diff --git a/Endpoints/ChatEndpoint.cs b/Endpoints/ChatEndpoint.cs
index eb54ded..0df4d8f 100644
--- a/Endpoints/ChatEndpoint.cs
+++ b/Endpoints/ChatEndpoint.cs
@@ -50,16 +50,27 @@ public static class ChatEndpoint
         res.Headers["Cache-Control"] = "no-cache";
         res.Headers["Connection"] = "keep-alive";
 
+        var sessionId = body.SessionId;
+        if (string.IsNullOrEmpty(sessionId))
+        {
+            res.StatusCode = 400;
+            await res.WriteAsJsonAsync(new { error = "sessionId required" });
+            return;
+        }
+
         var chainId = Guid.NewGuid().ToString("N");
 
-        // Chain zuerst anlegen (FK für messages)
         await db.CreateChain(new ChainRecord
         {
             ChainId = chainId,
+            SessionId = sessionId,
             Model = modelId,
             SystemPrompt = body.SystemPrompt
         });
 
+        // Session-Timestamp aktualisieren
+        await db.UpdateSessionTimestamp(sessionId);
+
         var messages = new List<object>();
         foreach (var msg in body.Messages)
             messages.Add(new { role = msg.Role, content = msg.Content });
diff --git a/Endpoints/HistoryEndpoint.cs b/Endpoints/HistoryEndpoint.cs
index 2eebd60..dcfd933 100644
--- a/Endpoints/HistoryEndpoint.cs
+++ b/Endpoints/HistoryEndpoint.cs
@@ -23,12 +23,14 @@ public static class HistoryEndpoint
     private static async Task HandleHistory(HttpContext ctx, DatabaseService db)
     {
         var sessionId = ctx.Request.Query["sessionId"].FirstOrDefault();
+        if (string.IsNullOrEmpty(sessionId))
+        {
+            ctx.Response.StatusCode = 400;
+            await ctx.Response.WriteAsJsonAsync(new { error = "sessionId required" });
+            return;
+        }
 
-        IEnumerable<ChainRecord> chains;
-        if (string.IsNullOrEmpty(sessionId) || sessionId == "null")
-            chains = await db.GetActiveChains();
-        else
-            chains = await db.GetSessionChains(sessionId);
+        var chains = await db.GetActiveChains(sessionId);
 
         var result = new List<object>();
         foreach (var chain in chains)
@@ -42,16 +44,30 @@ public static class HistoryEndpoint
 
     private static async Task HandlePoll(HttpContext ctx, DatabaseService db)
     {
+        var sessionId = ctx.Request.Query["sessionId"].FirstOrDefault();
         var afterStr = ctx.Request.Query["afterId"].FirstOrDefault();
         var afterId = long.TryParse(afterStr, out var a) ? a : 0;
 
-        var messages = await db.GetActiveMessagesAfterId(afterId);
+        if (string.IsNullOrEmpty(sessionId))
+        {
+            ctx.Response.StatusCode = 400;
+            return;
+        }
+
+        var messages = await db.GetActiveMessagesAfterId(sessionId, afterId);
         await ctx.Response.WriteAsJsonAsync(messages);
     }
 
     private static async Task HandleArchive(HttpContext ctx, DatabaseService db)
     {
-        var archive = await db.CreateArchive();
+        var sessionId = ctx.Request.Query["sessionId"].FirstOrDefault();
+        if (string.IsNullOrEmpty(sessionId))
+        {
+            ctx.Response.StatusCode = 400;
+            return;
+        }
+
+        var archive = await db.CreateArchive(sessionId);
         if (archive == null)
         {
             ctx.Response.StatusCode = 204;
@@ -62,7 +78,14 @@ public static class HistoryEndpoint
 
     private static async Task HandleListArchives(HttpContext ctx, DatabaseService db)
     {
-        var archives = await db.GetArchives();
+        var sessionId = ctx.Request.Query["sessionId"].FirstOrDefault();
+        if (string.IsNullOrEmpty(sessionId))
+        {
+            ctx.Response.StatusCode = 400;
+            return;
+        }
+
+        var archives = await db.GetArchives(sessionId);
         await ctx.Response.WriteAsJsonAsync(archives);
     }
 
