diff --git a/backend/package.json b/backend/package.json
index 9fd0ab7..2770440 100644
--- a/backend/package.json
+++ b/backend/package.json
@@ -8,6 +8,7 @@
     "dev": "tsx watch src/index.ts",
     "build": "tsc -p tsconfig.json",
     "start": "node dist/index.js",
+    "test": "node --import tsx --test test/*.test.ts",
     "typecheck": "tsc -p tsconfig.json --noEmit"
   },
   "dependencies": {
diff --git a/backend/src/databaseExport.ts b/backend/src/databaseExport.ts
new file mode 100644
index 0000000..a27eca3
--- /dev/null
+++ b/backend/src/databaseExport.ts
@@ -0,0 +1,364 @@
+type QueryResult<T> = {
+  rows: T[];
+  rowCount: number | null;
+};
+
+export type QueryExecutor = {
+  query<T extends Record<string, unknown> = Record<string, unknown>>(text: string, params?: unknown[]): Promise<QueryResult<T>>;
+};
+
+export const databaseExportTables = [
+  "users",
+  "auth_sessions",
+  "app_settings",
+  "user_preferences",
+  "organizations",
+  "tickets",
+  "projects",
+  "project_teamspace_entries",
+  "hidden_user_projects",
+  "ticket_todos",
+  "recurring_billings",
+  "recurring_billing_slots",
+  "recurring_billing_exceptions",
+  "sessions",
+  "ticket_month_closures",
+  "month_closures",
+  "ticket_day_closures",
+  "day_closures",
+  "ticket_day_billings",
+  "ticket_day_billing_acknowledgements"
+] as const;
+
+type ColumnInfo = {
+  columnName: string;
+  dataType: string;
+  udtName: string;
+  ordinalPosition: number;
+  isNullable: "YES" | "NO";
+};
+
+const jsonDataTypes = new Set(["json", "jsonb"]);
+const insertBatchSize = 500;
+
+export function quoteIdentifier(value: string) {
+  return `"${value.replace(/"/g, '""')}"`;
+}
+
+function quoteSqlString(value: string) {
+  return `'${value.replace(/'/g, "''")}'`;
+}
+
+function isJsonColumn(column?: Pick<ColumnInfo, "dataType" | "udtName">) {
+  return Boolean(column && (jsonDataTypes.has(column.dataType) || jsonDataTypes.has(column.udtName)));
+}
+
+function jsonValueForSql(value: unknown) {
+  if (value instanceof Date) {
+    return JSON.stringify(value.toISOString());
+  }
+
+  const json = JSON.stringify(value);
+  return json === undefined ? "null" : json;
+}
+
+export function sqlLiteral(value: unknown, column?: Pick<ColumnInfo, "dataType" | "udtName">): string {
+  if (value === null || value === undefined) {
+    return "NULL";
+  }
+
+  if (Buffer.isBuffer(value)) {
+    return `decode('${value.toString("hex")}', 'hex')`;
+  }
+
+  if (isJsonColumn(column)) {
+    return quoteSqlString(jsonValueForSql(value));
+  }
+
+  if (value instanceof Date) {
+    return quoteSqlString(value.toISOString());
+  }
+
+  if (typeof value === "boolean") {
+    return value ? "TRUE" : "FALSE";
+  }
+
+  if (typeof value === "number") {
+    if (!Number.isFinite(value)) {
+      throw new Error("Cannot export non-finite number");
+    }
+
+    return String(value);
+  }
+
+  if (typeof value === "bigint") {
+    return String(value);
+  }
+
+  if (typeof value === "object") {
+    return quoteSqlString(jsonValueForSql(value));
+  }
+
+  return quoteSqlString(String(value));
+}
+
+function chunk<T>(items: T[], size: number) {
+  const chunks: T[][] = [];
+
+  for (let index = 0; index < items.length; index += size) {
+    chunks.push(items.slice(index, index + size));
+  }
+
+  return chunks;
+}
+
+async function tableColumns(client: QueryExecutor, table: string) {
+  const result = await client.query<ColumnInfo>(
+    `
+      SELECT
+        column_name AS "columnName",
+        data_type AS "dataType",
+        udt_name AS "udtName",
+        ordinal_position::int AS "ordinalPosition",
+        is_nullable AS "isNullable"
+      FROM information_schema.columns
+      WHERE table_schema = 'public'
+        AND table_name = $1
+      ORDER BY ordinal_position ASC;
+    `,
+    [table]
+  );
+
+  return result.rows;
+}
+
+function orderByClause(columns: ColumnInfo[]) {
+  if (columns.some((column) => column.columnName === "id")) {
+    return ` ORDER BY ${quoteIdentifier("id")}`;
+  }
+
+  const orderableColumns = columns.filter((column) => !isJsonColumn(column)).map((column) => quoteIdentifier(column.columnName));
+  return orderableColumns.length > 0 ? ` ORDER BY ${orderableColumns.join(", ")}` : "";
+}
+
+async function sequenceNameForIdColumn(client: QueryExecutor, table: string, columns: ColumnInfo[]) {
+  if (!columns.some((column) => column.columnName === "id")) {
+    return null;
+  }
+
+  const result = await client.query<{ sequenceName: string | null }>(
+    "SELECT pg_get_serial_sequence($1, 'id') AS \"sequenceName\";",
+    [`public.${table}`]
+  );
+
+  return result.rows[0]?.sequenceName ?? null;
+}
+
+export function sequenceSetvalSql(table: string, sequenceName: string) {
+  const quotedTable = quoteIdentifier(table);
+
+  return `SELECT setval(${quoteSqlString(sequenceName)}, COALESCE((SELECT MAX("id") FROM ${quotedTable}), 1), COALESCE((SELECT MAX("id") FROM ${quotedTable}), 0) > 0);`;
+}
+
+export function nextSequenceIdAfterRestore(maxId: number | null | undefined) {
+  return maxId && maxId > 0 ? maxId + 1 : 1;
+}
+
+export async function exportTableSql(client: QueryExecutor, table: string) {
+  const columns = await tableColumns(client, table);
+
+  if (columns.length === 0) {
+    return [`-- Tabelle ${table} existiert nicht im aktuellen Schema.`];
+  }
+
+  const columnNames = columns.map((column) => column.columnName);
+  const quotedColumns = columnNames.map(quoteIdentifier);
+  const rowsResult = await client.query<Record<string, unknown>>(
+    `
+      SELECT ${quotedColumns.join(", ")}
+      FROM ${quoteIdentifier(table)}${orderByClause(columns)};
+    `
+  );
+
+  const lines = [`-- ${table}: ${rowsResult.rows.length} Datensatz/Datensätze`, `-- columns ${table}: ${columnNames.join(",")}`];
+
+  for (const rows of chunk(rowsResult.rows, insertBatchSize)) {
+    if (rows.length === 0) {
+      continue;
+    }
+
+    lines.push(
+      [
+        `INSERT INTO ${quoteIdentifier(table)} (${quotedColumns.join(", ")}) VALUES`,
+        rows
+          .map((row) => `  (${columns.map((column) => sqlLiteral(row[column.columnName], column)).join(", ")})`)
+          .join(",\n") + ";"
+      ].join("\n")
