diff --git a/src/SlashCommands.tsx b/src/SlashCommands.tsx
index fd157b2b4c..d81da80e8d 100644
--- a/src/SlashCommands.tsx
+++ b/src/SlashCommands.tsx
@@ -41,6 +41,8 @@ import { parseFragment as parseHtml } from "parse5";
 import sendBugReport from "./rageshake/submit-rageshake";
 import SdkConfig from "./SdkConfig";
 import { ensureDMExists } from "./createRoom";
+import { ViewUserPayload } from "./dispatcher/payloads/ViewUserPayload";
+import { Action } from "./dispatcher/actions";
 
 // XXX: workaround for https://github.com/microsoft/TypeScript/issues/31816
 interface HTMLInputEvent extends Event {
@@ -943,8 +945,10 @@ export const Commands = [
             }
 
             const member = MatrixClientPeg.get().getRoom(roomId).getMember(userId);
-            dis.dispatch({
-                action: 'view_user',
+            dis.dispatch<ViewUserPayload>({
+                action: Action.ViewUser,
+                // XXX: We should be using a real member object and not assuming what the
+                // receiver wants.
                 member: member || {userId},
             });
             return success();
diff --git a/src/components/structures/MatrixChat.tsx b/src/components/structures/MatrixChat.tsx
index 973d301420..d368b2c23a 100644
--- a/src/components/structures/MatrixChat.tsx
+++ b/src/components/structures/MatrixChat.tsx
@@ -17,12 +17,11 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
-import React, {createRef} from 'react';
-import {InvalidStoreError} from "matrix-js-sdk/src/errors";
-import {RoomMember} from "matrix-js-sdk/src/models/room-member";
-import {MatrixEvent} from "matrix-js-sdk/src/models/event";
+import React, { createRef } from 'react';
+import { InvalidStoreError } from "matrix-js-sdk/src/errors";
+import { RoomMember } from "matrix-js-sdk/src/models/room-member";
+import { MatrixEvent } from "matrix-js-sdk/src/models/event";
 import { isCryptoAvailable } from 'matrix-js-sdk/src/crypto';
-
 // focus-visible is a Polyfill for the :focus-visible CSS pseudo-attribute used by _AccessibleButton.scss
 import 'focus-visible';
 // what-input helps improve keyboard accessibility
@@ -30,7 +29,7 @@ import 'what-input';
 
 import Analytics from "../../Analytics";
 import { DecryptionFailureTracker } from "../../DecryptionFailureTracker";
-import {MatrixClientPeg} from "../../MatrixClientPeg";
+import { MatrixClientPeg } from "../../MatrixClientPeg";
 import PlatformPeg from "../../PlatformPeg";
 import SdkConfig from "../../SdkConfig";
 import * as RoomListSorter from "../../RoomListSorter";
@@ -40,7 +39,7 @@ import Notifier from '../../Notifier';
 import Modal from "../../Modal";
 import Tinter from "../../Tinter";
 import * as sdk from '../../index';
-import { showStartChatInviteDialog, showRoomInviteDialog } from '../../RoomInvite';
+import { showRoomInviteDialog, showStartChatInviteDialog } from '../../RoomInvite';
 import * as Rooms from '../../Rooms';
 import linkifyMatrix from "../../linkify-matrix";
 import * as Lifecycle from '../../Lifecycle';
@@ -52,21 +51,22 @@ import { getHomePageUrl } from '../../utils/pages';
 import createRoom from "../../createRoom";
 import KeyRequestHandler from '../../KeyRequestHandler';
 import { _t, getCurrentLanguage } from '../../languageHandler';
-import SettingsStore, {SettingLevel} from "../../settings/SettingsStore";
+import SettingsStore, { SettingLevel } from "../../settings/SettingsStore";
 import ThemeController from "../../settings/controllers/ThemeController";
 import { startAnyRegistrationFlow } from "../../Registration.js";
 import { messageForSyncError } from '../../utils/ErrorUtils';
 import ResizeNotifier from "../../utils/ResizeNotifier";
-import { ValidatedServerConfig } from "../../utils/AutoDiscoveryUtils";
-import AutoDiscoveryUtils from "../../utils/AutoDiscoveryUtils";
+import AutoDiscoveryUtils, { ValidatedServerConfig } from "../../utils/AutoDiscoveryUtils";
 import DMRoomMap from '../../utils/DMRoomMap';
 import { countRoomsWithNotif } from '../../RoomNotifs';
 import { ThemeWatcher } from "../../theme";
 import { storeRoomAliasInCache } from '../../RoomAliasCache';
-import {defer, IDeferred} from "../../utils/promise";
+import { defer, IDeferred } from "../../utils/promise";
 import ToastStore from "../../stores/ToastStore";
 import * as StorageManager from "../../utils/StorageManager";
 import type LoggedInViewType from "./LoggedInView";
+import { ViewUserPayload } from "../../dispatcher/payloads/ViewUserPayload";
+import { Action } from "../../dispatcher/actions";
 
