diff --git a/src/app/(dashboard)/customers/components/customer-form-sheet.tsx b/src/app/(dashboard)/customers/components/customer-form-sheet.tsx
new file mode 100644
index 0000000..530e5d9
--- /dev/null
+++ b/src/app/(dashboard)/customers/components/customer-form-sheet.tsx
@@ -0,0 +1,187 @@
+"use client";
+
+import { useActionState, useEffect } from "react";
+import { Loader2, Save } from "lucide-react";
+import { toast } from "sonner";
+
+import { Button } from "@/components/ui/button";
+import { Input } from "@/components/ui/input";
+import { Label } from "@/components/ui/label";
+import {
+  Select,
+  SelectContent,
+  SelectItem,
+  SelectTrigger,
+  SelectValue,
+} from "@/components/ui/select";
+import {
+  Sheet,
+  SheetContent,
+  SheetDescription,
+  SheetFooter,
+  SheetHeader,
+  SheetTitle,
+} from "@/components/ui/sheet";
+import { Textarea } from "@/components/ui/textarea";
+import {
+  createCustomerAction,
+  updateCustomerAction,
+} from "@/lib/appwrite/customer-actions";
+import { initialCustomerState } from "@/lib/appwrite/customer-types";
+import type { CustomerRow } from "./types";
+
+type Props = {
+  open: boolean;
+  onOpenChange: (v: boolean) => void;
+  customer?: CustomerRow | null;
+};
+
+export function CustomerFormSheet({ open, onOpenChange, customer }: Props) {
+  const isEdit = Boolean(customer);
+  const action = isEdit ? updateCustomerAction : createCustomerAction;
+  const [state, formAction, isPending] = useActionState(action, initialCustomerState);
+
+  useEffect(() => {
+    if (state.ok) {
+      toast.success(isEdit ? "Müşteri güncellendi." : "Müşteri eklendi.");
+      onOpenChange(false);
+    } else if (state.error) {
+      toast.error(state.error);
+    }
+    // eslint-disable-next-line react-hooks/exhaustive-deps
+  }, [state]);
+
+  return (
+    <Sheet open={open} onOpenChange={onOpenChange}>
+      <SheetContent className="flex w-full flex-col gap-0 p-0 sm:max-w-xl">
+        <SheetHeader className="border-b px-6 py-4">
+          <SheetTitle>{isEdit ? "Müşteriyi düzenle" : "Yeni müşteri"}</SheetTitle>
+          <SheetDescription>
+            {isEdit
+              ? "Müşteri bilgilerini güncelleyin."
+              : "Yeni bir müşteri ekleyin. * işaretli alanlar zorunludur."}
+          </SheetDescription>
+        </SheetHeader>
+
+        <form action={formAction} className="flex flex-1 flex-col">
+          {isEdit && customer && <input type="hidden" name="id" value={customer.id} />}
+
+          <div className="flex-1 space-y-4 overflow-y-auto px-6 py-5">
+            <div className="grid gap-2">
+              <Label htmlFor="name">Ad / Şirket adı *</Label>
+              <Input
+                id="name"
+                name="name"
+                defaultValue={customer?.name ?? ""}
+                placeholder="Örn. Acme Yazılım Ltd."