+    );
+  }
+
+  const sequenceName = await sequenceNameForIdColumn(client, table, columns);
+
+  if (sequenceName) {
+    lines.push(sequenceSetvalSql(table, sequenceName));
+  }
+
+  return lines;
+}
+
+export async function currentTableColumns(client: QueryExecutor) {
+  const result = await client.query<{ table_name: string; column_name: string }>(
+    `
+      SELECT table_name, column_name
+      FROM information_schema.columns
+      WHERE table_schema = 'public'
+        AND table_name = ANY($1::text[])
+      ORDER BY table_name, ordinal_position ASC;
+    `,
+    [[...databaseExportTables]]
+  );
+  const columns = new Map<string, string[]>();
+
+  for (const row of result.rows) {
+    columns.set(row.table_name, [...(columns.get(row.table_name) ?? []), row.column_name]);
+  }
+
+  return columns;
+}
+
+export function restoreSqlText(sql: string) {
+  const trimmed = sql.replace(/^\uFEFF/, "").trim();
+
+  if (!trimmed.includes("TicketTracker Datenbankexport")) {
+    throw new Error("Nur TicketTracker-SQL-Backups können eingespielt werden");
+  }
+
+  return trimmed
+    .replace(/^\s*BEGIN\s*;\s*$/gim, "")
+    .replace(/^\s*SET\s+LOCAL\s+(?:lock_timeout|statement_timeout)\s*=\s*'[^']*'\s*;\s*$/gim, "")
+    .replace(/^\s*COMMIT\s*;\s*$/gim, "")
+    .replace(/TRUNCATE\s+TABLE[\s\S]*?;\s*/i, "")
+    .trim();
+}
+
+function parseDumpColumnList(value: string) {
+  const quoted = [...value.matchAll(/"((?:[^"]|"")+)"/g)].map((match) => match[1].replace(/""/g, '"'));
+
+  if (quoted.length > 0) {
+    return quoted;
+  }
+
+  return value
+    .split(",")
+    .map((column) => column.trim().replace(/^"|"$/g, ""))
+    .filter(Boolean);
+}
+
+export type RestoreValidationResult = {
+  valid: boolean;
+  checkedTables: number;
+  issues: string[];
+};
+
+export async function validateTicketTrackerBackup(client: QueryExecutor, sql: string): Promise<RestoreValidationResult> {
+  const issues: string[] = [];
+  let body = "";
+
+  try {
+    body = restoreSqlText(sql);
+  } catch (error) {
+    return {
+      valid: false,
+      checkedTables: 0,
+      issues: [error instanceof Error ? error.message : "Backup-Datei konnte nicht gelesen werden"]
+    };
+  }
+
+  const dumpColumns = new Map<string, Set<string>>();
+
+  for (const match of sql.matchAll(/^--\s*columns\s+([a-z_][a-z0-9_]*):\s*(.+)$/gim)) {
+    dumpColumns.set(match[1], new Set(parseDumpColumnList(match[2])));
+  }
+
+  for (const match of body.matchAll(/INSERT\s+INTO\s+"?([a-z_][a-z0-9_]*)"?\s*\(([^)]+)\)\s*VALUES/gi)) {
+    const table = match[1];
+    const columns = dumpColumns.get(table) ?? new Set<string>();
+
+    for (const column of parseDumpColumnList(match[2])) {
+      columns.add(column);
+    }
+
+    dumpColumns.set(table, columns);
+  }
+
+  for (const table of dumpColumns.keys()) {
+    if (!(databaseExportTables as readonly string[]).includes(table)) {
+      issues.push(`Dump enthält unbekannte Tabelle "${table}".`);
+    }
+  }
+
+  const dbColumns = await currentTableColumns(client);
+
+  for (const table of databaseExportTables) {
+    const currentColumns = dbColumns.get(table) ?? [];
+    const backupColumns = dumpColumns.get(table);
+
+    if (currentColumns.length === 0) {
+      issues.push(`Aktuelle Datenbank enthält Tabelle "${table}" nicht.`);
+      continue;
+    }
+
+    if (!backupColumns) {
+      issues.push(`Dump enthält keine Strukturinformationen für Tabelle "${table}". Bitte ein aktuelles TicketTracker-Backup verwenden.`);
+      continue;
+    }
+
+    const missingInDump = currentColumns.filter((column) => !backupColumns.has(column));
+    const extraInDump = [...backupColumns].filter((column) => !currentColumns.includes(column));
+
+    if (missingInDump.length > 0) {
+      issues.push(`Dump passt nicht zu Tabelle "${table}": Feld(er) fehlen: ${missingInDump.join(", ")}.`);
+    }
+
+    if (extraInDump.length > 0) {
+      issues.push(`Dump passt nicht zu Tabelle "${table}": unbekannte Feld(er): ${extraInDump.join(", ")}.`);
+    }
+  }
+
+  return {
+    valid: issues.length === 0,
+    checkedTables: databaseExportTables.length,
+    issues
+  };
+}
+
+export async function exportDatabaseSql(client: QueryExecutor) {
+  const lines = [
+    "-- TicketTracker Datenbankexport",
+    `-- Erstellt: ${new Date().toISOString()}`,
+    "--",
+    "-- Restore:",
+    "-- 1. Frische PostgreSQL-Datenbank erstellen.",
+    "-- 2. TicketTracker-Migrationen ausführen.",
+    "-- 3. TicketTracker-Backend stoppen.",
+    "-- 4. Diese Datei einspielen:",
+    "--    psql -v ON_ERROR_STOP=1 -d DATABASE -f backup.sql",
+    "-- 5. TicketTracker-Backend wieder starten.",
+    "--",
+    "-- Der Restore läuft atomar in einer Transaktion.",
+    "-- ACHTUNG: TRUNCATE benötigt exklusive PostgreSQL-Locks auf den betroffenen Tabellen.",
+    "-- Für den Restore sollte das TicketTracker-Backend gestoppt werden.",
+    "",
+    "BEGIN;",
+    "SET LOCAL lock_timeout = '10s';",
+    "SET LOCAL statement_timeout = '15min';",
+    `TRUNCATE TABLE ${[...databaseExportTables].reverse().map(quoteIdentifier).join(", ")} RESTART IDENTITY CASCADE;`
+  ];
+
+  for (const table of databaseExportTables) {
+    lines.push("", ...(await exportTableSql(client, table)));
+  }
+
+  lines.push("", "COMMIT;", "");
+  return lines.join("\n");
+}
diff --git a/backend/src/index.ts b/backend/src/index.ts
index d24350f..094b4ae 100644
--- a/backend/src/index.ts
+++ b/backend/src/index.ts
@@ -8,6 +8,13 @@ import type pg from "pg";
 import { migrate } from "./migrations.js";
 import { pool, query, withTransaction } from "./db.js";
 import { clearAuthSession, createAuthSession, currentUser, hashPassword, requireAdmin, requireAuth, requireUser, verifyPassword } from "./auth.js";
+import {
+  databaseExportTables as backupTables,
+  exportDatabaseSql,
+  quoteIdentifier as quoteBackupIdentifier,
+  restoreSqlText as backupRestoreSqlText,
+  validateTicketTrackerBackup as validateBackupSql
+} from "./databaseExport.js";
 import {
   badRequest,
   parseDay,
@@ -33,11 +40,78 @@ app.use(cors());
 app.use(express.text({ type: ["text/plain", "text/sql"], limit: requestBodyLimit }));
 app.use(express.json({ limit: requestBodyLimit }));
 