 /** constants for MatrixChat.state.view */
 export enum Views {
@@ -1755,8 +1755,8 @@ export default class MatrixChat extends React.PureComponent<IProps, IState> {
 
         const member = new RoomMember(null, userId);
         if (!member) { return; }
-        dis.dispatch({
-            action: 'view_user',
+        dis.dispatch<ViewUserPayload>({
+            action: Action.ViewUser,
             member: member,
         });
     }
diff --git a/src/components/structures/RightPanel.js b/src/components/structures/RightPanel.js
index c6c330a202..56cc92a8f8 100644
--- a/src/components/structures/RightPanel.js
+++ b/src/components/structures/RightPanel.js
@@ -30,6 +30,7 @@ import SettingsStore from "../../settings/SettingsStore";
 import {RIGHT_PANEL_PHASES, RIGHT_PANEL_PHASES_NO_ARGS} from "../../stores/RightPanelStorePhases";
 import RightPanelStore from "../../stores/RightPanelStore";
 import MatrixClientContext from "../../contexts/MatrixClientContext";
+import {Action} from "../../dispatcher/actions";
 
 export default class RightPanel extends React.Component {
     static get propTypes() {
@@ -237,7 +238,7 @@ export default class RightPanel extends React.Component {
                             // within a room, so go back to the member panel if we were in the encryption panel,
                             // or the member list if we were in the member panel... phew.
                             dis.dispatch({
-                                action: "view_user",
+                                action: Action.ViewUser,
                                 member: this.state.phase === RIGHT_PANEL_PHASES.EncryptionPanel ?
                                     this.state.member : null,
                             });
@@ -266,7 +267,7 @@ export default class RightPanel extends React.Component {
                 if (SettingsStore.getValue("feature_cross_signing")) {
                     const onClose = () => {
                         dis.dispatch({
-                            action: "view_user",
+                            action: Action.ViewUser,
                             member: null,
                         });
                     };
diff --git a/src/components/views/avatars/MemberAvatar.js b/src/components/views/avatars/MemberAvatar.js
index 89314cfef7..d28d80e62a 100644
--- a/src/components/views/avatars/MemberAvatar.js
+++ b/src/components/views/avatars/MemberAvatar.js
@@ -21,6 +21,7 @@ import createReactClass from 'create-react-class';
 import * as Avatar from '../../../Avatar';
 import * as sdk from "../../../index";
 import dis from "../../../dispatcher/dispatcher";
+import {Action} from "../../../dispatcher/actions";
 
 export default createReactClass({
     displayName: 'MemberAvatar',
@@ -33,7 +34,7 @@ export default createReactClass({
         resizeMethod: PropTypes.string,
         // The onClick to give the avatar
         onClick: PropTypes.func,
-        // Whether the onClick of the avatar should be overriden to dispatch 'view_user'
+        // Whether the onClick of the avatar should be overriden to dispatch `Action.ViewUser`
         viewUserOnClick: PropTypes.bool,
         title: PropTypes.string,
     },
@@ -85,7 +86,7 @@ export default createReactClass({
         if (viewUserOnClick) {
             onClick = () => {
                 dis.dispatch({
-                    action: 'view_user',
+                    action: Action.ViewUser,
                     member: this.props.member,
                 });
             };
diff --git a/src/components/views/elements/Pill.js b/src/components/views/elements/Pill.js
index 3e4ddb99e8..03a1aeed85 100644
--- a/src/components/views/elements/Pill.js
+++ b/src/components/views/elements/Pill.js
@@ -26,6 +26,7 @@ import {MatrixClientPeg} from '../../../MatrixClientPeg';
 import FlairStore from "../../../stores/FlairStore";
 import {getPrimaryPermalinkEntity} from "../../../utils/permalinks/Permalinks";
 import MatrixClientContext from "../../../contexts/MatrixClientContext";
+import {Action} from "../../../dispatcher/actions";
 