diff --git a/Endpoints/SessionEndpoint.cs b/Endpoints/SessionEndpoint.cs
new file mode 100644
index 0000000..a807ec7
--- /dev/null
+++ b/Endpoints/SessionEndpoint.cs
@@ -0,0 +1,50 @@
+using System.Linq;
+using System.Text.Json;
+using System.Threading.Tasks;
+using Gott.Services;
+using Microsoft.AspNetCore.Builder;
+using Microsoft.AspNetCore.Http;
+using Microsoft.AspNetCore.Routing;
+
+namespace Gott.Endpoints;
+
+public static class SessionEndpoint
+{
+    public static void MapSessionEndpoints(this IEndpointRouteBuilder app)
+    {
+        app.MapGet("/api/sessions", HandleList);
+        app.MapPost("/api/sessions", HandleCreate);
+        app.MapPut("/api/sessions/{sessionId}", HandleUpdate);
+    }
+
+    private static async Task HandleList(HttpContext ctx, DatabaseService db)
+    {
+        var sessions = await db.GetSessions();
+        await ctx.Response.WriteAsJsonAsync(sessions);
+    }
+
+    private static async Task HandleCreate(HttpContext ctx, DatabaseService db)
+    {
+        var session = await db.CreateSession("Neue Session");
+        await ctx.Response.WriteAsJsonAsync(session);
+    }
+
+    private static async Task HandleUpdate(HttpContext ctx, DatabaseService db)
+    {
+        var sessionId = ctx.Request.RouteValues["sessionId"]?.ToString();
+        if (string.IsNullOrEmpty(sessionId))
+        {
+            ctx.Response.StatusCode = 400;
+            return;
+        }
+
+        var body = await JsonSerializer.DeserializeAsync<JsonElement>(ctx.Request.Body);
+        if (body.TryGetProperty("name", out var nameEl))
+        {
+            await db.UpdateSessionName(sessionId, nameEl.GetString());
+        }
+
+        var session = await db.GetSession(sessionId);
+        await ctx.Response.WriteAsJsonAsync(session);
+    }
+}
diff --git a/Models/ArchiveRecord.cs b/Models/ArchiveRecord.cs
index 02f00ce..2e66f1e 100644
--- a/Models/ArchiveRecord.cs
+++ b/Models/ArchiveRecord.cs
@@ -4,6 +4,7 @@ public class ArchiveRecord
 {
     public long Id { get; set; }
     public string ArchiveId { get; set; }
+    public string SessionId { get; set; }
     public string Name { get; set; }
     public int ChainCount { get; set; }
     public int MessageCount { get; set; }
diff --git a/Models/ChatModels.cs b/Models/ChatModels.cs
index 1319178..545147e 100644
--- a/Models/ChatModels.cs
+++ b/Models/ChatModels.cs
@@ -22,4 +22,7 @@ public class ChatRequest
 
     [JsonPropertyName("systemPrompt")]
     public string SystemPrompt { get; set; } = "";
+
+    [JsonPropertyName("sessionId")]
+    public string SessionId { get; set; } = "";
 }
diff --git a/Models/SessionRecord.cs b/Models/SessionRecord.cs
new file mode 100644
index 0000000..cdf2e68
--- /dev/null
+++ b/Models/SessionRecord.cs
@@ -0,0 +1,10 @@
+namespace Gott.Models;
+
+public class SessionRecord
+{
+    public long Id { get; set; }
+    public string SessionId { get; set; }
+    public string Name { get; set; }
+    public string CreatedAt { get; set; }
+    public string UpdatedAt { get; set; }
+}
diff --git a/Program.cs b/Program.cs
index 32029f7..2167ef2 100644
--- a/Program.cs
+++ b/Program.cs
@@ -21,5 +21,6 @@ app.UseStaticFiles();
 
 app.MapChatEndpoint();
 app.MapHistoryEndpoint();
+app.MapSessionEndpoints();
 
 app.Run("http://0.0.0.0:19000");
diff --git a/Services/DatabaseService.cs b/Services/DatabaseService.cs
index 853bebb..9abf314 100644
--- a/Services/DatabaseService.cs
+++ b/Services/DatabaseService.cs
@@ -31,9 +31,18 @@ public class DatabaseService
         Dapper.DefaultTypeMap.MatchNamesWithUnderscores = true;
 