+type RestoreDebugState = {
+  id: string;
+  startedAt: string;
+  finishedAt: string | null;
+  phase: string;
+  ok: boolean | null;
+  error: string | null;
+  sqlBytes: number;
+  bodyBytes: number | null;
+  checkedTables: number | null;
+  issueCount: number | null;
+  adminCount: number | null;
+};
+
+let lastRestoreDebugState: RestoreDebugState | null = null;
+
+function logDebug(event: string, details: Record<string, unknown> = {}) {
+  console.info(`[tickettracker:${event}] ${JSON.stringify(details)}`);
+}
+
+function updateRestoreDebug(id: string, update: Partial<RestoreDebugState>) {
+  if (!lastRestoreDebugState || lastRestoreDebugState.id !== id) {
+    return;
+  }
+
+  lastRestoreDebugState = {
+    ...lastRestoreDebugState,
+    ...update
+  };
+  logDebug("restore", {
+    id,
+    phase: lastRestoreDebugState.phase,
+    ok: lastRestoreDebugState.ok,
+    sqlBytes: lastRestoreDebugState.sqlBytes,
+    bodyBytes: lastRestoreDebugState.bodyBytes,
+    checkedTables: lastRestoreDebugState.checkedTables,
+    issueCount: lastRestoreDebugState.issueCount,
+    adminCount: lastRestoreDebugState.adminCount,
+    error: lastRestoreDebugState.error
+  });
+}
+
 app.get("/api/health", async (_req, res) => {
   await query("SELECT 1");
   res.json({ ok: true });
 });
 
