diff --git a/components/chat/chat-history-sidebar.tsx b/components/chat/chat-history-sidebar.tsx
index 095570f..3d45e8d 100644
--- a/components/chat/chat-history-sidebar.tsx
+++ b/components/chat/chat-history-sidebar.tsx
@@ -5,6 +5,7 @@ import {
   ArchiveIcon,
   ArchiveRestoreIcon,
   CheckIcon,
+  DownloadIcon,
   HistoryIcon,
   Loader2Icon,
   MessageSquarePlusIcon,
@@ -13,6 +14,7 @@ import {
   Trash2Icon,
   XIcon,
 } from "lucide-react";
+import { toast } from "sonner";
 
 import {
   AlertDialog,
@@ -25,6 +27,12 @@ import {
   AlertDialogTitle,
 } from "@/components/ui/alert-dialog";
 import { Button } from "@/components/ui/button";
+import {
+  DropdownMenu,
+  DropdownMenuContent,
+  DropdownMenuItem,
+  DropdownMenuTrigger,
+} from "@/components/ui/dropdown-menu";
 import { Input } from "@/components/ui/input";
 import { ScrollArea } from "@/components/ui/scroll-area";
 import {
@@ -35,7 +43,14 @@ import {
   SheetTitle,
 } from "@/components/ui/sheet";
 import { useIsMobile } from "@/hooks/use-mobile";
+import { useDebouncedValue } from "@/hooks/use-debounced-value";
 import { apiJson, apiJsonRequest } from "@/lib/api";
+import {
+  buildExportFilename,
+  conversationToJson,
+  conversationToMarkdown,
+  downloadTextFile,
+} from "@/lib/conversation-export";
 import { cn } from "@/lib/utils";
 
 type ConversationSummary = {
@@ -78,11 +93,20 @@ export function ChatHistorySidebar({
   const [bulkWorking, setBulkWorking] = useState(false);
   const renameInputRef = useRef<HTMLInputElement>(null);
 
-  const fetchConversations = useCallback(async () => {
+  // Busca server-side (título + conteúdo das mensagens) com debounce.
+  const debouncedSearch = useDebouncedValue(searchQuery.trim(), 300);
+  const isSearching = debouncedSearch.length >= 2;
+
+  const fetchConversations = useCallback(async (search: string) => {
     setLoading(true);
     try {
-      const query = showArchived ? "?archived=true" : "";
-      const data = await apiJson<{ conversations: ConversationSummary[] }>(`/conversations${query}`);
+      const params = new URLSearchParams();
+      if (showArchived) params.set("archived", "true");
+      if (search) params.set("q", search);
+      const qs = params.toString();
+      const data = await apiJson<{ conversations: ConversationSummary[] }>(
+        `/conversations${qs ? `?${qs}` : ""}`,
+      );
       setConversations(data.conversations);
       setSelectedIds(new Set());
     } catch {
@@ -93,8 +117,8 @@ export function ChatHistorySidebar({
   }, [showArchived]);
 
   useEffect(() => {
-    void fetchConversations();
-  }, [fetchConversations, refreshKey]);
+    void fetchConversations(isSearching ? debouncedSearch : "");
+  }, [fetchConversations, refreshKey, debouncedSearch, isSearching]);
 
   // Focus rename input when editing
   useEffect(() => {
@@ -216,12 +240,37 @@ export function ChatHistorySidebar({
     return title.replace(/^t[ií]tulo:\s*/i, "").trim() || "Nova conversa";
   }
 
+  async function handleExportConversation(
+    conv: ConversationSummary,
+    format: "json" | "md",
+  ) {
+    try {
+      const data = await apiJson<{
+        conversation: ConversationSummary;
+        messages: Array<{ content: string; createdAt: string; id: string; role: string }>;
+      }>(`/conversations/${conv.id}/messages`);
+
+      const filename = buildExportFilename(getConversationTitle(conv.title), format);
+      if (format === "json") {
+        downloadTextFile(filename, "application/json", conversationToJson(data.conversation, data.messages));
+        toast.success("Conversa exportada como JSON.");
+      } else {
+        downloadTextFile(filename, "text/markdown", conversationToMarkdown(data.conversation, data.messages));
+        toast.success("Conversa exportada como Markdown.");
+      }
+    } catch {
+      toast.error("Falha ao exportar a conversa.");
+    }
+  }
+
   // Filter + group conversations
   const filteredConversations = useMemo(() => {
+    // Busca ativa: o servidor já filtrou por título E conteúdo das mensagens.
+    if (isSearching) return conversations;
     if (!searchQuery.trim()) return conversations;
     const q = searchQuery.toLowerCase();
     return conversations.filter((c) => (c.title ?? "").toLowerCase().includes(q));
-  }, [conversations, searchQuery]);
+  }, [conversations, searchQuery, isSearching]);
 