+                required
+              />
+              {state.fieldErrors?.name && (
+                <p className="text-destructive text-xs">{state.fieldErrors.name}</p>
+              )}
+            </div>
+
+            <div className="grid gap-4 md:grid-cols-2">
+              <div className="grid gap-2">
+                <Label htmlFor="email">Email</Label>
+                <Input
+                  id="email"
+                  name="email"
+                  type="email"
+                  defaultValue={customer?.email ?? ""}
+                  placeholder="info@acme.com"
+                />
+                {state.fieldErrors?.email && (
+                  <p className="text-destructive text-xs">{state.fieldErrors.email}</p>
+                )}
+              </div>
+              <div className="grid gap-2">
+                <Label htmlFor="phone">Telefon</Label>
+                <Input
+                  id="phone"
+                  name="phone"
+                  type="tel"
+                  defaultValue={customer?.phone ?? ""}
+                  placeholder="+90 555 123 45 67"
+                />
+              </div>
+            </div>
+
+            <div className="grid gap-4 md:grid-cols-2">
+              <div className="grid gap-2">
+                <Label htmlFor="taxId">Vergi numarası</Label>
+                <Input
+                  id="taxId"
+                  name="taxId"
+                  defaultValue={customer?.taxId ?? ""}
+                  placeholder="1234567890"
+                  inputMode="numeric"
+                />
+              </div>
+              <div className="grid gap-2">
+                <Label htmlFor="status">Durum</Label>
+                <Select name="status" defaultValue={customer?.status ?? "active"}>
+                  <SelectTrigger id="status">
+                    <SelectValue />
+                  </SelectTrigger>
+                  <SelectContent>
+                    <SelectItem value="active">Aktif</SelectItem>
+                    <SelectItem value="passive">Pasif</SelectItem>
+                  </SelectContent>
+                </Select>
+              </div>
+            </div>
+
+            <div className="grid gap-2">
+              <Label htmlFor="address">Adres</Label>
+              <Textarea
+                id="address"
+                name="address"
+                rows={2}
+                defaultValue={customer?.address ?? ""}
+                placeholder="Açık adres"
+              />
+            </div>
+
+            <div className="grid gap-2">
+              <Label htmlFor="notes">Notlar</Label>
+              <Textarea
+                id="notes"
+                name="notes"
+                rows={4}
+                defaultValue={customer?.notes ?? ""}
+                placeholder="Müşteriye özel notlar"
+              />
+            </div>
+          </div>
+
+          <SheetFooter className="border-t bg-muted/30 px-6 py-4">
+            <div className="flex w-full justify-end gap-2">
+              <Button
+                type="button"
+                variant="outline"
+                onClick={() => onOpenChange(false)}
+                disabled={isPending}
+              >
+                Vazgeç
+              </Button>
+              <Button type="submit" disabled={isPending}>
+                {isPending ? (
+                  <>
+                    <Loader2 className="size-4 animate-spin" />
+                    Kaydediliyor...
+                  </>
+                ) : (
+                  <>
+                    <Save className="size-4" />
+                    {isEdit ? "Güncelle" : "Kaydet"}
+                  </>
+                )}
+              </Button>
+            </div>
+          </SheetFooter>
+        </form>
+      </SheetContent>
+    </Sheet>
+  );
+}
diff --git a/src/app/(dashboard)/customers/components/customers-client.tsx b/src/app/(dashboard)/customers/components/customers-client.tsx
new file mode 100644
index 0000000..18d7575
--- /dev/null
+++ b/src/app/(dashboard)/customers/components/customers-client.tsx
@@ -0,0 +1,314 @@
+"use client";
+
+import { useMemo, useState } from "react";
+import {
+  type ColumnDef,
+  type SortingState,
+  flexRender,
+  getCoreRowModel,
+  getFilteredRowModel,
+  getPaginationRowModel,
+  getSortedRowModel,
+  useReactTable,
+} from "@tanstack/react-table";
+import {
+  ArrowUpDown,
+  ChevronLeft,
+  ChevronRight,
+  MoreHorizontal,
+  Pencil,
+  Plus,
+  Search,
+  Trash2,
+  UserPlus,
+} from "lucide-react";
+
+import { Badge } from "@/components/ui/badge";
+import { Button } from "@/components/ui/button";
+import { Card, CardContent } from "@/components/ui/card";
+import {
+  DropdownMenu,
+  DropdownMenuContent,
+  DropdownMenuItem,
+  DropdownMenuTrigger,
+} from "@/components/ui/dropdown-menu";
+import { Input } from "@/components/ui/input";
+import {
+  Table,
+  TableBody,
+  TableCell,
+  TableHead,
+  TableHeader,
+  TableRow,
+} from "@/components/ui/table";
+
+import { CustomerFormSheet } from "./customer-form-sheet";
+import { DeleteCustomerDialog } from "./delete-customer-dialog";
+import type { CustomerRow } from "./types";
+