         conn.Execute(@"
+            CREATE TABLE IF NOT EXISTS sessions (
+                id            INTEGER PRIMARY KEY AUTOINCREMENT,
+                session_id    TEXT NOT NULL UNIQUE,
+                name          TEXT,
+                created_at    TEXT NOT NULL,
+                updated_at    TEXT NOT NULL
+            );
+
             CREATE TABLE IF NOT EXISTS archives (
                 id            INTEGER PRIMARY KEY AUTOINCREMENT,
                 archive_id    TEXT NOT NULL UNIQUE,
+                session_id    TEXT NOT NULL,
                 name          TEXT,
                 chain_count   INTEGER NOT NULL DEFAULT 0,
                 message_count INTEGER NOT NULL DEFAULT 0,
@@ -75,24 +84,76 @@ public class DatabaseService
         ");
     }
 
+    // ── Sessions ──
+
+    public async Task<SessionRecord> CreateSession(string name = null)
+    {
+        using var conn = CreateConnection();
+        var now = DateTime.UtcNow.ToString("o");
+        var session = new SessionRecord
+        {
+            SessionId = Guid.NewGuid().ToString("N"),
+            Name = name,
+            CreatedAt = now,
+            UpdatedAt = now
+        };
+        await conn.ExecuteAsync(@"
+            INSERT INTO sessions (session_id, name, created_at, updated_at)
+            VALUES (@SessionId, @Name, @CreatedAt, @UpdatedAt)
+        ", session);
+        return session;
+    }
+
+    public async Task<IEnumerable<SessionRecord>> GetSessions()
+    {
+        using var conn = CreateConnection();
+        return await conn.QueryAsync<SessionRecord>(
+            "SELECT * FROM sessions ORDER BY updated_at DESC");
+    }
+
+    public async Task<SessionRecord> GetSession(string sessionId)
+    {
+        using var conn = CreateConnection();
+        return await conn.QuerySingleOrDefaultAsync<SessionRecord>(
+            "SELECT * FROM sessions WHERE session_id = @sessionId", new { sessionId });
+    }
+
+    public async Task UpdateSessionTimestamp(string sessionId)
+    {
+        using var conn = CreateConnection();
+        await conn.ExecuteAsync(
+            "UPDATE sessions SET updated_at = @now WHERE session_id = @sessionId",
+            new { sessionId, now = DateTime.UtcNow.ToString("o") });
+    }
+
+    public async Task UpdateSessionName(string sessionId, string name)
+    {
+        using var conn = CreateConnection();
+        await conn.ExecuteAsync(
+            "UPDATE sessions SET name = @name, updated_at = @now WHERE session_id = @sessionId",
+            new { sessionId, name, now = DateTime.UtcNow.ToString("o") });
+    }
+
     // ── Archives ──
 
-    public async Task<ArchiveRecord> CreateArchive(string name = null)
+    public async Task<ArchiveRecord> CreateArchive(string sessionId, string name = null)
     {
         using var conn = CreateConnection();
 
-        // Zähle aktive Chains und Messages
         var chainCount = await conn.ExecuteScalarAsync<int>(
-            "SELECT COUNT(*) FROM chains WHERE archive_id IS NULL");
+            "SELECT COUNT(*) FROM chains WHERE archive_id IS NULL AND session_id = @sessionId",
+            new { sessionId });
         if (chainCount == 0) return null;
 
         var messageCount = await conn.ExecuteScalarAsync<int>(@"
             SELECT COUNT(*) FROM messages
-            WHERE chain_id IN (SELECT chain_id FROM chains WHERE archive_id IS NULL)");
+            WHERE chain_id IN (SELECT chain_id FROM chains WHERE archive_id IS NULL AND session_id = @sessionId)",
+            new { sessionId });
 
         var archive = new ArchiveRecord
         {
             ArchiveId = Guid.NewGuid().ToString("N"),
+            SessionId = sessionId,
             Name = name,
             ChainCount = chainCount,
             MessageCount = messageCount,
@@ -100,23 +161,23 @@ public class DatabaseService
         };
 
         await conn.ExecuteAsync(@"
-            INSERT INTO archives (archive_id, name, chain_count, message_count, created_at)
-            VALUES (@ArchiveId, @Name, @ChainCount, @MessageCount, @CreatedAt)
+            INSERT INTO archives (archive_id, session_id, name, chain_count, message_count, created_at)
+            VALUES (@ArchiveId, @SessionId, @Name, @ChainCount, @MessageCount, @CreatedAt)
         ", archive);
 
