ b/src/app/hooks/commands/fun.ts
@@ -1,4 +1,5 @@
 import type { RoomMessageEventContent } from '$types/matrix-sdk';
+import { MsgType } from '$types/matrix-sdk';
 import type { CommandContext, CommandRecord } from './types';
 import { Command } from './types';
 
@@ -102,7 +103,7 @@ export const createFunCommands = (ctx: CommandContext): Partial<CommandRecord> =
       exe: async (payload) => {
         const target = payload.trim();
         await mx.sendMessage(room.roomId, {
-          msgtype: 'm.emote',
+          msgtype: MsgType.Emote,
           'm.mentions': {
             user_ids: target ? [target] : [],
           },
diff --git a/src/app/hooks/commands/misc.ts b/src/app/hooks/commands/misc.ts
index 83952551a..23da23bbe 100644
--- a/src/app/hooks/commands/misc.ts
+++ b/src/app/hooks/commands/misc.ts
@@ -1,5 +1,5 @@
 import type { RoomMessageEventContent } from '$types/matrix-sdk';
-import { MatrixError } from '$types/matrix-sdk';
+import { MatrixError, MsgType } from '$types/matrix-sdk';
 import { sendFeedback } from '$utils/sendFeedbackToUser';
 import { CustomStateEvent } from '$types/matrix/room';
 import { ErrorCode } from '../../cs-errorcode';
@@ -140,7 +140,7 @@ export const createMiscCommands = (ctx: CommandContext): Partial<CommandRecord>
 
         if (mlat && mlon)
           await mx.sendMessage(room.roomId, {
-            msgtype: 'm.location',
+            msgtype: MsgType.Location,
             geo_uri: `geo:${mlat},${mlon};u=0`,
             body: `https://www.openstreetmap.org/?mlat=${mlat}&mlon=${mlon}#map=16/${mlat}/${mlon}"`,
           } as RoomMessageEventContent);
@@ -176,7 +176,7 @@ export const createMiscCommands = (ctx: CommandContext): Partial<CommandRecord>
             return;
           }
           mx.sendMessage(room.roomId, {
-            msgtype: 'm.location',
+            msgtype: MsgType.Location,
             geo_uri: `geo:${mlat},${mlon}${malt ? `,${malt}` : ''};u=0`,
             body: `https://www.openstreetmap.org/?mlat=${mlat}&mlon=${mlon}#map=16/${mlat}/${mlon}"`,
           } as unknown as RoomMessageEventContent);
diff --git a/src/app/hooks/timeline/useProcessedTimeline.ts b/src/app/hooks/timeline/useProcessedTimeline.ts
index fcc91e1bb..d7c6bba36 100644
--- a/src/app/hooks/timeline/useProcessedTimeline.ts
+++ b/src/app/hooks/timeline/useProcessedTimeline.ts
@@ -69,27 +69,32 @@ export function getProcessedRowIndexForRawTimelineIndex(
   return bestRowIndex >= 0 ? { rowIndex: bestRowIndex, focusRawIndex: bestRawIndex } : undefined;
 }
 
+// Decrypted room-message events are re-typed to this app-internal value; there is no SDK constant for it.
+const ROOM_MESSAGE_DECRYPTED = 'm.room.message.encrypted';
+
 const MESSAGE_EVENT_TYPES = new Set([
-  'm.room.message',
-  'm.room.message.encrypted',
-  'm.sticker',
-  'm.room.encrypted',
+  EventType.RoomMessage,
+  ROOM_MESSAGE_DECRYPTED,
+  EventType.Sticker,
+  EventType.RoomMessageEncrypted,
 ]);
 
 export const STANDARD_RENDERED_EVENT_TYPES = new Set([
-  'm.room.message',
-  'm.room.message.encrypted',
-  'm.sticker',
+  EventType.RoomMessage,
+  ROOM_MESSAGE_DECRYPTED,
+  EventType.Sticker,
   M_POLL_START.name,
-  'm.room.member',
-  'm.room.name',
-  'm.room.topic',
-  'm.room.avatar',
-  'org.matrix.msc3401.call.member',
+  EventType.RoomMember,
+  EventType.RoomName,
+  EventType.RoomTopic,
+  EventType.RoomAvatar,
+  EventType.GroupCallMemberPrefix,
 ]);
 