+type Props = { customers: CustomerRow[] };
+
+export function CustomersClient({ customers }: Props) {
+  const [globalFilter, setGlobalFilter] = useState("");
+  const [sorting, setSorting] = useState<SortingState>([]);
+  const [formOpen, setFormOpen] = useState(false);
+  const [editing, setEditing] = useState<CustomerRow | null>(null);
+  const [deleting, setDeleting] = useState<CustomerRow | null>(null);
+
+  const columns = useMemo<ColumnDef<CustomerRow>[]>(
+    () => [
+      {
+        accessorKey: "name",
+        header: ({ column }) => (
+          <Button
+            variant="ghost"
+            size="sm"
+            className="-ml-3 h-8"
+            onClick={() => column.toggleSorting(column.getIsSorted() === "asc")}
+          >
+            İsim
+            <ArrowUpDown className="ml-2 size-3.5" />
+          </Button>
+        ),
+        cell: ({ row }) => <span className="font-medium">{row.original.name}</span>,
+      },
+      {
+        accessorKey: "email",
+        header: "Email",
+        cell: ({ row }) =>
+          row.original.email ? (
+            <a
+              href={`mailto:${row.original.email}`}
+              className="text-muted-foreground hover:text-foreground hover:underline"
+            >
+              {row.original.email}
+            </a>
+          ) : (
+            <span className="text-muted-foreground">—</span>
+          ),
+      },
+      {
+        accessorKey: "phone",
+        header: "Telefon",
+        cell: ({ row }) =>
+          row.original.phone ? (
+            <a
+              href={`tel:${row.original.phone}`}
+              className="text-muted-foreground hover:text-foreground hover:underline"
+            >
+              {row.original.phone}
+            </a>
+          ) : (
+            <span className="text-muted-foreground">—</span>
+          ),
+      },
+      {
+        accessorKey: "status",
+        header: "Durum",
+        cell: ({ row }) => (
+          <Badge variant={row.original.status === "active" ? "default" : "secondary"}>
+            {row.original.status === "active" ? "Aktif" : "Pasif"}
+          </Badge>
+        ),
+      },
+      {
+        accessorKey: "createdAt",
+        header: ({ column }) => (
+          <Button
+            variant="ghost"
+            size="sm"
+            className="-ml-3 h-8"
+            onClick={() => column.toggleSorting(column.getIsSorted() === "asc")}
+          >
+            Eklendi
+            <ArrowUpDown className="ml-2 size-3.5" />
+          </Button>
+        ),
+        cell: ({ row }) => (
+          <span className="text-muted-foreground text-sm">
+            {new Date(row.original.createdAt).toLocaleDateString("tr-TR", {
+              day: "2-digit",
+              month: "short",
+              year: "numeric",
+            })}
+          </span>
+        ),
+      },
+      {
+        id: "actions",
+        cell: ({ row }) => (
+          <div className="flex justify-end">
+            <DropdownMenu>
+              <DropdownMenuTrigger asChild>
+                <Button variant="ghost" size="icon" className="size-8">
+                  <MoreHorizontal className="size-4" />
+                </Button>
+              </DropdownMenuTrigger>
+              <DropdownMenuContent align="end">
+                <DropdownMenuItem
+                  onClick={() => {
+                    setEditing(row.original);
+                    setFormOpen(true);
+                  }}
+                >
+                  <Pencil className="size-3.5" />
+                  Düzenle
+                </DropdownMenuItem>
+                <DropdownMenuItem
+                  variant="destructive"
+                  onClick={() => setDeleting(row.original)}
+                >
+                  <Trash2 className="size-3.5" />
+                  Sil
+                </DropdownMenuItem>
+              </DropdownMenuContent>
+            </DropdownMenu>
+          </div>
+        ),
+      },
+    ],
+    [],
+  );
+
+  const table = useReactTable({
+    data: customers,
+    columns,
+    state: { globalFilter, sorting },
+    onGlobalFilterChange: setGlobalFilter,
+    onSortingChange: setSorting,
+    getCoreRowModel: getCoreRowModel(),
+    getFilteredRowModel: getFilteredRowModel(),
+    getSortedRowModel: getSortedRowModel(),
+    getPaginationRowModel: getPaginationRowModel(),
+    initialState: { pagination: { pageSize: 20 } },
+    globalFilterFn: (row, _id, filterValue) => {
+      const v = String(filterValue).toLowerCase();
+      return [row.original.name, row.original.email, row.original.phone, row.original.taxId]
+        .join(" ")
+        .toLowerCase()
+        .includes(v);
+    },
+  });
+
+  return (
+    <Card>
+      <CardContent className="p-0">
+        <div className="flex flex-col gap-3 p-4 md:flex-row md:items-center md:justify-between">
+          <div className="relative md:max-w-xs md:flex-1">
+            <Search className="text-muted-foreground absolute top-1/2 left-3 size-4 -translate-y-1/2" />
+            <Input
+              value={globalFilter}
+              onChange={(e) => setGlobalFilter(e.target.value)}
+              placeholder="İsim, email, telefon, vergi no..."