+app.get("/api/debug/status", async (_req, res) => {
+  const startedAt = Date.now();
+  const tableCounts: Record<string, number> = {};
+  const adminResult = await query<{ count: string }>("SELECT COUNT(*) AS count FROM users WHERE role = 'admin';");
+
+  for (const table of backupTables) {
+    const countResult = await query<{ count: string }>(`SELECT COUNT(*) AS count FROM ${quoteBackupIdentifier(table)};`);
+    tableCounts[table] = Number(countResult.rows[0]?.count ?? 0);
+  }
+
+  res.json({
+    ok: true,
+    timestamp: new Date().toISOString(),
+    uptimeSeconds: Math.round(process.uptime()),
+    database: {
+      ok: true,
+      adminCount: Number(adminResult.rows[0]?.count ?? 0),
+      tableCounts
+    },
+    restore: lastRestoreDebugState,
+    requestBodyLimit,
+    durationMs: Date.now() - startedAt
+  });
+});
+
 type PeriodConfig = {
   type: "month" | "day";
   tablePrefix: "month" | "day";
@@ -3416,7 +3490,7 @@ app.post("/api/setup/restore/validate", async (req, res) => {
   }
 
   const sql = restoreSqlFromRequestBody(req.body);
-  res.json(await validateTicketTrackerBackup(sql));
+  res.json(await validateBackupSql({ query }, sql));
 });
 
 app.post("/api/auth/login", async (req, res) => {
@@ -3914,265 +3988,100 @@ app.post("/api/admin/zammad/organizations/sync", requireAdmin, async (req, res)
   });
 });
 
