diff --git a/frontend/public/global.css b/frontend/public/global.css
index 1131c0e..13f72a7 100644
--- a/frontend/public/global.css
+++ b/frontend/public/global.css
@@ -278,6 +278,79 @@ body {
 	font-size: 0.833rem;
 }
 
+/* sidebar */
+
+.sidebar-container {
+	display: flex;
+	flex-direction: column;
+	background-color: var(--background-color-0);
+	height: 100%;
+	min-width: 255px;
+	max-width: 255px;
+}
+
+@media screen and (max-width: 768px) {
+	.sidebar-container {
+		flex-basis: 100%;
+		min-width: unset;
+		max-width: unset;
+	}
+}
+
+.sidebar {
+	width: 100%;
+	height: 100%;
+	padding: var(--space-xs);
+	overflow-x: hidden;
+	overflow-y: auto;
+}
+
+.sidebar-button {
+	flex-shrink: 0;
+	display: flex;
+	align-items: center;
+	justify-content: left;
+	border: none;
+	background-color: var(--background-color-0);
+	padding: var(--space-xs);
+	margin-bottom: var(--space-xxs);
+	color: currentColor;
+	font: inherit;
+	border-radius: var(--radius-md);
+	width: 100%;
+	max-height: 3.4em;
+}
+
+.sidebar-button span {
+	margin-left: var(--space-xxs);
+	white-space: nowrap;
+	overflow: hidden;
+	text-overflow: ellipsis;
+}
+
+.sidebar-button div {
+	display: inline;
+	flex-shrink: 0;
+
+	/* TODO: HACK! */
+	width: 24px;
+	height: 24px;
+}
+
+.sidebar-button .icon-button {
+	visibility: hidden;
+}
+
+.sidebar-button.selected .icon-button,
+.sidebar-button:hover .icon-button {
+	visibility: visible;
+}
+
+.sidebar-button.selected,
+.sidebar-button:hover {
+	background-color: var(--background-color-2);
+}
+
 /*! the tweaks below are heavily based on modern-normalize v1.1.0 | MIT License | https://github.com/sindresorhus/modern-normalize */
 
 *,
diff --git a/frontend/src/components/ChannelTopBar.svelte b/frontend/src/components/ChannelTopBar.svelte
index bd71aa2..e395730 100644
--- a/frontend/src/components/ChannelTopBar.svelte
+++ b/frontend/src/components/ChannelTopBar.svelte
@@ -1,7 +1,7 @@
 <script>
-    import { HashIcon, MenuIcon } from "svelte-feather-icons";
+    import { HashIcon, MenuIcon, UsersIcon } from "svelte-feather-icons";
     import { getItem } from "../storage";
-    import { overlayStore, showSidebar } from "../stores";
+    import { overlayStore, showPresenceSidebar, showSidebar } from "../stores";
 
     export let channel;
 </script>
@@ -10,6 +10,11 @@
     .menu-button {
         margin-right: var(--space-md);
     }
+
+    .right-buttons {
+        margin-left: auto;
+        margin-right: var(--space-xs);
+    }
 </style>
 
 <div class="top-bar">
@@ -20,4 +25,9 @@
     {/if}
     <HashIcon />
     <span class="h5 top-bar-heading" on:click="{ () => overlayStore.open('editChannel', {channel}) }">{ channel.name }</span>
+    <div class="right-buttons">
+        <button class="icon-button" on:click="{ () => showPresenceSidebar.set(!showPresenceSidebar.value) }" aria-label="Toggle user list">
+            <UsersIcon />
+        </button>
+    </div>
 </div>
diff --git a/frontend/src/components/Main.svelte b/frontend/src/components/Main.svelte
index 16b1f1e..41a1c5d 100644
--- a/frontend/src/components/Main.svelte
+++ b/frontend/src/components/Main.svelte
@@ -1,8 +1,9 @@
 <script>
     import { CloudIcon } from "svelte-feather-icons";
-    import { gatewayStatus, showSidebar, selectedChannel, smallViewport, showChannelView, theme } from "../stores";
+    import { gatewayStatus, showSidebar, selectedChannel, smallViewport, showChannelView, theme, showPresenceSidebar } from "../stores";
     import ChannelView from "./ChannelView.svelte";
     import OverlayProvider from "./overlays/OverlayProvider.svelte";
+    import PresenceSidebar from "./PresenceSidebar.svelte";
     import Sidebar from "./Sidebar.svelte";
 </script>
 
