diff --git a/frontend/src/App.tsx b/frontend/src/App.tsx
index c4c86da..599f495 100644
--- a/frontend/src/App.tsx
+++ b/frontend/src/App.tsx
@@ -1,8 +1,127 @@
+import { useEffect, useRef, useState } from "react";
+import { listMessages } from "./api/client";
+import type { DashboardMessage } from "./api/client";
+import { connectDashboardSocket } from "./ws/client";
+import type { DashboardEvent } from "./ws/client";
+
+interface MessageItem {
+  id: string;
+  channel_id: string;
+  user_id: string;
+  username: string;
+  avatar_url: string | null;
+  content: string;
+  created_at: number;
+  type: "text" | "edited" | "deleted";
+}
+
 export default function App() {
+  const [messages, setMessages] = useState<MessageItem[]>([]);
+  const [wsStatus, setWsStatus] = useState<string>("connecting");
+  const wsRef = useRef<WebSocket | null>(null);
+
+  useEffect(() => {
+    let cancelled = false;
+
+    listMessages(new URLSearchParams({ limit: "30" }))
+      .then((result) => {
+        if (!cancelled) {
+          setMessages(result.data);
+        }
+      })
+      .catch((err) => {
+        if (!cancelled) {
+          console.error("Failed to load messages:", err);
+        }
+      });
+
+    const ws = connectDashboardSocket((event: DashboardEvent) => {
+      switch (event.type) {
+        case "message_created":
+          setMessages((prev) => [event.data, ...prev].slice(0, 200));
+          break;
+        case "message_analyzed":
+          setMessages((prev) =>
+            prev.map((m) => (m.id === event.data.id ? event.data : m)),
+          );
+          break;
+        case "message_updated":
+          setMessages((prev) =>
+            prev.map((m) => (m.id === event.data.id ? { ...m, ...event.data } : m)),
+          );
+          break;
+        case "message_deleted":
+          setMessages((prev) =>
+            prev.map((m) =>
+              m.id === event.data.id ? { ...m, type: "deleted" as const } : m,
+            ),
+          );
+          break;
+      }
+    });
+
+    wsRef.current = ws;
+
+    ws.addEventListener("open", () => setWsStatus("connected"));
+    ws.addEventListener("close", () => setWsStatus("disconnected"));
+    ws.addEventListener("error", () => setWsStatus("error"));
+
+    return () => {
+      cancelled = true;
+      ws.close();
+      wsRef.current = null;
+    };
+  }, []);
+
   return (
     <div className="app">
-      <h1>Discord Moderation Dashboard</h1>
-      <p>React/Vite scaffold - dashboard components coming soon</p>
+      <div className="sidebar">
+        <div className="sidebar-header">Moderation</div>
+        <div className="sidebar-placeholder">Channels placeholder</div>
+      </div>
+
+      <div className="main">
+        <div className="header">
+          <h1>Discord Moderation Dashboard</h1>
+          <span className="ws-status" data-status={wsStatus}>
+            {wsStatus}
+          </span>
+        </div>
+
+        <div className="content">
+          <div className="message-list">
+            {messages.length === 0 ? (
+              <p className="empty-state">No messages yet</p>
+            ) : (
+              messages.map((msg) => (
+                <div key={msg.id} className={`message-item type-${msg.type}`}>
+                  <img
+                    src={msg.avatar_url ?? "/default-avatar.png"}
+                    alt={msg.username}
+                    className="message-avatar"
+                    width={32}
+                    height={32}
+                  />
+                  <div className="message-body">
+                    <span className="message-username">{msg.username}</span>
+                    <span className="message-time">
+                      {new Date(msg.created_at).toLocaleString()}
+                    </span>
+                    {msg.type === "deleted" && (