-const databaseExportTables = [
-  "users",
-  "auth_sessions",
-  "app_settings",
-  "user_preferences",
-  "organizations",
-  "tickets",
-  "projects",
-  "project_teamspace_entries",
-  "ticket_todos",
-  "recurring_billings",
-  "recurring_billing_slots",
-  "recurring_billing_exceptions",
-  "sessions",
-  "ticket_month_closures",
-  "month_closures",
-  "ticket_day_closures",
-  "day_closures",
-  "ticket_day_billings",
-  "ticket_day_billing_acknowledgements"
-] as const;
-
-type RestoreValidationResult = {
-  valid: boolean;
-  checkedTables: number;
-  issues: string[];
-};
-
-function quoteIdentifier(value: string) {
-  return `"${value.replace(/"/g, '""')}"`;
-}
-
-function quoteLiteral(value: unknown) {
-  if (value === null || value === undefined) {
-    return "NULL";
-  }
-
-  if (value instanceof Date) {
-    return `'${value.toISOString().replace(/'/g, "''")}'`;
-  }
-
-  if (Buffer.isBuffer(value)) {
-    return `decode('${value.toString("hex")}', 'hex')`;
-  }
-
-  return `'${String(value).replace(/'/g, "''")}'`;
-}
-
-async function exportTableSql(table: string) {
-  const columnsResult = await query<{ column_name: string }>(
-    `
-      SELECT column_name
-      FROM information_schema.columns
-      WHERE table_schema = 'public'
-        AND table_name = $1
-      ORDER BY ordinal_position ASC;
-    `,
-    [table]
-  );
-  const columns = columnsResult.rows.map((row) => row.column_name);
-
-  if (columns.length === 0) {
-    return [`-- Tabelle ${table} existiert nicht im aktuellen Schema.`];
-  }
-
-  const rowsResult = await query<Record<string, unknown>>(
-    `
-      SELECT ${columns.map(quoteIdentifier).join(", ")}
-      FROM ${quoteIdentifier(table)}
-      ORDER BY ${columns.map(quoteIdentifier).join(", ")};
-    `
-  );
-
-  const lines = [`-- ${table}: ${rowsResult.rows.length} Datensatz/Datensätze`, `-- columns ${table}: ${columns.join(",")}`];
-
-  for (const row of rowsResult.rows) {
-    lines.push(
-      `INSERT INTO ${quoteIdentifier(table)} (${columns.map(quoteIdentifier).join(", ")}) VALUES (${columns.map((column) => quoteLiteral(row[column])).join(", ")});`
-    );
-  }
-
-  if (columns.includes("id")) {
-    lines.push(
-      `SELECT setval(pg_get_serial_sequence(${quoteLiteral(table)}, 'id'), COALESCE((SELECT MAX("id") FROM ${quoteIdentifier(table)}), 1), COALESCE((SELECT MAX("id") FROM ${quoteIdentifier(table)}), 0) > 0);`
-    );
-  }
-
-  return lines;
-}
-
-function restoreSqlText(sql: string) {
-  const trimmed = sql.replace(/^\uFEFF/, "").trim();
-
-  if (!trimmed.includes("TicketTracker Datenbankexport")) {
-    throw badRequest("Nur TicketTracker-SQL-Backups können eingespielt werden");
-  }
-
-  return trimmed
-    .replace(/^\s*BEGIN\s*;\s*/im, "")
-    .replace(/\s*COMMIT\s*;\s*$/im, "")
-    .replace(/TRUNCATE\s+TABLE[\s\S]*?;\s*/i, "")
-    .trim();
-}
-
-function parseDumpColumnList(value: string) {
-  const quoted = [...value.matchAll(/"((?:[^"]|"")+)"/g)].map((match) => match[1].replace(/""/g, '"'));
-
-  if (quoted.length > 0) {
-    return quoted;
-  }
-
-  return value
-    .split(",")
-    .map((column) => column.trim().replace(/^"|"$/g, ""))
-    .filter(Boolean);
-}
-
-async function currentTableColumns() {
-  const result = await query<{ table_name: string; column_name: string }>(
-    `
-      SELECT table_name, column_name
-      FROM information_schema.columns
-      WHERE table_schema = 'public'
-        AND table_name = ANY($1::text[])
-      ORDER BY table_name, ordinal_position ASC;
-    `,
-    [[...databaseExportTables]]
-  );
-  const columns = new Map<string, string[]>();
-
-  for (const row of result.rows) {
-    columns.set(row.table_name, [...(columns.get(row.table_name) ?? []), row.column_name]);
-  }
-
-  return columns;
-}
-
-async function validateTicketTrackerBackup(sql: string): Promise<RestoreValidationResult> {
-  const issues: string[] = [];
-  let body = "";
-
-  try {
-    body = restoreSqlText(sql);
-  } catch (error) {
-    return {
-      valid: false,
-      checkedTables: 0,
-      issues: [error instanceof Error ? error.message : "Backup-Datei konnte nicht gelesen werden"]
-    };
-  }
-
-  const dumpColumns = new Map<string, Set<string>>();
-
-  for (const match of sql.matchAll(/^--\s*columns\s+([a-z_][a-z0-9_]*):\s*(.+)$/gim)) {
-    dumpColumns.set(match[1], new Set(parseDumpColumnList(match[2])));
-  }
-
-  for (const match of body.matchAll(/INSERT\s+INTO\s+"?([a-z_][a-z0-9_]*)"?\s*\(([^)]+)\)\s*VALUES/gi)) {
-    const table = match[1];
-    const columns = dumpColumns.get(table) ?? new Set<string>();
-
-    for (const column of parseDumpColumnList(match[2])) {
-      columns.add(column);
-    }
-
-    dumpColumns.set(table, columns);
-  }
-
-  for (const table of dumpColumns.keys()) {
-    if (!(databaseExportTables as readonly string[]).includes(table)) {
-      issues.push(`Dump enthält unbekannte Tabelle "${table}".`);
-    }
-  }
-
-  const dbColumns = await currentTableColumns();
-
-  for (const table of databaseExportTables) {
-    const currentColumns = dbColumns.get(table) ?? [];
-    const backupColumns = dumpColumns.get(table);
-
-    if (currentColumns.length === 0) {
-      issues.push(`Aktuelle Datenbank enthält Tabelle "${table}" nicht.`);
-      continue;
-    }
-
-    if (!backupColumns) {
-      issues.push(`Dump enthält keine Strukturinformationen für Tabelle "${table}". Bitte ein aktuelles TicketTracker-Backup verwenden.`);
-      continue;
-    }
-
-    const missingInDump = currentColumns.filter((column) => !backupColumns.has(column));
-    const extraInDump = [...backupColumns].filter((column) => !currentColumns.includes(column));
-
-    if (missingInDump.length > 0) {
-      issues.push(`Dump passt nicht zu Tabelle "${table}": Feld(er) fehlen: ${missingInDump.join(", ")}.`);
-    }
-
-    if (extraInDump.length > 0) {
-      issues.push(`Dump passt nicht zu Tabelle "${table}": unbekannte Feld(er): ${extraInDump.join(", ")}.`);
-    }
-  }
-
-  return {
-    valid: issues.length === 0,
-    checkedTables: databaseExportTables.length,
-    issues
-  };
-}
-
 async function restoreTicketTrackerBackup(sql: string) {
-  const validation = await validateTicketTrackerBackup(sql);
+  const restoreId = randomUUID();
+  lastRestoreDebugState = {
+    id: restoreId,
+    startedAt: new Date().toISOString(),
+    finishedAt: null,
+    phase: "started",
+    ok: null,
+    error: null,
+    sqlBytes: Buffer.byteLength(sql, "utf8"),
+    bodyBytes: null,
+    checkedTables: null,
+    issueCount: null,
+    adminCount: null
+  };
+  updateRestoreDebug(restoreId, { phase: "validating" });
+
+  const validation = await validateBackupSql({ query }, sql);
+  updateRestoreDebug(restoreId, {
+    checkedTables: validation.checkedTables,
+    issueCount: validation.issues.length
+  });
 
   if (!validation.valid) {
+    updateRestoreDebug(restoreId, {
+      phase: "validation-failed",
+      ok: false,
+      finishedAt: new Date().toISOString(),
+      error: validation.issues[0] ?? "Restore-Datei passt nicht zur aktuellen Datenbankstruktur"
+    });
     throw badRequest(`Restore-Datei passt nicht zur aktuellen Datenbankstruktur: ${validation.issues[0]}`);
   }
 
-  const body = restoreSqlText(sql);
-
-  await withTransaction(async (client) => {
-    await client.query(`TRUNCATE TABLE ${[...databaseExportTables].reverse().map(quoteIdentifier).join(", ")} RESTART IDENTITY CASCADE;`);
-
-    if (body) {
-      await client.query(body);
-    }
-
-    const adminResult = await client.query<{ count: string }>("SELECT COUNT(*) AS count FROM users WHERE role = 'admin';");
-
-    if (Number(adminResult.rows[0]?.count ?? 0) !== 1) {
-      throw badRequest("Restore muss genau einen Admin-Benutzer enthalten");
-    }
+  updateRestoreDebug(restoreId, { phase: "preparing-sql" });
+  const body = backupRestoreSqlText(sql);
+  updateRestoreDebug(restoreId, {
+    phase: "transaction-start",
+    bodyBytes: Buffer.byteLength(body, "utf8")
   });
 