@@ -48,7 +49,10 @@
     {#if $showSidebar || $selectedChannel.id === -1}
         <Sidebar />
     {/if}
-    {#if !($smallViewport && $showSidebar) && $showChannelView && $selectedChannel.id !== -1}
+    {#if !($smallViewport && $showSidebar) && !($smallViewport && $showPresenceSidebar) && $showChannelView && $selectedChannel.id !== -1}
         <ChannelView channel={$selectedChannel} />
     {/if}
+    {#if $showPresenceSidebar}
+        <PresenceSidebar />
+    {/if}
 </div>
diff --git a/frontend/src/components/PresenceSidebar.svelte b/frontend/src/components/PresenceSidebar.svelte
new file mode 100644
index 0000000..36b990d
--- /dev/null
+++ b/frontend/src/components/PresenceSidebar.svelte
@@ -0,0 +1,47 @@
+<script>
+    import { ArrowLeftIcon, AtSignIcon } from "svelte-feather-icons";
+    import { quadInOut } from "svelte/easing";
+    import { maybeFly } from "../animations";
+    import { presenceStore, showChannelView, showPresenceSidebar, smallViewport } from "../stores";
+
+    let pendingExit = false;
+
+    const scheduleClose = () => {
+        if ($smallViewport) {
+            $showChannelView = false;
+            pendingExit = true;
+        }
+        $showPresenceSidebar = false;
+    };
+
+    const outroEnd = () => {
+        if (pendingExit) {
+            pendingExit = false;
+            $showChannelView = true;
+        }
+    };
+</script>
+
+<div class="sidebar-container" transition:maybeFly="{{ duration: 200, easing: quadInOut, x: 10 }}" on:outroend="{ outroEnd }">
+    <div class="top-bar">
+        <span class="input-label">User List</span>
+    </div>
+    <div class="sidebar">
+        {#each $presenceStore as entry}
+            <button class="sidebar-button">
+                <div>
+                    <AtSignIcon />
+                </div>
+                <span>{ entry.user.username }</span>
+            </button>
+        {/each}
+        {#if $smallViewport}
+            <button on:click={ scheduleClose } class="sidebar-button">
+                <div>
+                    <ArrowLeftIcon />
+                </div>
+                <span>Back</span>
+            </button>
+        {/if}
+    </div>
+</div>
diff --git a/frontend/src/components/Sidebar.svelte b/frontend/src/components/Sidebar.svelte
index d2d9548..16ba48f 100644
--- a/frontend/src/components/Sidebar.svelte
+++ b/frontend/src/components/Sidebar.svelte
@@ -78,74 +78,4 @@
         margin-left: auto;
     }
 
-    .sidebar-container {
-        display: flex;
-        flex-direction: column;
-        background-color: var(--background-color-0);
-        height: 100%;
-        min-width: 255px;
-        max-width: 255px;
-    }
-
-    @media screen and (max-width: 768px) {
-        .sidebar-container {
-            flex-basis: 100%;
-            min-width: unset;
-            max-width: unset;
-        }
-    }
-
-    .sidebar {
-        width: 100%;
-        height: 100%;
-        padding: var(--space-xs);
-        overflow-x: hidden;
-        overflow-y: auto;
-    }
-
-    .sidebar-button {
-        flex-shrink: 0;
-        display: flex;
-        align-items: center;
-        justify-content: left;
-        border: none;
-        background-color: var(--background-color-0);
-        padding: var(--space-xs);
-        margin-bottom: var(--space-xxs);
-        color: currentColor;
-        font: inherit;
-        border-radius: var(--radius-md);
-        width: 100%;
-        max-height: 3.4em;
-    }
-
-    .sidebar-button span {
-        margin-left: var(--space-xxs);
-        white-space: nowrap;
-        overflow: hidden;
-        text-overflow: ellipsis;
-    }
-
-    .sidebar-button div {
-        display: inline;
-        flex-shrink: 0;
-
-        /* TODO: HACK! */
-        width: 24px;
-        height: 24px;
-    }
-
-    .sidebar-button .icon-button {
-        visibility: hidden;
-    }
-
-    .sidebar-button.selected .icon-button,
-    .sidebar-button:hover .icon-button {
-        visibility: visible;
-    }
-
-    .sidebar-button.selected,
-    .sidebar-button:hover {
-        background-color: var(--background-color-2);
-    }
 </style>
diff --git a/frontend/src/gateway.js b/frontend/src/gateway.js
index e190e83..e7a6d61 100644
--- a/frontend/src/gateway.js
+++ b/frontend/src/gateway.js
@@ -27,6 +27,8 @@ export const GatewayPayloadType = {
     MessageDelete: 122,
 
     TypingStart: 130,
+
+    PresenceUpdate: 140
 }
 
 export const GatewayEventType = {
@@ -37,6 +39,11 @@ export const GatewayEventType = {
     BadAuth: -3,
 }
 