+              className="pl-9"
+            />
+          </div>
+          <Button
+            onClick={() => {
+              setEditing(null);
+              setFormOpen(true);
+            }}
+          >
+            <Plus className="size-4" />
+            Yeni müşteri
+          </Button>
+        </div>
+
+        <Table>
+          <TableHeader>
+            {table.getHeaderGroups().map((headerGroup) => (
+              <TableRow key={headerGroup.id}>
+                {headerGroup.headers.map((header) => (
+                  <TableHead key={header.id}>
+                    {header.isPlaceholder
+                      ? null
+                      : flexRender(header.column.columnDef.header, header.getContext())}
+                  </TableHead>
+                ))}
+              </TableRow>
+            ))}
+          </TableHeader>
+          <TableBody>
+            {table.getRowModel().rows.length ? (
+              table.getRowModel().rows.map((row) => (
+                <TableRow key={row.id}>
+                  {row.getVisibleCells().map((cell) => (
+                    <TableCell key={cell.id}>
+                      {flexRender(cell.column.columnDef.cell, cell.getContext())}
+                    </TableCell>
+                  ))}
+                </TableRow>
+              ))
+            ) : (
+              <TableRow>
+                <TableCell colSpan={columns.length} className="h-32 text-center">
+                  <div className="text-muted-foreground flex flex-col items-center gap-2">
+                    <UserPlus className="size-6" />
+                    <p className="text-sm">Henüz müşteri eklenmemiş.</p>
+                    <Button
+                      variant="outline"
+                      size="sm"
+                      onClick={() => {
+                        setEditing(null);
+                        setFormOpen(true);
+                      }}
+                    >
+                      <Plus className="size-3.5" />
+                      İlk müşteriyi ekle
+                    </Button>
+                  </div>
+                </TableCell>
+              </TableRow>
+            )}
+          </TableBody>
+        </Table>
+
+        <div className="flex items-center justify-between border-t px-4 py-3">
+          <p className="text-muted-foreground text-sm">
+            Toplam {table.getFilteredRowModel().rows.length} müşteri
+          </p>
+          <div className="flex items-center gap-2">
+            <Button
+              variant="outline"
+              size="icon"
+              className="size-8"
+              onClick={() => table.previousPage()}
+              disabled={!table.getCanPreviousPage()}
+            >
+              <ChevronLeft className="size-4" />
+            </Button>
+            <span className="text-muted-foreground text-sm">
+              Sayfa {table.getState().pagination.pageIndex + 1} /{" "}
+              {Math.max(table.getPageCount(), 1)}
+            </span>
+            <Button
+              variant="outline"
+              size="icon"
+              className="size-8"
+              onClick={() => table.nextPage()}
+              disabled={!table.getCanNextPage()}
+            >
+              <ChevronRight className="size-4" />
+            </Button>
+          </div>
+        </div>
+      </CardContent>
+
+      <CustomerFormSheet
+        open={formOpen}
+        onOpenChange={(v) => {
+          setFormOpen(v);
+          if (!v) setEditing(null);
+        }}
+        customer={editing}
+      />
+
+      <DeleteCustomerDialog
+        open={Boolean(deleting)}
+        onOpenChange={(v) => !v && setDeleting(null)}
+        id={deleting?.id ?? null}
+        name={deleting?.name ?? ""}
+      />
+    </Card>
+  );
+}
diff --git a/src/app/(dashboard)/customers/components/delete-customer-dialog.tsx b/src/app/(dashboard)/customers/components/delete-customer-dialog.tsx