+                      <span className="message-deleted">[deleted]</span>
+                    )}
+                    <p className="message-content">{msg.content}</p>
+                  </div>
+                </div>
+              ))
+            )}
+          </div>
+        </div>
+
+        <div className="review-panel">
+          <div className="review-placeholder">Review placeholder</div>
+        </div>
+      </div>
     </div>
   );
 }
diff --git a/frontend/src/api/client.ts b/frontend/src/api/client.ts
new file mode 100644
index 0000000..3b9d4dd
--- /dev/null
+++ b/frontend/src/api/client.ts
@@ -0,0 +1,101 @@
+export type AIStatus = "pending" | "clean" | "warn" | "flagged" | "error";
+
+export interface MessageRecord {
+  id: string;
+  guild_id: string;
+  channel_id: string;
+  thread_id: string | null;
+  user_id: string;
+  username: string;
+  avatar_url: string | null;
+  content: string;
+  edited_content: string | null;
+  created_at: number;
+  edited_at: number | null;
+  deleted_at: number | null;
+  type: "text" | "edited" | "deleted";
+  metadata: string | null;
+  ai_status?: AIStatus | null;
+  ai_moderation_flags?: string | null;
+  ai_moderation_score?: number | null;
+  ai_moderation_raw?: string | null;
+  ai_analysis?: string | null;
+  ai_analyzed_at?: number | null;
+  ai_error?: string | null;
+}
+
+export interface PageResult<T> {
+  data: T[];
+  nextCursor: string | null;
+}
+
+export interface DashboardMessage {
+  id: string;
+  channel_id: string;
+  user_id: string;
+  username: string;
+  avatar_url: string | null;
+  content: string;
+  created_at: number;
+  type: "text" | "image" | "voice";
+}
+
+export interface Guild {
+  id: string;
+  name: string;
+  icon: string | null;
+}
+
+class ApiError extends Error {
+  code: string;
+  statusCode: number;
+
+  constructor(code: string, message: string, statusCode: number) {
+    super(message);
+    this.name = "ApiError";
+    this.code = code;
+    this.statusCode = statusCode;
+  }
+}
+
+async function request<T>(path: string, init?: RequestInit): Promise<T> {
+  const res = await fetch(path, {
+    headers: { "Content-Type": "application/json" },
+    ...init,
+  });
+
+  if (!res.ok) {
+    let message = res.statusText;
+    let code = "REQUEST_FAILED";
+    try {
+      const body = (await res.json()) as { error?: string; message?: string };
+      if (body.message) message = body.message;
+      if (body.error) code = body.error;
+    } catch {
+      // ignore parse errors
+    }
+    throw new ApiError(code, message, res.status);
+  }
+
+  return res.json() as Promise<T>;
+}
+
+export async function listMessages(
+  params: URLSearchParams,
+): Promise<PageResult<MessageRecord>> {
+  return request<PageResult<MessageRecord>>(`/api/messages?${params}`);
+}
+
+export async function listReview(
+  params: URLSearchParams,
+): Promise<PageResult<MessageRecord>> {
+  return request<PageResult<MessageRecord>>(`/api/review?${params}`);
+}
+
+export async function reanalyzeMessage(id: string): Promise<void> {
+  await request<void>(`/api/messages/${id}/reanalyze`, { method: "POST" });
+}
+
+export async function getGuilds(): Promise<Guild[]> {
+  return request<Guild[]>("/api/guilds");
+}
diff --git a/frontend/src/styles.css b/frontend/src/styles.css
index 4a266bd..01bd8b3 100644
--- a/frontend/src/styles.css
+++ b/frontend/src/styles.css
@@ -1,30 +1,173 @@
 * {
+  box-sizing: border-box;
   margin: 0;
   padding: 0;
-  box-sizing: border-box;
 }
 
 body {
-  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "Roboto", "Oxygen",
-    "Ubuntu", "Cantarell", "Fira Sans", "Droid Sans", "Helvetica Neue",
-    sans-serif;
-  -webkit-font-smoothing: antialiased;
-  -moz-osx-font-smoothing: grayscale;
-  background-color: #1e1e1e;
-  color: #e0e0e0;
+  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
+  background: #1e1e2e;
+  color: #cdd6f4;
+  height: 100vh;