   const selectedCount = selectedIds.size;
   const allVisibleSelected = filteredConversations.length > 0 && filteredConversations.every((c) => selectedIds.has(c.id));
@@ -301,6 +350,13 @@ export function ChatHistorySidebar({
             className="h-9 pl-7 text-base md:h-7 md:text-xs"
           />
         </div>
+        {isSearching && (
+          <p className="pt-1 text-[10px] text-muted-foreground" aria-live="polite">
+            {loading
+              ? "Buscando..."
+              : `${filteredConversations.length} conversa${filteredConversations.length === 1 ? "" : "s"} encontrada${filteredConversations.length === 1 ? "" : "s"} — título e conteúdo das mensagens`}
+          </p>
+        )}
       </div>
 
       {selectedCount > 0 && filteredConversations.length > 0 && (
@@ -452,6 +508,27 @@ export function ChatHistorySidebar({
                     </div>
                     {renamingId !== conv.id && (
                       <div className="flex shrink-0 gap-0.5 md:opacity-0 md:transition-opacity md:group-hover:opacity-100 md:group-focus-within:opacity-100">
+                        <DropdownMenu>
+                          <DropdownMenuTrigger asChild>
+                            <Button
+                              variant="ghost"
+                              size="icon-xs"
+                              className="size-8 md:size-6"
+                              onClick={(e) => e.stopPropagation()}
+                              title="Exportar conversa"
+                            >
+                              <DownloadIcon className="size-3" />
+                            </Button>
+                          </DropdownMenuTrigger>
+                          <DropdownMenuContent align="end" onClick={(e) => e.stopPropagation()}>
+                            <DropdownMenuItem onSelect={() => void handleExportConversation(conv, "json")}>
+                              Exportar (JSON)
+                            </DropdownMenuItem>
+                            <DropdownMenuItem onSelect={() => void handleExportConversation(conv, "md")}>
+                              Exportar (Markdown)
+                            </DropdownMenuItem>
+                          </DropdownMenuContent>
+                        </DropdownMenu>
                         <Button
                           variant="ghost"
                           size="icon-xs"
diff --git a/components/chat/chat-page.tsx b/components/chat/chat-page.tsx
index 88bd349..df3146b 100644
--- a/components/chat/chat-page.tsx
+++ b/components/chat/chat-page.tsx
@@ -47,6 +47,12 @@ import { useAppState } from "@/components/app-state-provider";
 import { ChatHistorySidebar } from "@/components/chat/chat-history-sidebar";
 import { SettingsDialog } from "@/components/chat/settings-dialog";
 import { MarkdownRenderer } from "@/components/markdown-renderer";
+import {
+  buildExportFilename,
+  conversationToJson,
+  conversationToMarkdown,
+  downloadTextFile,
+} from "@/lib/conversation-export";
 import { Alert, AlertDescription, AlertTitle } from "@/components/ui/alert";
 import { Badge } from "@/components/ui/badge";
 import { Button } from "@/components/ui/button";
@@ -1215,29 +1221,42 @@ export function ChatPage() {
 
 
   // Export conversation
+  function getExportableContent(m: ChatMessage): string {
+    return m.role === "user" && m.parts?.length
+      ? createMessageContentFallback(m.parts)
+      : m.content;
+  }
+
   function handleExportMarkdown() {
     if (messages.length === 0) return;
 