 const normalizeMessageType = (t: string): string =>
-  t === 'm.room.encrypted' || t === 'm.room.message.encrypted' ? 'm.room.message' : t;
+  t === (EventType.RoomMessageEncrypted as string) || t === ROOM_MESSAGE_DECRYPTED
+    ? EventType.RoomMessage
+    : t;
 
 const isMessageRow = (mEvent: MatrixEvent): boolean =>
   MESSAGE_EVENT_TYPES.has(mEvent.getType()) && !isEditEvent(mEvent);
diff --git a/src/app/hooks/timeline/useTimelineActions.ts b/src/app/hooks/timeline/useTimelineActions.ts
index aee5028b4..b68a71f71 100644
--- a/src/app/hooks/timeline/useTimelineActions.ts
+++ b/src/app/hooks/timeline/useTimelineActions.ts
@@ -2,7 +2,7 @@ import type { MouseEventHandler } from 'react';
 import { useCallback } from 'react';
 import type { MatrixClient, Room, MatrixEvent } from '$types/matrix-sdk';
 import type { UserProfile } from '$hooks/useUserProfile';
-import { EventStatus } from '$types/matrix-sdk';
+import { EventStatus, RelationType } from '$types/matrix-sdk';
 import type { Editor } from 'slate';
 import { ReactEditor } from 'slate-react';
 
@@ -154,7 +154,7 @@ export function useTimelineActions({
                 userId: mx.getUserId() ?? '',
                 eventId: threadRootId,
                 body: '',
-                relation: { rel_type: 'm.thread', event_id: threadRootId },
+                relation: { rel_type: RelationType.Thread, event_id: threadRootId },
               }
             : undefined
         );
@@ -165,7 +165,7 @@ export function useTimelineActions({
       const { body, formattedBody } = extractReplyDraftBody(replyEvt, timelineSet);
 
       const { 'm.relates_to': relation } = startThread
-        ? { 'm.relates_to': { rel_type: 'm.thread', event_id: draftEventId } }
+        ? { 'm.relates_to': { rel_type: RelationType.Thread, event_id: draftEventId } }
         : replyEvt.getWireContent();
 
       const senderId = replyEvt.getSender();
diff --git a/src/app/hooks/timeline/useTimelineRendererContext.ts b/src/app/hooks/timeline/useTimelineRendererContext.ts
index ce47d892d..9b87ec892 100644
--- a/src/app/hooks/timeline/useTimelineRendererContext.ts
+++ b/src/app/hooks/timeline/useTimelineRendererContext.ts
@@ -1,5 +1,6 @@
 import { useMemo } from 'react';
 import type { Room } from '$types/matrix-sdk';
+import { EventType } from '$types/matrix-sdk';
 import type { HTMLReactParserOptions } from 'html-react-parser';
 import type { Opts as LinkifyOpts } from 'linkifyjs';
 import {
@@ -109,9 +110,9 @@ export function useTimelineRendererContext(room: Room): TimelineRendererContextV
   const creators = useRoomCreators(room);
   const permissions = useRoomPermissions(creators, powerLevels);
   const canRedact = permissions.action('redact', mx.getSafeUserId());
-  const canDeleteOwn = permissions.event('m.room.redaction', mx.getSafeUserId());
-  const canSendReaction = permissions.event('m.reaction', mx.getSafeUserId());
-  const canPinEvent = permissions.stateEvent('m.room.pinned_events', mx.getSafeUserId());
+  const canDeleteOwn = permissions.event(EventType.RoomRedaction, mx.getSafeUserId());
+  const canSendReaction = permissions.event(EventType.Reaction, mx.getSafeUserId());
+  const canPinEvent = permissions.stateEvent(EventType.RoomPinnedEvents, mx.getSafeUserId());
   const isReadOnly = !permissions.message(room.hasEncryptionStateEvent(), mx.getSafeUserId());
   const getMemberPowerTag = useGetMemberPowerTag(room, creators, powerLevels);
   const parseMemberEvent = useMemberEventParser();
diff --git a/src/app/pages/client/BackgroundNotifications.tsx b/src/app/pages/client/BackgroundNotifications.tsx
index 8f40a1443..3a9ba270b 100644
--- a/src/app/pages/client/BackgroundNotifications.tsx
+++ b/src/app/pages/client/BackgroundNotifications.tsx
@@ -346,7 +346,7 @@ export function BackgroundNotifications() {
             if (!eventId) return;
 