+  try {
+    await withTransaction(async (client) => {
+      updateRestoreDebug(restoreId, { phase: "lock-timeouts" });
+      await client.query("SET LOCAL lock_timeout = '10s';");
+      await client.query("SET LOCAL statement_timeout = '15min';");
+      updateRestoreDebug(restoreId, { phase: "truncate" });
+      await client.query(`TRUNCATE TABLE ${[...backupTables].reverse().map(quoteBackupIdentifier).join(", ")} RESTART IDENTITY CASCADE;`);
+
+      if (body) {
+        updateRestoreDebug(restoreId, { phase: "import-body" });
+        await client.query(body);
+      }
+
+      updateRestoreDebug(restoreId, { phase: "verify-admin" });
+      const adminResult = await client.query<{ count: string }>("SELECT COUNT(*) AS count FROM users WHERE role = 'admin';");
+      const adminCount = Number(adminResult.rows[0]?.count ?? 0);
+      updateRestoreDebug(restoreId, { adminCount });
+
+      if (adminCount !== 1) {
+        throw badRequest("Restore muss genau einen Admin-Benutzer enthalten");
+      }
+    });
+  } catch (error) {
+    updateRestoreDebug(restoreId, {
+      ok: false,
+      finishedAt: new Date().toISOString(),
+      error: error instanceof Error ? error.message : "Unbekannter Restore-Fehler"
+    });
+    throw error;
+  }
+
+  updateRestoreDebug(restoreId, {
+    phase: "finished",
+    ok: true,
+    finishedAt: new Date().toISOString()
+  });
   return { ok: true };
 }
 
 app.get("/api/admin/export/database", requireAdmin, async (_req, res) => {
-  const lines = [
-    "-- TicketTracker Datenbankexport",
-    `-- Erstellt: ${new Date().toISOString()}`,
-    "-- Restore: frische TicketTracker-Datenbank migrieren lassen, danach diese Datei mit psql einspielen.",
-    "BEGIN;",
-    `TRUNCATE TABLE ${[...databaseExportTables].reverse().map(quoteIdentifier).join(", ")} RESTART IDENTITY CASCADE;`
-  ];
-
-  for (const table of databaseExportTables) {
-    lines.push("", ...(await exportTableSql(table)));
-  }
-
-  lines.push("", "COMMIT;", "");
+  const sql = await withTransaction(async (client) => {
+    await client.query("SET TRANSACTION ISOLATION LEVEL REPEATABLE READ, READ ONLY;");
+    return exportDatabaseSql(client);
+  });
 
   const timestamp = new Date().toISOString().replace(/[:.]/g, "-");
   res.setHeader("Content-Type", "application/sql; charset=utf-8");
   res.setHeader("Content-Disposition", `attachment; filename="tickettracker-backup-${timestamp}.sql"`);
-  res.send(lines.join("\n"));
+  res.send(sql);
 });
 
 app.post("/api/admin/restore/database/validate", requireAdmin, async (req, res) => {
   const sql = restoreSqlFromRequestBody(req.body);
-  res.json(await validateTicketTrackerBackup(sql));
+  res.json(await validateBackupSql({ query }, sql));
 });
 
 app.post("/api/admin/restore/database", requireAdmin, async (req, res) => {
@@ -7812,10 +7721,25 @@ app.use((error: Error & { status?: number; statusCode?: number; type?: string },
 });
 
 async function start() {
+  logDebug("startup", {
+    phase: "migrate-start",
+    port,
+    serveFrontend,
+    requestBodyLimit
+  });
   await migrate();
+  const adminResult = await query<{ count: string }>("SELECT COUNT(*) AS count FROM users WHERE role = 'admin';");
+  logDebug("startup", {
+    phase: "migrate-finished",
+    adminCount: Number(adminResult.rows[0]?.count ?? 0)
+  });
 
   const server = app.listen(port, () => {
     console.log(`TicketTracker listening on port ${port}`);
+    logDebug("startup", {
+      phase: "listening",
+      port
+    });
   });
 