-        // Alle aktiven Chains diesem Archiv zuweisen
         await conn.ExecuteAsync(
-            "UPDATE chains SET archive_id = @archiveId WHERE archive_id IS NULL",
-            new { archiveId = archive.ArchiveId });
+            "UPDATE chains SET archive_id = @archiveId WHERE archive_id IS NULL AND session_id = @sessionId",
+            new { archiveId = archive.ArchiveId, sessionId });
 
         return archive;
     }
 
-    public async Task<IEnumerable<ArchiveRecord>> GetArchives(int limit = 20)
+    public async Task<IEnumerable<ArchiveRecord>> GetArchives(string sessionId)
     {
         using var conn = CreateConnection();
         return await conn.QueryAsync<ArchiveRecord>(
-            "SELECT * FROM archives ORDER BY id DESC LIMIT @limit", new { limit });
+            "SELECT * FROM archives WHERE session_id = @sessionId ORDER BY id DESC",
+            new { sessionId });
     }
 
     public async Task<IEnumerable<ChainRecord>> GetArchiveChains(string archiveId)
@@ -161,14 +222,7 @@ public class DatabaseService
         );
     }
 
-    public async Task<IEnumerable<ChainRecord>> GetActiveChains()
-    {
-        using var conn = CreateConnection();
-        return await conn.QueryAsync<ChainRecord>(
-            "SELECT * FROM chains WHERE archive_id IS NULL ORDER BY id DESC");
-    }
-
-    public async Task<IEnumerable<ChainRecord>> GetSessionChains(string sessionId)
+    public async Task<IEnumerable<ChainRecord>> GetActiveChains(string sessionId)
     {
         using var conn = CreateConnection();
         return await conn.QueryAsync<ChainRecord>(
@@ -197,14 +251,14 @@ public class DatabaseService
         );
     }
 
-    public async Task<IEnumerable<MessageRecord>> GetActiveMessagesAfterId(long afterId, int limit = 200)
+    public async Task<IEnumerable<MessageRecord>> GetActiveMessagesAfterId(string sessionId, long afterId, int limit = 200)
     {
         using var conn = CreateConnection();
         return await conn.QueryAsync<MessageRecord>(@"
             SELECT m.* FROM messages m
             JOIN chains c ON m.chain_id = c.chain_id
-            WHERE m.id > @afterId AND c.archive_id IS NULL
+            WHERE m.id > @afterId AND c.archive_id IS NULL AND c.session_id = @sessionId
             ORDER BY m.id LIMIT @limit",
-            new { afterId, limit });
+            new { sessionId, afterId, limit });
     }
 }
diff --git a/wwwroot/css/style.css b/wwwroot/css/style.css
index 7aa35f0..2befe50 100644
--- a/wwwroot/css/style.css
+++ b/wwwroot/css/style.css
@@ -4,10 +4,16 @@ body {
   background: #222;
   color: #eee;
   display: flex;
-  flex-direction: column;
   height: 100vh;
 }
 
+main {
+  flex: 1;
+  display: flex;
+  flex-direction: column;
+  min-width: 0;
+}
+
 body, input, select, button, textarea {
   font-family: monospace;
   font-size: 1em;
@@ -28,6 +34,7 @@ button:hover, select:hover, input:hover, textarea:hover {
 
 button {
   cursor: pointer;
+  line-height: 1.25;
 }
 
 textarea {
@@ -46,6 +53,68 @@ textarea {
   cursor: pointer;
 }
 
+/* ── Sidebar ── */
+
+#sidebar {
+  width: 260px;
+  background: #1a1a1a;
+  border-right: 1px solid #444;
+  display: flex;
+  flex-direction: column;
+  flex-shrink: 0;
+  overflow: hidden;
+}
+
+.sidebar-header {
+  padding: 1em;
+  border-bottom: 1px solid #444;
+  display: flex;
+  align-items: center;
+  justify-content: space-between;
+}
+
+.sidebar-header h2 {
+  font-size: 1em;
+}
+
+#sessionList {
+  flex: 1;
+  overflow-y: auto;
+}
+
+.session-item {
+  padding: 1em;
+  cursor: pointer;
+  display: flex;
+  flex-direction: column;
+  border-left: 3px solid transparent;
+}
+
+.session-item:hover { background: #333; }
+
+.session-item.active {
+  background: #333;
+  border-left-color: #eee;
+}
+
+.session-name {
+  white-space: nowrap;
+  overflow: hidden;
+  text-overflow: ellipsis;
+  border: 1px solid transparent;
+}
+
+.session-date {
+  color: #888;
+}
+
+.session-rename {
+  background: #222;
+  border: 1px solid #888;
+  outline: none;
+  width: 100%;
+}
+
 /* ── Header ── */
 
 header {
@@ -79,7 +148,7 @@ header h1 {
   background: #111;
   border-bottom: 1px solid #333;
   flex-shrink: 0;
-  min-height: 2em;
+  min-height: 2.5em;
 }
 