             const eventType = mEvent.getType();
-            const isEncryptedType = eventType === 'm.room.encrypted';
+            const isEncryptedType = eventType === (EventType.RoomMessageEncrypted as string);
 
             // For encrypted events that haven't been decrypted yet, wait for decryption
             // before processing the notification. The SDK's Timeline re-emission after
diff --git a/src/app/pages/client/client-non-ui/notifications.tsx b/src/app/pages/client/client-non-ui/notifications.tsx
index 88419c64d..80b43bc51 100644
--- a/src/app/pages/client/client-non-ui/notifications.tsx
+++ b/src/app/pages/client/client-non-ui/notifications.tsx
@@ -248,7 +248,7 @@ export function MessageNotifications() {
       // For encrypted events that haven't been decrypted yet, wait for decryption
       // before processing the notification. The SDK's Timeline re-emission after
       // decryption comes with data.liveEvent=false which would wrongly block it.
-      if (mEvent.getType() === 'm.room.encrypted' && mEvent.isEncrypted()) {
+      if (mEvent.getType() === (EventType.RoomMessageEncrypted as string) && mEvent.isEncrypted()) {
         if (eventId) {
           // Mark this event to skip focus check when decrypted, so we use the focus
           // state from when the encrypted event originally arrived, not when it decrypts.
diff --git a/src/app/plugins/call/CallEmbed.ts b/src/app/plugins/call/CallEmbed.ts
index edde57b3e..0de990d71 100644
--- a/src/app/plugins/call/CallEmbed.ts
+++ b/src/app/plugins/call/CallEmbed.ts
@@ -1,5 +1,11 @@
 import type { MatrixClient, MatrixEvent, Room } from '$types/matrix-sdk';
-import { ClientEvent, KnownMembership, MatrixEventEvent, RoomStateEvent } from '$types/matrix-sdk';
+import {
+  ClientEvent,
+  EventType,
+  KnownMembership,
+  MatrixEventEvent,
+  RoomStateEvent,
+} from '$types/matrix-sdk';
 import { invoke } from '@tauri-apps/api/core';
 import type { IRoomEvent, IWidget, WidgetDriver } from 'matrix-widget-api';
 import {
@@ -333,11 +339,11 @@ export class CallEmbed {
       });
 
