diff --git a/app/Console/Commands/ContactsFindDuplicates.php b/app/Console/Commands/ContactsFindDuplicates.php
new file mode 100644
index 0000000..cef982d
--- /dev/null
+++ b/app/Console/Commands/ContactsFindDuplicates.php
@@ -0,0 +1,160 @@
+<?php
+
+namespace App\Console\Commands;
+
+use Illuminate\Console\Command;
+use Illuminate\Support\Facades\DB;
+
+/**
+ * Phase 1 — Schritt 1: Duplikate identifizieren
+ *
+ * Sucht Kunden-Datensätze, die vermutlich dieselbe Person repräsentieren.
+ * Drei Erkennungs-Stufen (absteigend nach Konfidenz):
+ *
+ *   HIGH   — gleiche E-Mail (nicht leer)
+ *   MEDIUM — gleicher Name + Vorname + Geburtsdatum
+ *   LOW    — gleicher Name + Vorname + PLZ
+ *
+ * Verwendung:
+ *   php artisan contacts:find-duplicates
+ *   php artisan contacts:find-duplicates --export=duplicates.csv
+ *   php artisan contacts:find-duplicates --confidence=HIGH
+ */
+class ContactsFindDuplicates extends Command
+{
+    protected $signature = 'contacts:find-duplicates
+                            {--export= : Pfad zur CSV-Ausgabedatei}
+                            {--confidence= : Nur diese Konfidenz-Stufe ausgeben (HIGH|MEDIUM|LOW)}';
+
+    protected $description = 'Identifiziert doppelte Customer-Datensätze anhand von E-Mail, Name/Geburtsdatum oder Name/PLZ';
+
+    public function handle(): int
+    {
+        $this->info('Suche nach Duplikaten in der customer-Tabelle...');
+        $this->newLine();
+
+        $groups = collect();
+
+        // ── HIGH: gleiche E-Mail ──────────────────────────────────────────
+        if ($this->shouldCheck('HIGH')) {
+            $emailDupes = DB::table('customer')
+                ->select('email', DB::raw('COUNT(*) as cnt'), DB::raw('GROUP_CONCAT(id ORDER BY updated_at DESC) as ids'))
+                ->whereNotNull('email')
+                ->where('email', '!=', '')
+                ->whereNull('merged_into_id')
+                ->groupBy('email')
+                ->having('cnt', '>', 1)
+                ->get();
+
+            foreach ($emailDupes as $row) {
+                $groups->push([
+                    'confidence' => 'HIGH',
+                    'reason'     => 'E-Mail: ' . $row->email,
+                    'ids'        => $row->ids,
+                    'count'      => $row->cnt,
+                ]);
+            }
+
+            $this->line(sprintf('<fg=green>HIGH</> (gleiche E-Mail):   %d Gruppen', $emailDupes->count()));
+        }
+
+        // ── MEDIUM: Name + Vorname + Geburtsdatum ────────────────────────
+        if ($this->shouldCheck('MEDIUM')) {
+            $nameBdDupes = DB::table('customer')
+                ->select(
+                    'name', 'firstname', 'birthdate',
+                    DB::raw('COUNT(*) as cnt'),
+                    DB::raw('GROUP_CONCAT(id ORDER BY updated_at DESC) as ids')
+                )
+                ->whereNotNull('name')
+                ->whereNotNull('firstname')
+                ->whereNotNull('birthdate')
+                ->whereNull('merged_into_id')
+                ->groupBy('name', 'firstname', 'birthdate')
+                ->having('cnt', '>', 1)
+                ->get();
+
+            foreach ($nameBdDupes as $row) {
+                $groups->push([
+                    'confidence' => 'MEDIUM',
+                    'reason'     => "Name: {$row->firstname} {$row->name}, GD: {$row->birthdate}",
+                    'ids'        => $row->ids,
+                    'count'      => $row->cnt,
+                ]);
+            }
+