 // For URLs of matrix.to links in the timeline which have been reformatted by
 // HttpUtils transformTags to relative links. This excludes event URLs (with `[^\/]*`)
@@ -191,7 +192,7 @@ const Pill = createReactClass({
 
     onUserPillClicked: function() {
         dis.dispatch({
-            action: 'view_user',
+            action: Action.ViewUser,
             member: this.state.member,
         });
     },
diff --git a/src/components/views/groups/GroupMemberInfo.js b/src/components/views/groups/GroupMemberInfo.js
index 0d08771676..2582cab573 100644
--- a/src/components/views/groups/GroupMemberInfo.js
+++ b/src/components/views/groups/GroupMemberInfo.js
@@ -28,6 +28,7 @@ import GroupStore from '../../../stores/GroupStore';
 import AccessibleButton from '../elements/AccessibleButton';
 import MatrixClientContext from "../../../contexts/MatrixClientContext";
 import AutoHideScrollbar from "../../structures/AutoHideScrollbar";
+import {Action} from "../../../dispatcher/actions";
 
 export default createReactClass({
     displayName: 'GroupMemberInfo',
@@ -103,7 +104,7 @@ export default createReactClass({
                 ).then(() => {
                     // return to the user list
                     dis.dispatch({
-                        action: "view_user",
+                        action: Action.ViewUser,
                         member: null,
                     });
                 }).catch((e) => {
@@ -124,7 +125,7 @@ export default createReactClass({
     _onCancel: function(e) {
         // Go back to the user list
         dis.dispatch({
-            action: "view_user",
+            action: Action.ViewUser,
             member: null,
         });
     },
diff --git a/src/components/views/right_panel/GroupHeaderButtons.js b/src/components/views/right_panel/GroupHeaderButtons.js
index f164b6c578..33d9325433 100644
--- a/src/components/views/right_panel/GroupHeaderButtons.js
+++ b/src/components/views/right_panel/GroupHeaderButtons.js
@@ -23,6 +23,8 @@ import { _t } from '../../../languageHandler';
 import HeaderButton from './HeaderButton';
 import HeaderButtons, {HEADER_KIND_GROUP} from './HeaderButtons';
 import {RIGHT_PANEL_PHASES} from "../../../stores/RightPanelStorePhases";
+import {Action} from "../../../dispatcher/actions";
+import {ActionPayload} from "../../../dispatcher/payloads";
 
 const GROUP_PHASES = [
     RIGHT_PANEL_PHASES.GroupMemberInfo,
@@ -40,10 +42,10 @@ export default class GroupHeaderButtons extends HeaderButtons {
         this._onRoomsClicked = this._onRoomsClicked.bind(this);
     }
 
-    onAction(payload) {
+    onAction(payload: ActionPayload) {
         super.onAction(payload);
 
-        if (payload.action === "view_user") {
+        if (payload.action === Action.ViewUser) {
             if (payload.member) {
                 this.setPhase(RIGHT_PANEL_PHASES.RoomMemberInfo, {member: payload.member});
             } else {
diff --git a/src/components/views/right_panel/RoomHeaderButtons.js b/src/components/views/right_panel/RoomHeaderButtons.js
index bad89e2dbe..838727981d 100644
--- a/src/components/views/right_panel/RoomHeaderButtons.js
+++ b/src/components/views/right_panel/RoomHeaderButtons.js
@@ -23,6 +23,8 @@ import { _t } from '../../../languageHandler';
 import HeaderButton from './HeaderButton';
 import HeaderButtons, {HEADER_KIND_ROOM} from './HeaderButtons';
 import {RIGHT_PANEL_PHASES} from "../../../stores/RightPanelStorePhases";
+import {Action} from "../../../dispatcher/actions";
+import {ActionPayload} from "../../../dispatcher/payloads";
 
 const MEMBER_PHASES = [
     RIGHT_PANEL_PHASES.RoomMemberList,
@@ -39,9 +41,9 @@ export default class RoomHeaderButtons extends HeaderButtons {
         this._onNotificationsClicked = this._onNotificationsClicked.bind(this);
     }
 
-    onAction(payload) {
+    onAction(payload: ActionPayload) {
         super.onAction(payload);
-        if (payload.action === "view_user") {
+        if (payload.action === Action.ViewUser) {
             if (payload.member) {
                 this.setPhase(RIGHT_PANEL_PHASES.RoomMemberInfo, {member: payload.member});
             } else {
diff --git a/src/components/views/right_panel/UserInfo.js b/src/components/views/right_panel/UserInfo.js
index daf1a9490d..0392746c94 100644
--- a/src/components/views/right_panel/UserInfo.js
+++ b/src/components/views/right_panel/UserInfo.js
@@ -44,6 +44,7 @@ import {RIGHT_PANEL_PHASES} from "../../../stores/RightPanelStorePhases";
 import EncryptionPanel from "./EncryptionPanel";
 import { useAsyncMemo } from '../../../hooks/useAsyncMemo';
 import { verifyUser, legacyVerifyUser, verifyDevice } from '../../../verification';
+import {Action} from "../../../dispatcher/actions";
 