 /* ── Chat ── */
diff --git a/wwwroot/index.html b/wwwroot/index.html
index 775a39c..514388d 100644
--- a/wwwroot/index.html
+++ b/wwwroot/index.html
@@ -8,30 +8,41 @@
 </head>
 <body>
 
-<header>
-  <h1>// gott</h1>
-  <select id="model">
-    <option value="sonnet">Sonnet 4.6</option>
-    <option value="opus">Opus 4.6</option>
-  </select>
-  <button class="clear-btn" id="clearBtn">Clear</button>
-  <div class="toggle">
-    <input type="checkbox" id="showSystem">
-    <label for="showSystem">System Prompt</label>
+<aside id="sidebar">
+  <div class="sidebar-header">
+    <h2>Sessions</h2>
+    <button id="newSessionBtn" title="Neue Session">+</button>
   </div>
-</header>
+  <div id="sessionList"></div>
+</aside>
 
-<textarea id="systemPrompt" placeholder="System Prompt (SOUL.md Inhalt etc.)"></textarea>
-<div class="meta-bar" id="meta"></div>
-<div id="chat"></div>
+<main>
+  <header>
+    <h1>// gott</h1>
+    <select id="model">
+      <option value="sonnet">Sonnet 4.6</option>
+      <option value="opus">Opus 4.6</option>
+    </select>
+    <button class="clear-btn" id="clearBtn">Archivieren</button>
+    <div class="toggle">
+      <input type="checkbox" id="showSystem">
+      <label for="showSystem">System Prompt</label>
+    </div>
+  </header>
 
-<div class="input-area">
-  <textarea id="input" placeholder="Nachricht eingeben... (Ctrl+Enter)" rows="2"></textarea>
-  <button id="send">Senden</button>
-</div>
+  <textarea id="systemPrompt" placeholder="System Prompt (SOUL.md Inhalt etc.)"></textarea>
+  <div class="meta-bar" id="meta"></div>
+  <div id="chat"></div>
+
+  <div class="input-area">
+    <textarea id="input" placeholder="Nachricht eingeben... (Ctrl+Enter)" rows="2"></textarea>
+    <button id="send">Senden</button>
+  </div>
+</main>
 
 <script src="js/ui.js"></script>
 <script src="js/api.js"></script>
+<script src="js/session.js"></script>
 <script src="js/chat.js"></script>
 <script src="js/history.js"></script>
 <script src="js/app.js"></script>
diff --git a/wwwroot/js/api.js b/wwwroot/js/api.js
index b1eba09..18bda82 100644
--- a/wwwroot/js/api.js
+++ b/wwwroot/js/api.js
@@ -1,31 +1,31 @@
 // ── API Calls ──
 
-async function apiChat(model, messages, systemPrompt) {
+async function apiChat(model, messages, systemPrompt, sessionId) {
   return fetch('/api/chat', {
     method: 'POST',
     headers: { 'Content-Type': 'application/json' },
-    body: JSON.stringify({ model, messages, systemPrompt })
+    body: JSON.stringify({ model, messages, systemPrompt, sessionId })
   });
 }
 
-async function apiHistory(sessionId = 'null') {
+async function apiHistory(sessionId) {
   const resp = await fetch(`/api/history?sessionId=${sessionId}`);
   return resp.json();
 }
 
-async function apiHistoryPoll(afterId) {
-  const resp = await fetch(`/api/history/poll?afterId=${afterId}`);
+async function apiHistoryPoll(sessionId, afterId) {
+  const resp = await fetch(`/api/history/poll?sessionId=${sessionId}&afterId=${afterId}`);
   return resp.json();
 }
 