       // Sliding sync may not have delivered m.room.member yet.
-      if (!this.room.currentState.getStateEvents('m.room.member', myUserId)) {
+      if (!this.room.currentState.getStateEvents(EventType.RoomMember, myUserId)) {
         const membership = this.room.getMyMembership();
         if (membership) {
           const memberRaw = {
-            type: 'm.room.member',
+            type: EventType.RoomMember,
             state_key: myUserId,
             room_id: this.roomId,
             sender: myUserId,
diff --git a/src/app/utils/messageReaction.ts b/src/app/utils/messageReaction.ts
index ae74030ad..ea71caa51 100644
--- a/src/app/utils/messageReaction.ts
+++ b/src/app/utils/messageReaction.ts
@@ -1,5 +1,6 @@
 import type { MatrixReactionEvent } from '$types/matrix/common';
-import type { MatrixClient, Room } from 'matrix-js-sdk';
+import type { MatrixClient, Room } from '$types/matrix-sdk';
+import { RelationType } from '$types/matrix-sdk';
 import { ImageUsage } from '$plugins/custom-emoji';
 import { getImagePackReferencesForMxcWrappedInMap } from './msc4459helper';
 import { MATRIX_UNSTABLE_IMAGE_SOURCE_PACK_PROPERTY_NAME } from '$unstable/prefixes';
@@ -14,7 +15,7 @@ export const getReactionContent = (
   'm.relates_to': {
     event_id: eventId,
     key,
-    rel_type: 'm.annotation',
+    rel_type: RelationType.Annotation,
   },
   shortcode,
   'com.beeper.reaction.shortcode': shortcode,
diff --git a/src/app/utils/notificationStyle.ts b/src/app/utils/notificationStyle.ts
index c06345716..dfc16091c 100644
--- a/src/app/utils/notificationStyle.ts
+++ b/src/app/utils/notificationStyle.ts
@@ -1,3 +1,5 @@
+import { EventType } from 'matrix-js-sdk/lib/@types/event';
+
 export const DEFAULT_NOTIFICATION_ICON = '/public/res/logo-maskable/logo-maskable-180x180.png';
 export const DEFAULT_NOTIFICATION_BADGE = '/public/res/logo-maskable/logo-maskable-72x72.png';
 const DEFAULT_MESSAGE_PREVIEW = 'new message';
@@ -63,7 +65,7 @@ export const resolveNotificationPreviewText = ({
     return 'Added a reaction';
   }
 
-  const encryptedContext = isEncryptedRoom || eventType === 'm.room.encrypted';
+  const encryptedContext = isEncryptedRoom || eventType === EventType.RoomMessageEncrypted;
 
   if (!showMessageContent) {
     return encryptedContext ? ENCRYPTED_MESSAGE_PREVIEW : DEFAULT_MESSAGE_PREVIEW;
diff --git a/src/app/utils/room/relations.ts b/src/app/utils/room/relations.ts
index 53de30903..56474ea7a 100644
--- a/src/app/utils/room/relations.ts
+++ b/src/app/utils/room/relations.ts
@@ -211,7 +211,6 @@ export const collectRelationEditEvents = (
 export const isRedactableMessageType = (type: string): boolean =>
   type === (EventType.RoomMessage as string) ||
   type === (EventType.RoomMessageEncrypted as string) ||
-  type === 'm.room.encrypted' ||
   type === (EventType.Sticker as string);
 
 export const getRedactionTargetId = (redactionEvent: MatrixEvent): string | undefined => {
diff --git a/src/app/utils/room/unread.ts b/src/app/utils/room/unread.ts
index 6d04eddaa..85ac4f1d4 100644
--- a/src/app/utils/room/unread.ts
+++ b/src/app/utils/room/unread.ts
@@ -1,5 +1,10 @@
 import type { IPushRule, IPushRules, MatrixClient, MatrixEvent, Room } from '$types/matrix-sdk';
-import { EventType, NotificationCountType, PushRuleActionName } from '$types/matrix-sdk';
+import {
+  EventType,
+  NotificationCountType,
+  PushRuleActionName,
+  RelationType,
+} from '$types/matrix-sdk';
 
 import type { UnreadInfo } from '$types/matrix/room';
 import { NotificationType } from '$types/matrix/room';
@@ -86,13 +91,13 @@ export const getNotificationType = (mx: MatrixClient, roomId: string): Notificat
   return NotificationType.MentionsAndKeywords;
 };
 