+export const GatewayPresenceStatus = {
+    Offline: 0,
+    Online: 1
+}
+
 const log = logger("Gateway");
 
 export default {
diff --git a/frontend/src/stores.js b/frontend/src/stores.js
index 48d41af..e494729 100644
--- a/frontend/src/stores.js
+++ b/frontend/src/stores.js
@@ -1,4 +1,4 @@
-import gateway, { GatewayEventType, GatewayPayloadType } from "./gateway";
+import gateway, { GatewayEventType, GatewayPayloadType, GatewayPresenceStatus } from "./gateway";
 import logger from "./logging";
 import request from "./request";
 import { apiRoute, getItem, setItem } from "./storage";
@@ -398,8 +398,45 @@ class TypingStore extends Store {
     }
 }
 
+class PresenceStore extends Store {
+    constructor() {
+        super([], "PresenceStore");
+
+        gateway.subscribe(GatewayEventType.Ready, ({ presence }) => {
+            this.ingestPresenceUpdate(presence);
+        });
+
+        gateway.subscribe(GatewayEventType.PresenceUpdate, (data) => {
+            this.ingestPresenceUpdate(data);
+        });
+    }
+
+    entryIndexByUserId(userId) {
+        return this.value.findIndex(a => a.user.id === userId);
+    }
+
+    ingestPresenceUpdate(payload) {
+        payload.forEach((entry) => {
+            const existingEntry = this.entryIndexByUserId(entry.user.id);
+            if (existingEntry !== -1 && entry.status === GatewayPresenceStatus.Offline) {
+                this.value.splice(existingEntry, 1);
+            } else if (existingEntry !== -1 && entry.status !== GatewayPresenceStatus.Offline) {
+                this.value[existingEntry] = entry;
+            } else {
+                // don't need to push the status, since we remove offline members from the presence list
+                this.value.push({
+                    user: entry.user
+                });
+            }
+        });
+        console.log(this.value);
+        this.updated();
+    }
+}
+
 export const selectedChannel = new Store({ id: -1, name: "none", creator_id: -1 }, "selectedChannel");
 export const showSidebar = new Store(true, "showSidebar");
+export const showPresenceSidebar = new Store(false, "showPresenceSidebar");
 export const smallViewport = new Store(false, "smallViewport");
 export const showChannelView = new Store(true, "showChannelView");
 export const theme = new StorageItemStore("ui:theme");
@@ -410,10 +447,12 @@ export const messagesStoreProvider = new MessagesStoreProvider();
 export const userInfoStore = new UserInfoStore();
 export const overlayStore = new OverlayStore();
 export const typingStore = new TypingStore();
+export const presenceStore = new PresenceStore();
 
 export const allStores = {
     selectedChannel,
     showSidebar,
+    showPresenceSidebar,
     showChannelView,
     smallViewport,
     theme,
diff --git a/src/gateway/gatewaypayloadtype.ts b/src/gateway/gatewaypayloadtype.ts
index b8bdc16..9320c2c 100644
--- a/src/gateway/gatewaypayloadtype.ts
+++ b/src/gateway/gatewaypayloadtype.ts
@@ -1,8 +1,8 @@
 export enum GatewayPayloadType {
     Hello = 0,
-    Authenticate,
+    Authenticate, // client
     Ready,
-    Ping,
+    Ping, // client
 
     ChannelCreate = 110,
     ChannelUpdate,
@@ -13,4 +13,11 @@ export enum GatewayPayloadType {
     MessageDelete,
 
     TypingStart = 130,
+
+    PresenceUpdate = 140,
+}
+
+export enum GatewayPresenceStatus {
+    Offline = 0,
+    Online,
 }
diff --git a/src/gateway/gatewaypresence.ts b/src/gateway/gatewaypresence.ts
new file mode 100644
index 0000000..286af4c
--- /dev/null
+++ b/src/gateway/gatewaypresence.ts
@@ -0,0 +1,9 @@
+import { GatewayPresenceStatus } from "./gatewaypayloadtype"
+
+export interface GatewayPresenceEntry {
+    user: {
+        username: string,
+        id: number
+    },
+    status: GatewayPresenceStatus
+}
diff --git a/src/gateway/index.ts b/src/gateway/index.ts
index 8f039cb..a54d602 100644
--- a/src/gateway/index.ts
+++ b/src/gateway/index.ts
@@ -5,7 +5,8 @@ import { decodeTokenOrNull, getPublicUserObject } from "../auth";
 import { query } from "../database";
 import { gatewayErrors } from "../errors";
 import { GatewayPayload } from "../types/gatewaypayload";
-import { GatewayPayloadType } from "./gatewaypayloadtype";
+import { GatewayPayloadType, GatewayPresenceStatus } from "./gatewaypayloadtype";
+import { GatewayPresenceEntry } from "./gatewaypresence";
 
 const GATEWAY_BATCH_INTERVAL = 50000;
 const GATEWAY_PING_INTERVAL = 40000;
@@ -16,7 +17,7 @@ const MAX_GATEWAY_SESSIONS_PER_USER = 5;
 const dispatchChannels = new Map<string, Set<WebSocket>>();
 