+            $this->line(sprintf('<fg=yellow>MEDIUM</> (Name+GD):         %d Gruppen', $nameBdDupes->count()));
+        }
+
+        // ── LOW: Name + Vorname + PLZ ─────────────────────────────────────
+        if ($this->shouldCheck('LOW')) {
+            $nameZipDupes = DB::table('customer')
+                ->select(
+                    'name', 'firstname', 'zip',
+                    DB::raw('COUNT(*) as cnt'),
+                    DB::raw('GROUP_CONCAT(id ORDER BY updated_at DESC) as ids')
+                )
+                ->whereNotNull('name')
+                ->whereNotNull('firstname')
+                ->whereNotNull('zip')
+                ->where('zip', '!=', '')
+                ->whereNull('merged_into_id')
+                ->groupBy('name', 'firstname', 'zip')
+                ->having('cnt', '>', 1)
+                ->get();
+
+            foreach ($nameZipDupes as $row) {
+                $groups->push([
+                    'confidence' => 'LOW',
+                    'reason'     => "Name: {$row->firstname} {$row->name}, PLZ: {$row->zip}",
+                    'ids'        => $row->ids,
+                    'count'      => $row->cnt,
+                ]);
+            }
+
+            $this->line(sprintf('<fg=red>LOW</> (Name+PLZ):           %d Gruppen', $nameZipDupes->count()));
+        }
+
+        $this->newLine();
+        $this->info(sprintf('Gesamt: %d Duplikat-Gruppen gefunden', $groups->count()));
+
+        if ($groups->isEmpty()) {
+            $this->info('Keine Duplikate — nichts zu tun.');
+            return self::SUCCESS;
+        }
+
+        // Tabellen-Ausgabe
+        $this->table(
+            ['Konfidenz', 'Grund', 'IDs (neueste zuerst)', 'Anzahl'],
+            $groups->map(fn ($g) => [$g['confidence'], $g['reason'], $g['ids'], $g['count']])->all()
+        );
+
+        // CSV-Export
+        if ($export = $this->option('export')) {
+            $this->exportCsv($groups->all(), $export);
+            $this->info("CSV gespeichert: {$export}");
+        } else {
+            $this->newLine();
+            $this->line('Tipp: --export=duplicates.csv für CSV-Export');
+            $this->line('Tipp: php artisan contacts:merge-duplicates --dry-run  zum Prüfen');
+        }
+
+        return self::SUCCESS;
+    }
+
+    private function shouldCheck(string $level): bool
+    {
+        $filter = strtoupper((string) $this->option('confidence'));
+        return $filter === '' || $filter === $level;
+    }
+
+    private function exportCsv(array $groups, string $path): void
+    {
+        $handle = fopen($path, 'w');
+        fputcsv($handle, ['Konfidenz', 'Grund', 'IDs (neueste zuerst)', 'Anzahl']);
+        foreach ($groups as $group) {
+            fputcsv($handle, [$group['confidence'], $group['reason'], $group['ids'], $group['count']]);
+        }
+        fclose($handle);
+    }
+}
diff --git a/app/Console/Commands/ContactsMergeDuplicates.php b/app/Console/Commands/ContactsMergeDuplicates.php
new file mode 100644
index 0000000..e51ca46
--- /dev/null
+++ b/app/Console/Commands/ContactsMergeDuplicates.php
@@ -0,0 +1,233 @@
+<?php
+
+namespace App\Console\Commands;
+
+use Illuminate\Console\Command;
+use Illuminate\Support\Facades\DB;
+
+/**
+ * Phase 1 — Schritt 2: Duplikate zusammenführen
+ *
+ * Strategie: Der neueste Datensatz (höchstes updated_at, dann höchste id)
+ * wird Master. Alle anderen Datensätze derselben Gruppe erhalten
+ * merged_into_id = master_id und werden nicht mehr zurückgegeben.
+ *
+ * Alle FK-Referenzen in lead, booking, customer_mails, lead_mails
+ * werden auf den Master umgestellt.