new file mode 100644
index 0000000..f3be8cf
--- /dev/null
+++ b/src/app/(dashboard)/customers/components/delete-customer-dialog.tsx
@@ -0,0 +1,76 @@
+"use client";
+
+import { useTransition } from "react";
+import { Loader2, Trash2 } from "lucide-react";
+import { toast } from "sonner";
+
+import { Button } from "@/components/ui/button";
+import {
+  Dialog,
+  DialogContent,
+  DialogDescription,
+  DialogFooter,
+  DialogHeader,
+  DialogTitle,
+} from "@/components/ui/dialog";
+import { deleteCustomerAction } from "@/lib/appwrite/customer-actions";
+
+export function DeleteCustomerDialog({
+  open,
+  onOpenChange,
+  id,
+  name,
+}: {
+  open: boolean;
+  onOpenChange: (v: boolean) => void;
+  id: string | null;
+  name: string;
+}) {
+  const [isPending, startTransition] = useTransition();
+
+  const handleDelete = () => {
+    if (!id) return;
+    startTransition(async () => {
+      const fd = new FormData();
+      fd.set("id", id);
+      const result = await deleteCustomerAction(fd);
+      if (result.ok) {
+        toast.success("Müşteri silindi.");
+        onOpenChange(false);
+      } else {
+        toast.error(result.error ?? "Silme başarısız.");
+      }
+    });
+  };
+
+  return (
+    <Dialog open={open} onOpenChange={onOpenChange}>
+      <DialogContent>
+        <DialogHeader>
+          <DialogTitle>Müşteriyi sil</DialogTitle>
+          <DialogDescription>
+            <strong>{name}</strong> kalıcı olarak silinecek. Bu işlem geri alınamaz.
+          </DialogDescription>
+        </DialogHeader>
+        <DialogFooter>
+          <Button variant="outline" onClick={() => onOpenChange(false)} disabled={isPending}>
+            Vazgeç
+          </Button>
+          <Button variant="destructive" onClick={handleDelete} disabled={isPending}>
+            {isPending ? (
+              <>
+                <Loader2 className="size-4 animate-spin" />
+                Siliniyor...
+              </>
+            ) : (
+              <>
+                <Trash2 className="size-4" />
+                Sil
+              </>
+            )}
+          </Button>
+        </DialogFooter>
+      </DialogContent>
+    </Dialog>
+  );
+}
diff --git a/src/app/(dashboard)/customers/components/types.ts b/src/app/(dashboard)/customers/components/types.ts
new file mode 100644
index 0000000..e9ba12f
--- /dev/null
+++ b/src/app/(dashboard)/customers/components/types.ts
@@ -0,0 +1,11 @@
+export type CustomerRow = {
+  id: string;
+  name: string;
+  email: string;
+  phone: string;
+  taxId: string;
+  address: string;
+  notes: string;
+  status: "active" | "passive";
+  createdAt: string;
+};
diff --git a/src/app/(dashboard)/customers/page.tsx b/src/app/(dashboard)/customers/page.tsx
new file mode 100644
index 0000000..f164fec
--- /dev/null
+++ b/src/app/(dashboard)/customers/page.tsx
@@ -0,0 +1,47 @@
+import type { Metadata } from "next";
+import { redirect } from "next/navigation";
+
+import { listCustomers } from "@/lib/appwrite/customer-queries";
+import { requireTenant } from "@/lib/appwrite/tenant-guard";
+import { CustomersClient } from "./components/customers-client";
+
+export const metadata: Metadata = {
+  title: "İşletmem — Müşteriler",
+};
+
+export default async function CustomersPage() {
+  let ctx;
+  try {
+    ctx = await requireTenant();
+  } catch {
+    redirect("/onboarding");
+  }
+
+  const customers = await listCustomers(ctx.tenantId);
+
+  return (
+    <div className="flex-1 space-y-6 px-6 pt-0">
+      <div className="flex flex-col gap-1">
+        <p className="text-muted-foreground text-sm">{ctx.settings?.companyName ?? "Çalışma alanı"}</p>
+        <h1 className="text-2xl font-bold tracking-tight">Müşteriler</h1>
+        <p className="text-muted-foreground text-sm">
+          Müşterilerinizi yönetin, hizmet ve yazılım ilişkilerini buradan kurun.