 // mapping between a user id and the websocket sessions it has
-const sessionsByUserId = new Map<number, Set<WebSocket>>();
+const sessionsByUserId = new Map<number, WebSocket[]>();
 
 function clientSubscribe(ws: WebSocket, dispatchChannel: string) {
     ws.state.dispatchChannels.add(dispatchChannel);
@@ -71,7 +72,9 @@ export function dispatch(channel: string, message: GatewayPayload) {
     if (!members) return;
         
     members.forEach(e => {
-        e.send(JSON.stringify(message));
+        if (e.state.ready) {
+            e.send(JSON.stringify(message));
+        }
     });
 }
 
@@ -120,6 +123,35 @@ function sendPayload(ws: WebSocket, payload: GatewayPayload) {
     ws.send(JSON.stringify(payload));
 }
 
+function getPresenceEntryForUser(user: User, status: GatewayPresenceStatus): GatewayPresenceEntry {
+    return {
+        user: {
+            id: user.id,
+            username: user.username
+        },
+        status
+    }
+}
+
+// The initial presence entries are sent right when the user connects.
+// In the future, each user will have their own list of channels that they can join and leave.
+// In that case, we will send the presence entries to a certain user only for the channels they're in.
+function getInitialPresenceEntries(): GatewayPresenceEntry[] {
+    const entries: GatewayPresenceEntry[] = [];
+
+    sessionsByUserId.forEach((wsList: WebSocket[], userId: number) => {
+        if (wsList.length < 1)
+            return;
+
+        const firstWs = wsList[0];
+        if (firstWs.state.ready && firstWs.state.user) {
+            entries.push(getPresenceEntryForUser(firstWs.state.user, GatewayPresenceStatus.Online));
+        }
+    });
+
+    return entries;
+}
+
 export default function(server: Server) {
     const wss = new WebSocketServer({ server });
 
@@ -163,12 +195,20 @@ export default function(server: Server) {
 
         ws.on("close", () => {
             clientUnsubscribeAll(ws);
+            ws.state.ready = false;
             if (ws.state.user && ws.state.user.id) {
                 const sessions = sessionsByUserId.get(ws.state.user.id);
                 if (sessions) {
-                    sessions.delete(ws);
-                    if (sessions.size < 1) {
+                    const index = sessions.indexOf(ws);
+                    sessions.splice(index, 1);
+                    if (sessions.length < 1) {
                         sessionsByUserId.delete(ws.state.user.id);
+
+                        // user no longer has any sessions, update presence
+                        dispatch("*", {
+                            t: GatewayPayloadType.PresenceUpdate,
+                            d: [getPresenceEntryForUser(ws.state.user, GatewayPresenceStatus.Offline)]
+                        });
                     }
                 }
             }
@@ -211,14 +251,14 @@ export default function(server: Server) {
 
                     let sessions = sessionsByUserId.get(user.id);
                     if (sessions) {
-                        if ((sessions.size + 1) > MAX_GATEWAY_SESSIONS_PER_USER) {
+                        if ((sessions.length + 1) > MAX_GATEWAY_SESSIONS_PER_USER) {
                             return closeWithError(ws, gatewayErrors.TOO_MANY_SESSIONS);
                         }
                     } else {
-                        sessions = new Set();
+                        sessions = [];
                         sessionsByUserId.set(user.id, sessions);
                     }
-                    sessions.add(ws);
+                    sessions.push(ws);
 
                     // TODO: each user should have their own list of channels that they join
                     const channels = await query("SELECT id, name, owner_id FROM channels ORDER BY id ASC");
@@ -233,15 +273,25 @@ export default function(server: Server) {
                     });
 
                     ws.state.user = user;
+
+                    // first session, notify others that we are online
+                    if (sessions.length === 1) {
+                        dispatch("*", {
+                            t: GatewayPayloadType.PresenceUpdate,
+                            d: [getPresenceEntryForUser(ws.state.user, GatewayPresenceStatus.Online)]
+                        });
+                    }
+
                     ws.state.ready = true;
 
                     sendPayload(ws, {
                         t: GatewayPayloadType.Ready,
                         d: {
                             user: getPublicUserObject(ws.state.user),
-                            channels: channels.rows
+                            channels: channels.rows,
+                            presence: getInitialPresenceEntries()
                         }
-                    })
+                    });
                     break;
                 }
                 case GatewayPayloadType.Ping: {