+ *
+ * Verwendung:
+ *   php artisan contacts:merge-duplicates --dry-run          # Vorschau, keine Änderung
+ *   php artisan contacts:merge-duplicates --confidence=HIGH  # Nur sichere Duplikate
+ *   php artisan contacts:merge-duplicates                    # Ausführen
+ */
+class ContactsMergeDuplicates extends Command
+{
+    protected $signature = 'contacts:merge-duplicates
+                            {--dry-run : Zeigt was passieren würde, ohne Daten zu ändern}
+                            {--confidence= : Nur diese Konfidenz-Stufe verarbeiten (HIGH|MEDIUM|LOW)}
+                            {--force : Überspringt Sicherheitsabfrage}';
+
+    protected $description = 'Führt doppelte Customer-Datensätze zusammen (neuester wird Master)';
+
+    private bool $dryRun = false;
+    private int $mergedCount = 0;
+    private int $updatedLeads = 0;
+    private int $updatedBookings = 0;
+
+    public function handle(): int
+    {
+        $this->dryRun = (bool) $this->option('dry-run');
+
+        if ($this->dryRun) {
+            $this->warn('DRY-RUN Modus — keine Daten werden verändert');
+        } else {
+            $this->warn('ACHTUNG: Diese Operation verändert Produktionsdaten.');
+            if (!$this->option('force') && !$this->confirm('Fortfahren?')) {
+                $this->info('Abgebrochen.');
+                return self::SUCCESS;
+            }
+        }
+
+        $this->newLine();
+
+        DB::transaction(function () {
+            $this->processLevel(
+                'HIGH',
+                fn () => $this->findByEmail()
+            );
+
+            $this->processLevel(
+                'MEDIUM',
+                fn () => $this->findByNameBirthdate()
+            );
+
+            $this->processLevel(
+                'LOW',
+                fn () => $this->findByNameZip()
+            );
+        });
+
+        $this->newLine();
+        $this->info(sprintf(
+            '%s %d Duplikate zusammengeführt | %d leads aktualisiert | %d bookings aktualisiert',
+            $this->dryRun ? '[DRY-RUN]' : '',
+            $this->mergedCount,
+            $this->updatedLeads,
+            $this->updatedBookings
+        ));
+
+        if ($this->dryRun) {
+            $this->newLine();
+            $this->line('Zum Ausführen: php artisan contacts:merge-duplicates');
+        }
+
+        return self::SUCCESS;
+    }
+
+    // ─────────────────────────────────────────────────────────────────────────
+    // Duplikat-Gruppen ermitteln
+    // ─────────────────────────────────────────────────────────────────────────
+
+    private function findByEmail(): array
+    {
+        return DB::table('customer')
+            ->select('email', DB::raw('GROUP_CONCAT(id ORDER BY updated_at DESC, id DESC) as ids'))
+            ->whereNotNull('email')
+            ->where('email', '!=', '')
+            ->whereNull('merged_into_id')
+            ->groupBy('email')
+            ->having(DB::raw('COUNT(*)'), '>', 1)
+            ->pluck('ids')
+            ->map(fn ($ids) => explode(',', $ids))
+            ->all();
+    }
+
+    private function findByNameBirthdate(): array
+    {
+        return DB::table('customer')
+            ->select(DB::raw('GROUP_CONCAT(id ORDER BY updated_at DESC, id DESC) as ids'))
+            ->whereNotNull('name')
+            ->whereNotNull('firstname')
+            ->whereNotNull('birthdate')
+            ->whereNull('merged_into_id')
+            ->groupBy('name', 'firstname', 'birthdate')
+            ->having(DB::raw('COUNT(*)'), '>', 1)
+            ->pluck('ids')
+            ->map(fn ($ids) => explode(',', $ids))
+            ->all();
+    }
+
+    private function findByNameZip(): array
+    {
+        return DB::table('customer')
+            ->select(DB::raw('GROUP_CONCAT(id ORDER BY updated_at DESC, id DESC) as ids'))
+            ->whereNotNull('name')
+            ->whereNotNull('firstname')