+  overflow: hidden;
+}
+
+#root {
+  height: 100%;
 }
 
 .app {
-  padding: 2rem;
-  max-width: 1200px;
-  margin: 0 auto;
+  display: flex;
+  height: 100vh;
 }
 
-h1 {
-  margin-bottom: 1rem;
-  color: #ffffff;
+.sidebar {
+  width: 220px;
+  background: #181825;
+  border-right: 1px solid #313244;
+  display: flex;
+  flex-direction: column;
+  flex-shrink: 0;
 }
 
-p {
-  color: #b0b0b0;
+.sidebar-header {
+  padding: 16px;
+  font-size: 14px;
+  font-weight: 700;
+  color: #cdd6f4;
+  border-bottom: 1px solid #313244;
 }
+
+.sidebar-placeholder {
+  padding: 16px;
+  font-size: 12px;
+  color: #6c7086;
+  flex: 1;
+}
+
+.main {
+  flex: 1;
+  display: flex;
+  flex-direction: column;
+  overflow: hidden;
+}
+
+.header {
+  display: flex;
+  align-items: center;
+  justify-content: space-between;
+  padding: 12px 20px;
+  border-bottom: 1px solid #313244;
+  background: #181825;
+  flex-shrink: 0;
+}
+
+.header h1 {
+  font-size: 16px;
+  font-weight: 600;
+  color: #cdd6f4;
+}
+
+.ws-status {
+  font-size: 11px;
+  padding: 3px 8px;
+  border-radius: 4px;
+  font-weight: 500;
+}
+
+.ws-status[data-status="connected"] {
+  background: #a6e3a1;
+  color: #1e1e2e;
+}
+
+.ws-status[data-status="disconnected"],
+.ws-status[data-status="error"] {
+  background: #f38ba8;
+  color: #1e1e2e;
+}
+
+.ws-status[data-status="connecting"] {
+  background: #f9e2af;
+  color: #1e1e2e;
+}
+
+.content {
+  flex: 1;
+  overflow-y: auto;
+  padding: 16px;
+}
+
+.message-list {
+  display: flex;
+  flex-direction: column;
+  gap: 8px;
+}
+
+.empty-state {
+  text-align: center;
+  color: #6c7086;
+  padding: 40px;
+}
+
+.message-item {
+  display: flex;
+  gap: 12px;
+  padding: 10px 12px;
+  background: #181825;
+  border-radius: 6px;
+  border: 1px solid #313244;
+}
+
+.message-item.type-deleted {
+  opacity: 0.6;
+}
+
+.message-avatar {
+  width: 32px;
+  height: 32px;
+  border-radius: 50%;
+  flex-shrink: 0;
+}
+
+.message-body {
+  flex: 1;
+  min-width: 0;
+}
+
+.message-username {
+  font-weight: 600;
+  color: #89b4fa;
+  margin-right: 8px;
+}
+
+.message-time {
+  font-size: 11px;
+  color: #6c7086;
+}
+
+.message-deleted {
+  font-size: 11px;
+  color: #f38ba8;
+  margin-left: 8px;
+  font-style: italic;
+}
+
+.message-content {
+  margin-top: 4px;
+  font-size: 13px;
+  color: #bac2de;
+  white-space: pre-wrap;
+  word-break: break-word;
+}
+
+.review-panel {
+  border-top: 1px solid #313244;
+  background: #181825;
+  flex-shrink: 0;
+}
+
+.review-placeholder {
+  padding: 16px;
+  font-size: 12px;
+  color: #6c7086;
+}
\ No newline at end of file
diff --git a/frontend/src/ws/client.ts b/frontend/src/ws/client.ts
new file mode 100644
index 0000000..aa44679
--- /dev/null
+++ b/frontend/src/ws/client.ts
@@ -0,0 +1,32 @@
+import type { MessageRecord } from "../api/client";
+
+export type DashboardEvent =
+  | { type: "message_created"; data: MessageRecord }
+  | { type: "message_updated"; data: Partial<MessageRecord> & { id: string } }
+  | { type: "message_deleted"; data: { id: string; deleted_at: number } }
+  | { type: "message_analyzed"; data: MessageRecord }
+  | { type: "analysis_queue_status"; data: unknown }
+  | { type: "ui_state"; state: unknown }
+  | { type: "user_state"; users: unknown[] };
+
+export function connectDashboardSocket(
+  onEvent: (event: DashboardEvent) => void,
+): WebSocket {
+  const protocol = window.location.protocol === "https:" ? "wss:" : "ws:";
+  const url = `${protocol}//${window.location.host}/ws`;
+  const ws = new WebSocket(url);
+
+  ws.addEventListener("message", (evt) => {
+    if (typeof evt.data === "string") {
+      try {
+        const event = JSON.parse(evt.data) as DashboardEvent;
+        onEvent(event);
+      } catch {
+        // ignore malformed JSON
+      }
+    }
+    // Binary frames (PCM audio) are ignored for now
+  });
+
+  return ws;
+}
\ No newline at end of file