 const _disambiguateDevices = (devices) => {
     const names = Object.create(null);
@@ -841,7 +842,7 @@ const GroupAdminToolsSection = ({children, groupId, groupMember, startUpdating,
             cli.removeUserFromGroup(groupId, groupMember.userId).then(() => {
                 // return to the user list
                 dis.dispatch({
-                    action: "view_user",
+                    action: Action.ViewUser,
                     member: null,
                 });
             }).catch((e) => {
diff --git a/src/components/views/rooms/MemberInfo.js b/src/components/views/rooms/MemberInfo.js
index 5d8e03a050..ed6c4ad748 100644
--- a/src/components/views/rooms/MemberInfo.js
+++ b/src/components/views/rooms/MemberInfo.js
@@ -48,6 +48,7 @@ import E2EIcon from "./E2EIcon";
 import AutoHideScrollbar from "../../structures/AutoHideScrollbar";
 import {MatrixClientPeg} from "../../../MatrixClientPeg";
 import MatrixClientContext from "../../../contexts/MatrixClientContext";
+import {Action} from "../../../dispatcher/actions";
 
 export default createReactClass({
     displayName: 'MemberInfo',
@@ -724,7 +725,7 @@ export default createReactClass({
 
     onCancel: function(e) {
         dis.dispatch({
-            action: "view_user",
+            action: Action.ViewUser,
             member: null,
         });
     },
diff --git a/src/components/views/rooms/MemberTile.js b/src/components/views/rooms/MemberTile.js
index 6842e27ed3..2d290564c3 100644
--- a/src/components/views/rooms/MemberTile.js
+++ b/src/components/views/rooms/MemberTile.js
@@ -23,6 +23,7 @@ import * as sdk from "../../../index";
 import dis from "../../../dispatcher/dispatcher";
 import { _t } from '../../../languageHandler';
 import { MatrixClientPeg } from "../../../MatrixClientPeg";
+import {Action} from "../../../dispatcher/actions";
 
 export default createReactClass({
     displayName: 'MemberTile',
@@ -185,7 +186,7 @@ export default createReactClass({
 
     onClick: function(e) {
         dis.dispatch({
-            action: 'view_user',
+            action: Action.ViewUser,
             member: this.props.member,
         });
     },
diff --git a/src/dispatcher/actions.ts b/src/dispatcher/actions.ts
index ff1650e4e5..880e7e62cd 100644
--- a/src/dispatcher/actions.ts
+++ b/src/dispatcher/actions.ts
@@ -19,5 +19,19 @@ export type DispatcherAction = Action | string;
 
 export enum Action {
     // TODO: Populate with actual actions
+    // This is lazily generated as it also includes fixing a bunch of references. Work
+    // that we don't really want to take on in a giant chunk. We should always define
+    // new actions here, and ideally when we touch existing ones we take some time to
+    // define them correctly.
+
+    // When defining a new action, please use lower_scored_case with an optional class
+    // name prefix. For example, `RoomListStore.view_room` or `view_user_settings`.
+    // New definitions should also receive an accompanying interface in the payloads
+    // directory.
+
+    /**
+     * View a user's profile. Should be used with a ViewUserPayload.
+     */
+    ViewUser = "view_user",
 }
 
diff --git a/src/dispatcher/dispatcher.ts b/src/dispatcher/dispatcher.ts
index 6ef165c485..8330e5cd19 100644
--- a/src/dispatcher/dispatcher.ts
+++ b/src/dispatcher/dispatcher.ts
@@ -32,7 +32,7 @@ export class MatrixDispatcher extends Dispatcher<ActionPayload> {
      *        an operation that the browser requires user interaction
      *        for. Default false (async).
      */
-    dispatch(payload: ActionPayload, sync = false) {
+    dispatch<T extends ActionPayload>(payload: T, sync = false) {
         if (payload instanceof AsyncActionPayload) {
             payload.fn((action: ActionPayload) => {
                 this.dispatch(action, sync);
diff --git a/src/dispatcher/payloads/ViewUserPayload.ts b/src/dispatcher/payloads/ViewUserPayload.ts
new file mode 100644
index 0000000000..ed602d4e24
--- /dev/null
+++ b/src/dispatcher/payloads/ViewUserPayload.ts
@@ -0,0 +1,29 @@
+/*
+Copyright 2020 The Matrix.org Foundation C.I.C.
+
+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 { RoomMember } from "matrix-js-sdk/src/models/room-member";
+import { ActionPayload } from "../payloads";
+import { Action } from "../actions";
+
+export interface ViewUserPayload extends ActionPayload {
+    action: Action.ViewUser,
+
+    /**
+     * The member to view. May be null or falsy to indicate that no member
+     * should be shown (hide whichever relevant components).
+     */
+    member?: RoomMember;
+}