+        </p>
+      </div>
+
+      <CustomersClient
+        customers={customers.map((c) => ({
+          id: c.$id,
+          name: c.name,
+          email: c.email ?? "",
+          phone: c.phone ?? "",
+          taxId: c.taxId ?? "",
+          address: c.address ?? "",
+          notes: c.notes ?? "",
+          status: (c.status ?? "active") as "active" | "passive",
+          createdAt: c.$createdAt,
+        }))}
+      />
+    </div>
+  );
+}
diff --git a/src/app/layout.tsx b/src/app/layout.tsx
index 8668160..00ee6fe 100644
--- a/src/app/layout.tsx
+++ b/src/app/layout.tsx
@@ -2,12 +2,13 @@ import type { Metadata } from "next";
 import "./globals.css";
 
 import { ThemeProvider } from "@/components/theme-provider";
+import { Toaster } from "@/components/ui/sonner";
 import { SidebarConfigProvider } from "@/contexts/sidebar-context";
 import { inter } from "@/lib/fonts";
 
 export const metadata: Metadata = {
-  title: "Shadcn Dashboard",
-  description: "A dashboard built with Next.js and shadcn/ui",
+  title: "İşletmem KovakCRM",
+  description: "Multi-tenant CRM — KovakSoft",
 };
 
 export default function RootLayout({
@@ -16,13 +17,12 @@ export default function RootLayout({
   children: React.ReactNode;
 }) {
   return (
-    <html lang="en" className={`${inter.variable} antialiased`}>
+    <html lang="tr" className={`${inter.variable} antialiased`}>
       <body className={inter.className}>
-        <ThemeProvider defaultTheme="system" storageKey="nextjs-ui-theme">
-          <SidebarConfigProvider>
-            {children}
-          </SidebarConfigProvider>
+        <ThemeProvider defaultTheme="system" storageKey="isletmem-ui-theme">
+          <SidebarConfigProvider>{children}</SidebarConfigProvider>
         </ThemeProvider>
+        <Toaster richColors closeButton />
       </body>
     </html>
   );
diff --git a/src/lib/appwrite/customer-actions.ts b/src/lib/appwrite/customer-actions.ts
new file mode 100644
index 0000000..f009bcb
--- /dev/null
+++ b/src/lib/appwrite/customer-actions.ts
@@ -0,0 +1,185 @@
+"use server";
+
+import { revalidatePath } from "next/cache";
+import { AppwriteException, ID, Permission, Role } from "node-appwrite";
+import { z } from "zod";
+
+import { logAudit } from "./audit";
+import { DATABASE_ID, TABLES, type Customer } from "./schema";
+import { createAdminClient } from "./server";
+import { requireTenant } from "./tenant-guard";
+import type { CustomerActionState } from "./customer-types";
+import { customerSchema } from "@/lib/validation/customers";
+
+function appwriteError(e: unknown): string {
+  if (e instanceof AppwriteException) {
+    return e.message || "Beklenmeyen bir hata oluştu.";
+  }
+  return "Bağlantı hatası. Tekrar deneyin.";
+}
+
+function pickFormFields(formData: FormData) {
+  return {
+    name: String(formData.get("name") ?? "").trim(),
+    email: String(formData.get("email") ?? "").trim(),
+    phone: String(formData.get("phone") ?? "").trim(),
+    taxId: String(formData.get("taxId") ?? "").trim(),
+    address: String(formData.get("address") ?? "").trim(),
+    notes: String(formData.get("notes") ?? "").trim(),
+    status: (formData.get("status") as "active" | "passive" | null) ?? "active",
+  };
+}
+
+function flattenErrors(err: z.ZodError): Record<string, string> {