-async function apiArchive() {
-  const resp = await fetch('/api/archive', { method: 'POST' });
+async function apiArchive(sessionId) {
+  const resp = await fetch(`/api/archive?sessionId=${sessionId}`, { method: 'POST' });
   if (resp.status === 204) return null;
   return resp.json();
 }
 
-async function apiListArchives() {
-  const resp = await fetch('/api/archives');
+async function apiListArchives(sessionId) {
+  const resp = await fetch(`/api/archives?sessionId=${sessionId}`);
   return resp.json();
 }
 
@@ -33,3 +33,24 @@ async function apiGetArchive(archiveId) {
   const resp = await fetch(`/api/archive/${archiveId}`);
   return resp.json();
 }
+
+// ── Session API ──
+
+async function apiGetSessions() {
+  const resp = await fetch('/api/sessions');
+  return resp.json();
+}
+
+async function apiCreateSession() {
+  const resp = await fetch('/api/sessions', { method: 'POST' });
+  return resp.json();
+}
+
+async function apiUpdateSession(sessionId, data) {
+  const resp = await fetch(`/api/sessions/${sessionId}`, {
+    method: 'PUT',
+    headers: { 'Content-Type': 'application/json' },
+    body: JSON.stringify(data)
+  });
+  return resp.json();
+}
diff --git a/wwwroot/js/app.js b/wwwroot/js/app.js
index 2694ffc..4f391b8 100644
--- a/wwwroot/js/app.js
+++ b/wwwroot/js/app.js
@@ -1,13 +1,18 @@
 // ── App Init ──
 
-document.addEventListener('DOMContentLoaded', () => {
+document.addEventListener('DOMContentLoaded', async () => {
+  // Session initialisieren (vor allem anderen)
+  await initSession();
+
   // System Prompt Toggle
   $('#showSystem').addEventListener('change', () => {
     $('#systemPrompt').classList.toggle('visible', $('#showSystem').checked);
   });
 
-  // Send Button
+  // Buttons
   $('#send').addEventListener('click', sendMessage);
+  $('#clearBtn').addEventListener('click', clearChat);
+  $('#newSessionBtn').addEventListener('click', createNewSession);
 
   // Ctrl+Enter
   $('#input').addEventListener('keydown', (e) => {
@@ -20,9 +25,6 @@ document.addEventListener('DOMContentLoaded', () => {
     this.style.height = Math.min(this.scrollHeight, 150) + 'px';
   });
 
-  // Clear Button
-  $('#clearBtn').addEventListener('click', clearChat);
-
   // History laden
-  loadHistory();
+  await loadHistory();
 });
diff --git a/wwwroot/js/chat.js b/wwwroot/js/chat.js
index c1f7456..8c48f3a 100644
--- a/wwwroot/js/chat.js
+++ b/wwwroot/js/chat.js
@@ -4,17 +4,16 @@ const messages = [];
 let isStreaming = false;
 
 async function clearChat() {
-  const archive = await apiArchive();
+  const archive = await apiArchive(getCurrentSessionId());
+  if (!archive) return;
+
   messages.length = 0;
   chatEl().innerHTML = '';
   lastKnownMessageId = 0;
+  loadedArchiveCount = 0;
 
-  if (archive) {
-    setMeta(`Archiviert: ${archive.chainCount} Chains, ${archive.messageCount} Messages`);
-    showArchiveLoadButton();
-  } else {
-    setMeta('');
-  }
+  setMeta(`Archiviert: ${archive.chainCount} Chains, ${archive.messageCount} Messages`);
+  showArchiveLoadButton();
 }
 
 // ── Send Message ──
@@ -40,7 +39,7 @@ async function sendMessage() {
   let currentToolBox = null;
 
   try {
-    const resp = await apiChat(model, messages, systemPrompt);
+    const resp = await apiChat(model, messages, systemPrompt, getCurrentSessionId());
     const reader = resp.body.getReader();
     const decoder = new TextDecoder();
     let buffer = '';
diff --git a/wwwroot/js/history.js b/wwwroot/js/history.js
index 6d0fffb..b63edd1 100644
--- a/wwwroot/js/history.js
+++ b/wwwroot/js/history.js
@@ -6,12 +6,13 @@ let loadedArchiveCount = 0;
 
 async function loadHistory() {
   try {
-    const archives = await apiListArchives();
+    const sid = getCurrentSessionId();
+    const archives = await apiListArchives(sid);
     if (archives.length > 0) {
       showArchiveLoadButton();
     }
 