-    const mdContent = messages
-      .map((m) => {
-        const renderedContent =
-          m.role === "user" && m.parts?.length
-            ? createMessageContentFallback(m.parts)
-            : m.content;
-        return `## ${m.role === "user" ? "Você" : "Assistente"}\n\n${renderedContent}`;
-      })
-      .join("\n\n---\n\n");
-
-    const blob = new Blob([mdContent], { type: "text/markdown" });
-    const url = URL.createObjectURL(blob);
-    const a = document.createElement("a");
-    a.href = url;
-    a.download = `conversa-${new Date().toISOString().slice(0, 10)}.md`;
-    a.click();
-    URL.revokeObjectURL(url);
+    const mdContent = conversationToMarkdown(
+      null,
+      messages.map((m) => ({ content: getExportableContent(m), role: m.role })),
+    );
+
+    downloadTextFile(buildExportFilename(null, "md"), "text/markdown", mdContent);
     toast.success("Conversa exportada como Markdown.");
   }
 
+  function handleExportJson() {
+    if (messages.length === 0) return;
+
+    const jsonContent = conversationToJson(
+      null,
+      messages.map((m) => ({
+        content: getExportableContent(m),
+        createdAt: m.createdAt ?? null,
+        id: m.id,
+        modelLabel: m.modelLabel ?? null,
+        role: m.role,
+      })),
+    );
+
+    downloadTextFile(buildExportFilename(null, "json"), "application/json", jsonContent);
+    toast.success("Conversa exportada como JSON.");
+  }
+
   return (
     <div className="flex min-h-0 flex-1 flex-col md:flex-row">
       <div className="flex min-h-0 min-w-0 flex-1 flex-col">
@@ -1495,10 +1514,16 @@ export function ChatPage() {
               ) : null}
 