+  const out: Record<string, string> = {};
+  for (const issue of err.issues) {
+    const key = issue.path.join(".");
+    if (key && !out[key]) out[key] = issue.message;
+  }
+  return out;
+}
+
+function teamRowPermissions(tenantId: string) {
+  return [
+    Permission.read(Role.team(tenantId)),
+    Permission.update(Role.team(tenantId)),
+    Permission.delete(Role.team(tenantId, "owner")),
+    Permission.delete(Role.team(tenantId, "admin")),
+  ];
+}
+
+export async function createCustomerAction(
+  _prev: CustomerActionState,
+  formData: FormData,
+): Promise<CustomerActionState> {
+  let ctx;
+  try {
+    ctx = await requireTenant();
+  } catch {
+    return { ok: false, error: "Yetkiniz yok." };
+  }
+
+  const parsed = customerSchema.safeParse(pickFormFields(formData));
+  if (!parsed.success) {
+    return { ok: false, error: "Form geçersiz.", fieldErrors: flattenErrors(parsed.error) };
+  }
+
+  try {
+    const { tablesDB } = createAdminClient();
+    const row = await tablesDB.createRow(
+      DATABASE_ID,
+      TABLES.customers,
+      ID.unique(),
+      {
+        tenantId: ctx.tenantId,
+        createdBy: ctx.user.id,
+        ...parsed.data,
+      },
+      teamRowPermissions(ctx.tenantId),
+    );
+
+    await logAudit({
+      tenantId: ctx.tenantId,
+      userId: ctx.user.id,
+      action: "create",
+      entityType: "customer",
+      entityId: row.$id,
+      changes: parsed.data,
+    });
+  } catch (e) {
+    return { ok: false, error: appwriteError(e) };
+  }
+
+  revalidatePath("/customers");
+  return { ok: true };
+}
+
+export async function updateCustomerAction(
+  _prev: CustomerActionState,
+  formData: FormData,
+): Promise<CustomerActionState> {
+  const id = String(formData.get("id") ?? "");
+  if (!id) return { ok: false, error: "ID eksik." };
+
+  let ctx;
+  try {
+    ctx = await requireTenant();
+  } catch {
+    return { ok: false, error: "Yetkiniz yok." };
+  }
+
+  const parsed = customerSchema.safeParse(pickFormFields(formData));
+  if (!parsed.success) {
+    return { ok: false, error: "Form geçersiz.", fieldErrors: flattenErrors(parsed.error) };
+  }
+
+  try {
+    const { tablesDB } = createAdminClient();
+    const existing = (await tablesDB.getRow(
+      DATABASE_ID,
+      TABLES.customers,
+      id,
+    )) as unknown as Customer;
+
+    if (existing.tenantId !== ctx.tenantId) {
+      return { ok: false, error: "Erişim engellendi." };
+    }
+
+    await tablesDB.updateRow(DATABASE_ID, TABLES.customers, id, parsed.data);
+
+    await logAudit({
+      tenantId: ctx.tenantId,
+      userId: ctx.user.id,
+      action: "update",
+      entityType: "customer",
+      entityId: id,
+      changes: parsed.data,
+    });
+  } catch (e) {
+    return { ok: false, error: appwriteError(e) };
+  }
+
+  revalidatePath("/customers");
+  return { ok: true };
+}
+
+export async function deleteCustomerAction(formData: FormData): Promise<CustomerActionState> {
+  const id = String(formData.get("id") ?? "");
+  if (!id) return { ok: false, error: "ID eksik." };
+
+  let ctx;
+  try {
+    ctx = await requireTenant();
+  } catch {
+    return { ok: false, error: "Yetkiniz yok." };
+  }
+
+  try {
+    const { tablesDB } = createAdminClient();