-    const data = await apiHistory('null');
+    const data = await apiHistory(sid);
     data.reverse();
 
     for (const entry of data) {
@@ -82,7 +83,7 @@ function getOrCreateArchiveDivider() {
 
 async function loadLatestArchive() {
   try {
-    const archives = await apiListArchives();
+    const archives = await apiListArchives(getCurrentSessionId());
     if (archives.length <= loadedArchiveCount) return;
 
     const latest = archives[loadedArchiveCount];
@@ -163,7 +164,7 @@ async function pollHistory() {
   if (isStreaming) return;
 
   try {
-    const newMessages = await apiHistoryPoll(lastKnownMessageId);
+    const newMessages = await apiHistoryPoll(getCurrentSessionId(), lastKnownMessageId);
     if (newMessages.length > 0) {
       renderMessages(newMessages, true);
       scrollDown();
diff --git a/wwwroot/js/session.js b/wwwroot/js/session.js
new file mode 100644
index 0000000..e0f3135
--- /dev/null
+++ b/wwwroot/js/session.js
@@ -0,0 +1,108 @@
+// ── Session State ──
+
+let currentSessionId = null;
+
+function getCurrentSessionId() {
+  return currentSessionId;
+}
+
+async function initSession() {
+  // SessionId aus localStorage oder neue erstellen
+  const stored = localStorage.getItem('sessionId');
+  if (stored) {
+    currentSessionId = stored;
+  } else {
+    const session = await apiCreateSession();
+    currentSessionId = session.sessionId;
+    localStorage.setItem('sessionId', currentSessionId);
+  }
+
+  await refreshSessionList();
+}
+
+async function createNewSession() {
+  const session = await apiCreateSession();
+  currentSessionId = session.sessionId;
+  localStorage.setItem('sessionId', currentSessionId);
+
+  // Chat leeren und neu laden
+  messages.length = 0;
+  chatEl().innerHTML = '';
+  lastKnownMessageId = 0;
+  loadedArchiveCount = 0;
+  setMeta('');
+
+  await refreshSessionList();
+  await loadHistory();
+}
+
+async function switchSession(sessionId) {
+  if (sessionId === currentSessionId) return;
+
+  currentSessionId = sessionId;
+  localStorage.setItem('sessionId', currentSessionId);
+
+  // Chat leeren und Session laden
+  messages.length = 0;
+  chatEl().innerHTML = '';
+  lastKnownMessageId = 0;
+  loadedArchiveCount = 0;
+  setMeta('');
+
+  await refreshSessionList();
+  await loadHistory();
+}
+
+async function refreshSessionList() {
+  const sessions = await apiGetSessions();
+  const list = $('#sessionList');
+  list.innerHTML = '';
+
+  for (const s of sessions) {
+    const div = document.createElement('div');
+    div.className = 'session-item' + (s.sessionId === currentSessionId ? ' active' : '');
+    div.dataset.sessionId = s.sessionId;
+
+    const name = document.createElement('span');
+    name.className = 'session-name';
+    name.textContent = s.name || 'Unbenannt';
+    name.addEventListener('dblclick', () => renameSession(s.sessionId, name));
+
+    const date = document.createElement('span');
+    date.className = 'session-date';
+    date.textContent = new Date(s.updatedAt).toLocaleString('de-AT', {
+      day: '2-digit', month: '2-digit', hour: '2-digit', minute: '2-digit'
+    });
+
+    div.appendChild(name);
+    div.appendChild(date);
+    div.addEventListener('click', () => switchSession(s.sessionId));
+
+    list.appendChild(div);
+  }
+}
+
+async function renameSession(sessionId, nameEl) {
+  const input = document.createElement('input');
+  input.type = 'text';
+  input.className = 'session-rename';
+  input.value = nameEl.textContent;
+
+  nameEl.replaceWith(input);
+  input.focus();
+  input.select();
+
+  const save = async () => {
+    const newName = input.value.trim();
+    if (newName) {
+      await apiUpdateSession(sessionId, { name: newName });
+    }
+    await refreshSessionList();
+  };
+
+  input.addEventListener('blur', save);
+  input.addEventListener('keydown', (e) => {
+    if (e.key === 'Enter') input.blur();
+    if (e.key === 'Escape') { input.value = nameEl.textContent; input.blur(); }
+  });
+}