-const NOTIFICATION_EVENT_TYPES = new Set([
-  'm.room.create',
-  'm.room.message',
-  'm.room.encrypted',
-  'm.room.member',
-  'm.sticker',
-  'm.reaction',
+const NOTIFICATION_EVENT_TYPES = new Set<string>([
+  EventType.RoomCreate,
+  EventType.RoomMessage,
+  EventType.RoomMessageEncrypted,
+  EventType.RoomMember,
+  EventType.Sticker,
+  EventType.Reaction,
 ]);
 export const isNotificationEvent = (mEvent: MatrixEvent, room?: Room, userId?: string) => {
   const eType = mEvent.getType();
@@ -109,7 +114,7 @@ export const isNotificationEvent = (mEvent: MatrixEvent, room?: Room, userId?: s
   if (relationType === 'm.replace') return false;
 
   // For reactions: only count them if they're reactions to the current user's messages
-  if (relationType === 'm.annotation') {
+  if (relationType === RelationType.Annotation) {
     if (!room || !userId || !relation) {
       // If we don't have room/userId/relation context, filter out all reactions (safe default)
       return false;
diff --git a/src/app/utils/sendFeedbackToUser.ts b/src/app/utils/sendFeedbackToUser.ts
index 03fd3a6fa..f8b935e48 100644
--- a/src/app/utils/sendFeedbackToUser.ts
+++ b/src/app/utils/sendFeedbackToUser.ts
@@ -1,10 +1,10 @@
 import type { Room } from '$types/matrix-sdk';
-import { DuplicateStrategy, MatrixEvent } from '$types/matrix-sdk';
+import { DuplicateStrategy, EventType, MatrixEvent, MsgType } from '$types/matrix-sdk';
 
 export function sendFeedback(msg: string, room: Room, userId: string) {
   const localNotice = new MatrixEvent({
-    type: 'm.room.message',
-    content: { msgtype: 'm.notice', body: msg },
+    type: EventType.RoomMessage,
+    content: { msgtype: MsgType.Notice, body: msg },
     event_id: `~sable-feedback-${Date.now()}`,
     room_id: room.roomId,
     sender: userId,
diff --git a/src/client/presenceSync.ts b/src/client/presenceSync.ts
index 3111be8a7..4d2b9a6d8 100644
--- a/src/client/presenceSync.ts
+++ b/src/client/presenceSync.ts
@@ -1,6 +1,7 @@
 import type { CryptoBackend, IDeviceLists, IToDeviceEvent, MatrixClient } from '$types/matrix-sdk';
 import {
   ClientEvent,
+  EventType,
   Filter,
   Method,
   processToDeviceMessages,
@@ -106,7 +107,7 @@ export class PresenceSyncManager {
       if (
         typeof rawEvent !== 'object' ||
         !rawEvent ||
-        (rawEvent as Record<string, unknown>).type !== 'm.presence'
+        (rawEvent as Record<string, unknown>).type !== (EventType.Presence as string)
       )
         return;
 
@@ -137,7 +138,7 @@ export class PresenceSyncManager {
         filter.setDefinition({
           room: { rooms: [] },
           account_data: { types: [] },
-          presence: { types: ['m.presence'] },
+          presence: { types: [EventType.Presence] },
         });
 
         const filterId = await this.mx.getOrCreateFilter('presence_only', filter);
diff --git a/src/client/slidingSync.ts b/src/client/slidingSync.ts
index 7214083a5..3eec08431 100644
--- a/src/client/slidingSync.ts
+++ b/src/client/slidingSync.ts
@@ -170,8 +170,8 @@ const SPACE_REQUIRED_STATE: MSC3575RoomSubscription['required_state'] = [
   [EventType.RoomEncryption, ''],
   [EventType.RoomTombstone, ''],
   [CustomStateEvent.RoomBanner, ''],
-  ['m.space.child', MSC3575_WILDCARD],
-  ['m.space.parent', MSC3575_WILDCARD],
+  [EventType.SpaceChild, MSC3575_WILDCARD],
+  [EventType.SpaceParent, MSC3575_WILDCARD],
 ];
 