   const shutdown = async () => {
diff --git a/backend/test/databaseExport.test.ts b/backend/test/databaseExport.test.ts
new file mode 100644
index 0000000..b7778ba
--- /dev/null
+++ b/backend/test/databaseExport.test.ts
@@ -0,0 +1,97 @@
+import assert from "node:assert/strict";
+import test from "node:test";
+import { nextSequenceIdAfterRestore, restoreSqlText, sequenceSetvalSql, sqlLiteral, type QueryExecutor } from "../src/databaseExport.ts";
+import { exportTableSql } from "../src/databaseExport.ts";
+
+const jsonbColumn = { dataType: "jsonb", udtName: "jsonb" };
+
+test("sqlLiteral serializes primitive values", () => {
+  assert.equal(sqlLiteral(null), "NULL");
+  assert.equal(sqlLiteral(undefined), "NULL");
+  assert.equal(sqlLiteral("normaler Text"), "'normaler Text'");
+  assert.equal(sqlLiteral("O'Brien"), "'O''Brien'");
+  assert.equal(sqlLiteral("erste Zeile\nzweite Zeile"), "'erste Zeile\nzweite Zeile'");
+  assert.equal(sqlLiteral("Grüße"), "'Grüße'");
+  assert.equal(sqlLiteral(true), "TRUE");
+  assert.equal(sqlLiteral(false), "FALSE");
+  assert.equal(sqlLiteral(0), "0");
+  assert.equal(sqlLiteral(42), "42");
+  assert.equal(sqlLiteral(-10), "-10");
+  assert.equal(sqlLiteral(1.25), "1.25");
+});
+
+test("sqlLiteral serializes dates, buffers, objects and arrays", () => {
+  assert.equal(sqlLiteral(new Date("2026-09-11T10:15:30.000Z")), "'2026-09-11T10:15:30.000Z'");
+  assert.equal(sqlLiteral(Buffer.from("abc")), "decode('616263', 'hex')");
+  assert.equal(sqlLiteral({}), "'{}'");
+  assert.equal(sqlLiteral([]), "'[]'");
+  assert.equal(sqlLiteral({ foo: "bar" }), `'{"foo":"bar"}'`);
+  assert.equal(sqlLiteral({ foo: "O'Brien" }), `'{"foo":"O''Brien"}'`);
+  assert.equal(sqlLiteral({ nested: { enabled: true }, items: [{ id: 1 }] }), `'{"nested":{"enabled":true},"items":[{"id":1}]}'`);
+});
+
+test("sqlLiteral serializes JSON columns as valid JSON values", () => {
+  assert.equal(sqlLiteral({ foo: "bar", enabled: true }, jsonbColumn), `'{"foo":"bar","enabled":true}'`);
+  assert.equal(sqlLiteral("plain json string", jsonbColumn), `'"plain json string"'`);
+  assert.equal(sqlLiteral(true, jsonbColumn), "'true'");
+});
+
+test("generated table export never contains implicit object stringification", async () => {
+  const client: QueryExecutor = {
+    async query<T extends Record<string, unknown>>(text: string): Promise<{ rows: T[]; rowCount: number | null }> {
+      if (text.includes("information_schema.columns")) {
+        return {
+          rowCount: 3,
+          rows: [
+            { columnName: "id", dataType: "bigint", udtName: "int8", ordinalPosition: 1, isNullable: "NO" },
+            { columnName: "value", dataType: "jsonb", udtName: "jsonb", ordinalPosition: 2, isNullable: "NO" },
+            { columnName: "label", dataType: "text", udtName: "text", ordinalPosition: 3, isNullable: "YES" }
+          ] as T[]
+        };
+      }
+
+      if (text.includes("pg_get_serial_sequence")) {
+        return { rowCount: 1, rows: [{ sequenceName: "public.example_id_seq" }] as T[] };
+      }
+
+      return {
+        rowCount: 1,
+        rows: [{ id: 4, value: { foo: "bar" }, label: "O'Brien" }] as T[]
+      };
+    }
+  };
+
+  const sql = (await exportTableSql(client, "example")).join("\n");
+  assert.doesNotMatch(sql, /\[object Object\]/);
+  assert.match(sql, /'\{"foo":"bar"\}'/);
+});
+
+test("sequence helper advances after restored max id", () => {
+  assert.equal(nextSequenceIdAfterRestore(4), 5);
+  assert.equal(nextSequenceIdAfterRestore(null), 1);
+  assert.match(sequenceSetvalSql("users", "public.users_id_seq"), /SELECT setval\('public\.users_id_seq'/);
+  assert.match(sequenceSetvalSql("users", "public.users_id_seq"), /MAX\("id"\) FROM "users"/);
+});
+
+test("restoreSqlText removes dump transaction wrapper after export header", () => {
+  const body = restoreSqlText(`
+-- TicketTracker Datenbankexport
+-- Erstellt: 2026-09-14T10:00:00.000Z
+
+BEGIN;
+SET LOCAL lock_timeout = '10s';
+SET LOCAL statement_timeout = '15min';
+TRUNCATE TABLE "users", "auth_sessions" RESTART IDENTITY CASCADE;
+
+INSERT INTO "users" ("id", "username") VALUES
+  (1, 'admin');
+
+COMMIT;
+`);
+
+  assert.doesNotMatch(body, /^\s*BEGIN\s*;/im);
+  assert.doesNotMatch(body, /^\s*COMMIT\s*;/im);
+  assert.doesNotMatch(body, /^\s*SET\s+LOCAL/im);
+  assert.doesNotMatch(body, /TRUNCATE\s+TABLE/i);
+  assert.match(body, /INSERT INTO "users"/);
+});
diff --git a/frontend/src/api.ts b/frontend/src/api.ts
index 9a47e00..53ce125 100644
--- a/frontend/src/api.ts
+++ b/frontend/src/api.ts
@@ -159,6 +159,10 @@ async function request<T>(url: string, options: ApiRequestInit = {}): Promise<T>
   return response.json() as Promise<T>;
 }
 