+            ->whereNotNull('zip')
+            ->where('zip', '!=', '')
+            ->whereNull('merged_into_id')
+            ->groupBy('name', 'firstname', 'zip')
+            ->having(DB::raw('COUNT(*)'), '>', 1)
+            ->pluck('ids')
+            ->map(fn ($ids) => explode(',', $ids))
+            ->all();
+    }
+
+    // ─────────────────────────────────────────────────────────────────────────
+    // Verarbeitung
+    // ─────────────────────────────────────────────────────────────────────────
+
+    private function processLevel(string $level, callable $finder): void
+    {
+        if ($filter = $this->option('confidence')) {
+            if (strtoupper($filter) !== $level) {
+                return;
+            }
+        }
+
+        $groups = $finder();
+
+        if (empty($groups)) {
+            $this->line("[{$level}] Keine Duplikate.");
+            return;
+        }
+
+        $this->line(sprintf('[%s] %d Gruppe(n) gefunden', $level, count($groups)));
+
+        foreach ($groups as $ids) {
+            $masterId  = (int) $ids[0];           // erster = neuester
+            $duplicateIds = array_map('intval', array_slice($ids, 1));
+
+            $this->line(sprintf(
+                '  Master: #%d  ←  Duplikate: %s',
+                $masterId,
+                implode(', ', array_map(fn ($id) => '#' . $id, $duplicateIds))
+            ));
+
+            foreach ($duplicateIds as $dupeId) {
+                $this->mergeInto($masterId, $dupeId);
+            }
+        }
+    }
+
+    private function mergeInto(int $masterId, int $dupeId): void
+    {
+        // 1. Leads umhängen
+        $leadCount = DB::table('lead')->where('customer_id', $dupeId)->count();
+        if ($leadCount > 0) {
+            $this->line("    lead.customer_id: {$leadCount} Zeile(n) → #{$masterId}");
+            if (!$this->dryRun) {
+                DB::table('lead')
+                    ->where('customer_id', $dupeId)
+                    ->update(['customer_id' => $masterId]);
+            }
+            $this->updatedLeads += $leadCount;
+        }
+
+        // 2. Bookings umhängen
+        $bookingCount = DB::table('booking')->where('customer_id', $dupeId)->count();
+        if ($bookingCount > 0) {
+            $this->line("    booking.customer_id: {$bookingCount} Zeile(n) → #{$masterId}");
+            if (!$this->dryRun) {
+                DB::table('booking')
+                    ->where('customer_id', $dupeId)
+                    ->update(['customer_id' => $masterId]);
+            }
+            $this->updatedBookings += $bookingCount;
+        }
+
+        // 3. customer_mails umhängen
+        $mailCount = DB::table('customer_mails')->where('customer_id', $dupeId)->count();
+        if ($mailCount > 0) {
+            $this->line("    customer_mails.customer_id: {$mailCount} Zeile(n) → #{$masterId}");
+            if (!$this->dryRun) {
+                DB::table('customer_mails')
+                    ->where('customer_id', $dupeId)
+                    ->update(['customer_id' => $masterId]);
+            }
+        }
+
+        // 4. lead_mails umhängen
+        $leadMailCount = DB::table('lead_mails')->where('customer_id', $dupeId)->count();
+        if ($leadMailCount > 0) {
+            $this->line("    lead_mails.customer_id: {$leadMailCount} Zeile(n) → #{$masterId}");
+            if (!$this->dryRun) {
+                DB::table('lead_mails')
+                    ->where('customer_id', $dupeId)
+                    ->update(['customer_id' => $masterId]);
+            }
+        }
+
+        // 5. Duplikat als zusammengeführt markieren
+        if (!$this->dryRun) {
+            DB::table('customer')
+                ->where('id', $dupeId)
+                ->update([
+                    'merged_into_id' => $masterId,
+                    'merged_at'      => now(),
+                ]);
+        }
+
+        $this->mergedCount++;
+    }
+}