+    const existing = (await tablesDB.getRow(
+      DATABASE_ID,
+      TABLES.customers,
+      id,
+    )) as unknown as Customer;
+
+    if (existing.tenantId !== ctx.tenantId) {
+      return { ok: false, error: "Erişim engellendi." };
+    }
+
+    await tablesDB.deleteRow(DATABASE_ID, TABLES.customers, id);
+
+    await logAudit({
+      tenantId: ctx.tenantId,
+      userId: ctx.user.id,
+      action: "delete",
+      entityType: "customer",
+      entityId: id,
+      changes: { name: existing.name },
+    });
+  } catch (e) {
+    return { ok: false, error: appwriteError(e) };
+  }
+
+  revalidatePath("/customers");
+  return { ok: true };
+}
diff --git a/src/lib/appwrite/customer-queries.ts b/src/lib/appwrite/customer-queries.ts
new file mode 100644
index 0000000..28e7f01
--- /dev/null
+++ b/src/lib/appwrite/customer-queries.ts
@@ -0,0 +1,42 @@
+import "server-only";
+
+import { Query } from "node-appwrite";
+
+import { createAdminClient } from "./server";
+import { DATABASE_ID, TABLES, type Customer } from "./schema";
+
+export async function listCustomers(tenantId: string): Promise<Customer[]> {
+  try {
+    const { tablesDB } = createAdminClient();
+    const result = await tablesDB.listRows({
+      databaseId: DATABASE_ID,
+      tableId: TABLES.customers,
+      queries: [
+        Query.equal("tenantId", tenantId),
+        Query.orderDesc("$createdAt"),
+        Query.limit(500),
+      ],
+    });
+    return result.rows as unknown as Customer[];
+  } catch {
+    return [];
+  }
+}
+
+export async function getCustomer(
+  tenantId: string,
+  id: string,
+): Promise<Customer | null> {
+  try {
+    const { tablesDB } = createAdminClient();
+    const row = (await tablesDB.getRow(
+      DATABASE_ID,
+      TABLES.customers,
+      id,
+    )) as unknown as Customer;
+    if (row.tenantId !== tenantId) return null;
+    return row;
+  } catch {
+    return null;
+  }
+}
diff --git a/src/lib/appwrite/customer-types.ts b/src/lib/appwrite/customer-types.ts
new file mode 100644
index 0000000..5ce5189
--- /dev/null
+++ b/src/lib/appwrite/customer-types.ts
@@ -0,0 +1,7 @@
+export type CustomerActionState = {
+  ok: boolean;
+  error?: string;
+  fieldErrors?: Record<string, string>;
+};
+
+export const initialCustomerState: CustomerActionState = { ok: false };
diff --git a/src/lib/validation/customers.ts b/src/lib/validation/customers.ts
new file mode 100644
index 0000000..5483ebb
--- /dev/null
+++ b/src/lib/validation/customers.ts
@@ -0,0 +1,16 @@
+import { z } from "zod";
+
+export const customerSchema = z.object({
+  name: z.string().trim().min(1, "İsim zorunlu.").max(255),
+  email: z
+    .union([z.string().email("Geçerli bir email girin."), z.literal("")])
+    .optional()
+    .transform((v) => (v ? v : undefined)),
+  phone: z.string().trim().max(30).optional().transform((v) => (v ? v : undefined)),
+  taxId: z.string().trim().max(50).optional().transform((v) => (v ? v : undefined)),
+  address: z.string().trim().max(500).optional().transform((v) => (v ? v : undefined)),
+  notes: z.string().trim().max(2000).optional().transform((v) => (v ? v : undefined)),
+  status: z.enum(["active", "passive"]).optional().default("active"),
+});
+
+export type CustomerInput = z.infer<typeof customerSchema>;