               {messages.length > 0 ? (
-                <DropdownMenuItem onSelect={handleExportMarkdown}>
-                  <DownloadIcon />
-                  Exportar (Markdown)
-                </DropdownMenuItem>
+                <>
+                  <DropdownMenuItem onSelect={handleExportMarkdown}>
+                    <DownloadIcon />
+                    Exportar (Markdown)
+                  </DropdownMenuItem>
+                  <DropdownMenuItem onSelect={handleExportJson}>
+                    <DownloadIcon />
+                    Exportar (JSON)
+                  </DropdownMenuItem>
+                </>
               ) : null}
             </DropdownMenuContent>
           </DropdownMenu>
diff --git a/hooks/use-debounced-value.ts b/hooks/use-debounced-value.ts
new file mode 100644
index 0000000..05fa8c9
--- /dev/null
+++ b/hooks/use-debounced-value.ts
@@ -0,0 +1,18 @@
+"use client";
+
+import { useEffect, useState } from "react";
+
+/**
+ * Returns a copy of `value` that only updates after `delayMs` of stability.
+ * Useful to avoid firing requests on every keystroke.
+ */
+export function useDebouncedValue<T>(value: T, delayMs: number): T {
+  const [debounced, setDebounced] = useState(value);
+
+  useEffect(() => {
+    const timer = setTimeout(() => setDebounced(value), delayMs);
+    return () => clearTimeout(timer);
+  }, [value, delayMs]);
+
+  return debounced;
+}
diff --git a/lib/conversation-export.test.ts b/lib/conversation-export.test.ts
new file mode 100644
index 0000000..c756206
--- /dev/null
+++ b/lib/conversation-export.test.ts
@@ -0,0 +1,131 @@
+import { afterEach, beforeEach, describe, expect, it, vi } from "vitest";
+
+import {
+  buildExportFilename,
+  conversationToJson,
+  conversationToMarkdown,
+} from "./conversation-export";
+
+describe("conversationToMarkdown", () => {
+  it("renderiza mensagens com rótulos de papel e separador", () => {
+    const md = conversationToMarkdown(null, [
+      { content: "olá", role: "user" },
+      { content: "oi! posso ajudar?", role: "assistant" },
+    ]);
+
+    expect(md).toBe("## Você\n\nolá\n\n---\n\n## Assistente\n\noi! posso ajudar?");
+  });
+
+  it("inclui cabeçalho com título quando a conversa possui um", () => {
+    const md = conversationToMarkdown(
+      { title: "Revisão de código" },
+      [{ content: "olá", role: "user" }],
+    );
+
+    expect(md).toBe("# Revisão de código\n\n## Você\n\nolá");
+  });
+
+  it("ignora título vazio ou só de espaços", () => {
+    expect(conversationToMarkdown({ title: "   " }, [{ content: "x", role: "user" }])).toBe(
+      "## Você\n\nx",
+    );
+  });
+
+  it("mapeia system e papéis desconhecidos de forma legível", () => {
+    const md = conversationToMarkdown(null, [
+      { content: "contexto", role: "system" },
+      { content: "dados", role: "tool" },
+    ]);
+
+    expect(md).toBe("## Sistema\n\ncontexto\n\n---\n\n## Tool\n\ndados");
+  });
+});
+
+describe("conversationToJson", () => {
+  beforeEach(() => {
+    vi.useFakeTimers();
+    vi.setSystemTime(new Date("2026-08-17T12:00:00.000Z"));
+  });
+
+  afterEach(() => {
+    vi.useRealTimers();
+  });
+
+  it("serializa metadados, timestamp de exportação e mensagens", () => {
+    const json = JSON.parse(
+      conversationToJson(
+        {
+          createdAt: "2026-08-01T10:00:00.000Z",
+          id: "conv-1",
+          modelId: "llama3.2",
+          providerId: "ollama",
+          title: "Teste",
+          updatedAt: "2026-08-02T10:00:00.000Z",
+        },
+        [
+          {
+            content: "olá",
+            createdAt: "2026-08-01T10:01:00.000Z",
+            id: "msg-1",
+            role: "user",
+          },
+        ],
+      ),
+    );
+
+    expect(json.exportedAt).toBe("2026-08-17T12:00:00.000Z");
+    expect(json.conversation).toEqual({
+      createdAt: "2026-08-01T10:00:00.000Z",
+      id: "conv-1",
+      modelId: "llama3.2",
+      providerId: "ollama",
+      title: "Teste",
+      updatedAt: "2026-08-02T10:00:00.000Z",
+    });
+    expect(json.messages).toEqual([
+      {
+        content: "olá",
+        createdAt: "2026-08-01T10:01:00.000Z",
+        id: "msg-1",
+        modelLabel: null,
+        role: "user",
+      },
+    ]);
+  });
+
+  it("usa null para metadados ausentes", () => {
+    const json = JSON.parse(conversationToJson(null, [{ content: "x", role: "user" }]));
+
+    expect(json.conversation).toEqual({
+      createdAt: null,
+      id: null,
+      modelId: null,
+      providerId: null,
+      title: null,
+      updatedAt: null,
+    });
+    expect(json.messages[0].id).toBeNull();
+  });
+});
+
+describe("buildExportFilename", () => {
+  it("normaliza título com acentos, espaços e maiúsculas", () => {
+    expect(buildExportFilename("Revisão de Código — API", "md")).toBe("revisao-de-codigo-api.md");
+  });
+
+  it("remove prefixo título: herdado da geração automática", () => {
+    expect(buildExportFilename("título: Integração com OpenAI", "json")).toBe(
+      "integracao-com-openai.json",
+    );
+  });
+