+async function requestRestoreEndpoint<T>(path: string, options: ApiRequestInit) {
+  return request<T>(path, options);
+}
+
 export function login(payload: { username: string; password: string }) {
   return request<{ user: AuthUser }>("/api/auth/login", {
     method: "POST",
@@ -225,7 +229,7 @@ export function createSetupAdmin(payload: { username: string; displayName: strin
 }
 
 export function restoreSetupBackup(sql: string) {
-  return request<{ ok: boolean }>("/api/setup/restore", {
+  return requestRestoreEndpoint<{ ok: boolean }>("/api/setup/restore", {
     method: "POST",
     timeoutMs: 10 * 60 * 1000,
     headers: { "Content-Type": "text/plain; charset=utf-8" },
@@ -234,9 +238,9 @@ export function restoreSetupBackup(sql: string) {
 }
 
 export function validateSetupBackup(sql: string) {
-  return request<RestoreValidationResult>("/api/setup/restore/validate", {
+  return requestRestoreEndpoint<RestoreValidationResult>("/api/setup/restore/validate", {
     method: "POST",
-    timeoutMs: 10 * 60 * 1000,
+    timeoutMs: 60_000,
     headers: { "Content-Type": "text/plain; charset=utf-8" },
     body: sql
   });
@@ -293,7 +297,7 @@ export async function downloadDatabaseExport() {
 }
 
 export function restoreDatabaseBackup(sql: string) {
-  return request<{ ok: boolean }>("/api/admin/restore/database", {
+  return requestRestoreEndpoint<{ ok: boolean }>("/api/admin/restore/database", {
     method: "POST",
     timeoutMs: 10 * 60 * 1000,
     headers: { "Content-Type": "text/plain; charset=utf-8" },
@@ -302,9 +306,9 @@ export function restoreDatabaseBackup(sql: string) {
 }
 
 export function validateDatabaseBackup(sql: string) {
-  return request<RestoreValidationResult>("/api/admin/restore/database/validate", {
+  return requestRestoreEndpoint<RestoreValidationResult>("/api/admin/restore/database/validate", {
     method: "POST",
-    timeoutMs: 10 * 60 * 1000,
+    timeoutMs: 60_000,
     headers: { "Content-Type": "text/plain; charset=utf-8" },
     body: sql
   });
diff --git a/scripts/install-local-dependencies.sh b/scripts/install-local-dependencies.sh
old mode 100755
new mode 100644
index 0a1cd9a..50826d9
--- a/scripts/install-local-dependencies.sh
+++ b/scripts/install-local-dependencies.sh
@@ -3,10 +3,22 @@ set -euo pipefail
 
 NODE_MAJOR_REQUIRED=22
 NODESOURCE_SETUP_URL="https://deb.nodesource.com/setup_${NODE_MAJOR_REQUIRED}.x"
+MIN_DISK_MB=2048
+MIN_MEMORY_MB=768
 
 SCRIPT_DIR="$(cd -- "$(dirname -- "${BASH_SOURCE[0]}")" && pwd)"
 REPO_ROOT="$(cd -- "${SCRIPT_DIR}/.." && pwd)"
 
+if [[ "${1:-}" != "--run" ]]; then
+  echo "Dieses Setup-Script macht ohne explizites --run nichts."
+  echo
+  echo "So startest du es bewusst:"
+  echo "  bash scripts/install-local-dependencies.sh --run"
+  echo
+  echo "Es installiert nur Webapp-Abhaengigkeiten, keine DB und kein Docker."
+  exit 0
+fi
+
 if [[ ! -f "${REPO_ROOT}/package.json" ]]; then
   echo "Repo-Root nicht gefunden. Erwartet: ${REPO_ROOT}/package.json"
   exit 1
@@ -46,6 +58,33 @@ node_major() {
   node -p 'Number(process.versions.node.split(".")[0])' 2>/dev/null || echo 0
 }
 
+available_memory_mb() {
+  awk '/MemAvailable:/ { print int($2 / 1024) }' /proc/meminfo 2>/dev/null || echo 0
+}
+
+available_disk_mb() {
+  df -Pm "${REPO_ROOT}" | awk 'NR == 2 { print $4 }'
+}
+
+if [[ "${SKIP_RESOURCE_CHECK:-false}" != "true" ]]; then
+  AVAILABLE_DISK_MB="$(available_disk_mb)"
+  AVAILABLE_MEMORY_MB="$(available_memory_mb)"
+
+  if [[ "${AVAILABLE_DISK_MB}" -lt "${MIN_DISK_MB}" ]]; then
+    echo "Zu wenig freier Speicherplatz fuer npm-Abhaengigkeiten."
+    echo "Frei: ${AVAILABLE_DISK_MB} MB, benoetigt empfohlen: mindestens ${MIN_DISK_MB} MB."
+    echo "Falls du das bewusst trotzdem starten willst: SKIP_RESOURCE_CHECK=true bash scripts/install-local-dependencies.sh --run"
+    exit 1
+  fi
+
+  if [[ "${AVAILABLE_MEMORY_MB}" -gt 0 && "${AVAILABLE_MEMORY_MB}" -lt "${MIN_MEMORY_MB}" ]]; then
+    echo "Zu wenig freier Arbeitsspeicher fuer eine stabile npm-Installation."
+    echo "Frei: ${AVAILABLE_MEMORY_MB} MB, benoetigt empfohlen: mindestens ${MIN_MEMORY_MB} MB."
+    echo "Falls Swap vorhanden ist und du das bewusst trotzdem starten willst: SKIP_RESOURCE_CHECK=true bash scripts/install-local-dependencies.sh --run"
+    exit 1
+  fi
+fi
+
 echo "Installiere Basiswerkzeuge fuer die lokale Webapp..."
 run_apt update
 run_apt install -y ca-certificates curl gnupg git bash build-essential