 const ACTIVE_ROOM_REQUIRED_STATE: MSC3575RoomSubscription['required_state'] = [
@@ -192,8 +192,8 @@ const ACTIVE_ROOM_REQUIRED_STATE: MSC3575RoomSubscription['required_state'] = [
   [EventType.RoomThirdPartyInvite, MSC3575_WILDCARD],
   [EventType.RoomMember, MSC3575_STATE_KEY_ME],
   [EventType.RoomMember, MSC3575_STATE_KEY_LAZY],
-  ['m.space.child', MSC3575_WILDCARD],
-  ['m.space.parent', MSC3575_WILDCARD],
+  [EventType.SpaceChild, MSC3575_WILDCARD],
+  [EventType.SpaceParent, MSC3575_WILDCARD],
   [EventType.GroupCallPrefix, ''],
   [EventType.GroupCallMemberPrefix, MSC3575_WILDCARD],
   ...Object.values(CustomStateEvent).map((type) => [type, MSC3575_WILDCARD] as [string, string]),
diff --git a/src/client/slidingSyncSidebarCache.ts b/src/client/slidingSyncSidebarCache.ts
index 098a8ff59..9ee118a35 100644
--- a/src/client/slidingSyncSidebarCache.ts
+++ b/src/client/slidingSyncSidebarCache.ts
@@ -66,7 +66,8 @@ const mergeStateEvents = (
   const merged = new Map<string, StateEvent>();
   previous?.forEach((event) => merged.set(stateEventKey(event), event));
   incoming?.forEach((event) => {
-    const cacheMember = event.type === 'm.room.member' && event.state_key === userId;
+    const cacheMember =
+      event.type === (EventType.RoomMember as string) && event.state_key === userId;
     if (cacheMember || CACHED_STATE_TYPES.has(event.type)) {
       merged.set(stateEventKey(event), event);
     }
@@ -75,7 +76,9 @@ const mergeStateEvents = (
 };
 
 const selfMembership = (events: StateEvent[] | undefined, userId: string): string | undefined => {
-  const event = events?.find((e) => e.type === 'm.room.member' && e.state_key === userId);
+  const event = events?.find(
+    (e) => e.type === (EventType.RoomMember as string) && e.state_key === userId
+  );
   const content = event?.content;
   return content && typeof content === 'object'
     ? (content as { membership?: string }).membership
diff --git a/src/sw.ts b/src/sw.ts
index 96093fcc4..8b20daea5 100644
--- a/src/sw.ts
+++ b/src/sw.ts
@@ -2,6 +2,7 @@
 
 /* oxlint-disable no-console, unicorn/require-post-message-target-origin */
 import { precacheAndRoute, cleanupOutdatedCaches } from 'workbox-precaching';
+import { EventType } from 'matrix-js-sdk/lib/@types/event';
 
 import { createPushNotifications } from './sw/pushNotification';
 import { withMediaFetchSlot } from './app/utils/mediaConcurrency';
@@ -497,7 +498,7 @@ async function handleMinimalPushPayload(
     sender_id: sender,
   };
 
-  if (eventType === 'm.room.encrypted') {
+  if (eventType === EventType.RoomMessageEncrypted) {
     // Try to relay decryption to an open app tab.
     const result =
       windowClients.length > 0
diff --git a/src/types/matrix/common.ts b/src/types/matrix/common.ts
index acef5ed08..c900deea0 100644
--- a/src/types/matrix/common.ts
+++ b/src/types/matrix/common.ts
@@ -2,6 +2,7 @@ import type { SerializableMap } from '$types/wrapper/SerializableMap';
 import type { SerializableSet } from '$types/wrapper/SerializableSet';
 import type { EncryptedAttachmentInfo } from 'browser-encrypt-attachment';
 import type { MsgType } from '$types/matrix-sdk';
+import type { RelationType } from '$types/matrix-sdk';
 import type * as prefix from '$unstable/prefixes';
 
 export type IImageInfo = {
@@ -13,7 +14,7 @@ export type IImageInfo = {
 };
 
 export type MatrixRelatesTo = {
-  rel_type: 'm.annotation';
+  rel_type: RelationType.Annotation;
   event_id: string;
   key?: string;
 };