+  it("cai para o fallback datado quando não há título útil", () => {
+    vi.useFakeTimers();
+    vi.setSystemTime(new Date("2026-08-17T12:00:00.000Z"));
+
+    expect(buildExportFilename(null, "md")).toBe("conversa-2026-08-17.md");
+    expect(buildExportFilename("---", "json")).toBe("conversa-2026-08-17.json");
+
+    vi.useRealTimers();
+  });
+});
diff --git a/lib/conversation-export.ts b/lib/conversation-export.ts
new file mode 100644
index 0000000..6c40260
--- /dev/null
+++ b/lib/conversation-export.ts
@@ -0,0 +1,120 @@
+/**
+ * Helpers para exportar conversas em JSON e Markdown (issues #175/#176).
+ * Puramente client-side: sem dependência de DOM exceto `downloadTextFile`.
+ */
+
+export type ExportableConversationMeta = {
+  createdAt?: string | Date | null;
+  id?: string | null;
+  modelId?: string | null;
+  providerId?: string | null;
+  title?: string | null;
+  updatedAt?: string | Date | null;
+};
+
+export type MarkdownExportMessage = {
+  content: string;
+  role: string;
+};
+
+export type JsonExportMessage = {
+  content: string;
+  createdAt?: string | Date | null;
+  id?: string | null;
+  modelLabel?: string | null;
+  role: string;
+};
+
+function roleLabel(role: string): string {
+  if (role === "user") return "Você";
+  if (role === "assistant") return "Assistente";
+  if (role === "system") return "Sistema";
+  return role.charAt(0).toUpperCase() + role.slice(1);
+}
+
+/**
+ * Renderiza a conversa em Markdown legível. Quando `conversation` tem título,
+ * o documento começa com `# <título>`; com `conversation` nulo (ex.: exportação
+ * da conversa ativa sem metadados) o formato é idêntico ao histórico do chat.
+ */
+export function conversationToMarkdown(
+  conversation: ExportableConversationMeta | null,
+  messages: MarkdownExportMessage[],
+): string {
+  const body = messages
+    .map((m) => `## ${roleLabel(m.role)}\n\n${m.content}`)
+    .join("\n\n---\n\n");
+
+  const title = conversation?.title?.trim();
+  if (!title) return body;
+
+  return `# ${title}\n\n${body}`;
+}
+
+/**
+ * Serializa a conversa completa (metadados + mensagens + timestamps) em JSON.
+ */
+export function conversationToJson(
+  conversation: ExportableConversationMeta | null,
+  messages: JsonExportMessage[],
+): string {
+  return JSON.stringify(
+    {
+      exportedAt: new Date().toISOString(),
+      conversation: {
+        createdAt: conversation?.createdAt ?? null,
+        id: conversation?.id ?? null,
+        modelId: conversation?.modelId ?? null,
+        providerId: conversation?.providerId ?? null,
+        title: conversation?.title ?? null,
+        updatedAt: conversation?.updatedAt ?? null,
+      },
+      messages: messages.map((m) => ({
+        content: m.content,
+        createdAt: m.createdAt ?? null,
+        id: m.id ?? null,
+        modelLabel: m.modelLabel ?? null,
+        role: m.role,
+      })),
+    },
+    null,
+    2,
+  );
+}
+
+/**
+ * Gera nome de arquivo seguro a partir do título da conversa.
+ * Sem título (ou título irrelevante após normalização), cai para
+ * `conversa-YYYY-MM-DD`, igual ao comportamento histórico do chat.
+ */
+export function buildExportFilename(
+  title: string | null | undefined,
+  extension: "json" | "md",
+): string {
+  const fallback = `conversa-${new Date().toISOString().slice(0, 10)}`;
+
+  const slug = (title ?? "")
+    .normalize("NFD")
+    .replace(/[\u0300-\u036f]/g, "")
+    .toLowerCase()
+    .replace(/^t[ií]tulo:\s*/i, "")
+    .replace(/[^a-z0-9]+/g, "-")
+    .replace(/^-+|-+$/g, "")
+    .slice(0, 60)
+    .replace(/-+$/g, "");
+
+  return `${slug || fallback}.${extension}`;
+}
+
+/**
+ * Dispara o download de um arquivo de texto no navegador (padrão Blob + anchor).
+ */
+export function downloadTextFile(filename: string, mimeType: string, content: string): void {
+  const blob = new Blob([content], { type: mimeType });
+  const url = URL.createObjectURL(blob);
+  const anchor = document.createElement("a");
+  anchor.href = url;
+  anchor.download = filename;
+  anchor.click();
+  URL.revokeObjectURL(url);
+}
diff --git a/server/routes/conversations.ts b/server/routes/conversations.ts
index c0ea439..be36c68 100644
--- a/server/routes/conversations.ts
+++ b/server/routes/conversations.ts
@@ -209,14 +209,24 @@ async function persistMessages(conversationId: string, messages: CreateMessageIn
 }
 
 // GET /conversations — lista conversas do usuário
+// `q` (opcional) busca por título da conversa E conteúdo das mensagens.
 app.get("/", async (c) => {
   const userId = requireAuth(c);
   if (typeof userId !== "string") return userId;
 
   const archived = c.req.query("archived") === "true";
+  const q = c.req.query("q")?.trim() ?? "";
+
+  const where: Prisma.ConversationWhereInput = { userId, archived };
+  if (q) {
+    where.OR = [
+      { title: { contains: q, mode: "insensitive" } },
+      { messages: { some: { content: { contains: q, mode: "insensitive" } } } },
+    ];
+  }
 
   const conversations = await prisma.conversation.findMany({
-    where: { userId, archived },
+    where,
     select: {
       id: true,
       title: true,