diff --git a/apps/edr-freight-api/src/modules/bookings/booking-wagon-cancellation.service.ts b/apps/edr-freight-api/src/modules/bookings/booking-wagon-cancellation.service.ts
index 64ccb1929..86b9dedc6 100644
--- a/apps/edr-freight-api/src/modules/bookings/booking-wagon-cancellation.service.ts
+++ b/apps/edr-freight-api/src/modules/bookings/booking-wagon-cancellation.service.ts
@@ -1875,9 +1875,12 @@ export class BookingWagonCancellationService {
           // the same cargo); number/seal/VGM come from the override when given.
           units: sized.map((u, i) => ({
             containerNumber: replacement?.[i]?.containerNumber ?? u.containerNumber,
+            // A credit snapshot taken before seals were mandatory can carry
+            // none; the booking service normalizes the blank back to null
+            // rather than blocking the rebook of already-paid cargo.
             sealNumber: replacement
-              ? (replacement[i]?.sealNumber ?? undefined)
-              : (u.sealNumber ?? undefined),
+              ? (replacement[i]?.sealNumber ?? '')
+              : (u.sealNumber ?? ''),
             vgmTons: replacement?.[i]?.vgmTons ?? u.vgmTons,
             isHazardous: u.isHazardous,
             isReefer: u.isReefer,
diff --git a/apps/edr-freight-api/src/modules/contracts/contract-booking.service.ts b/apps/edr-freight-api/src/modules/contracts/contract-booking.service.ts
index f5e00f503..88a2175b9 100644
--- a/apps/edr-freight-api/src/modules/contracts/contract-booking.service.ts
+++ b/apps/edr-freight-api/src/modules/contracts/contract-booking.service.ts
@@ -2250,7 +2250,9 @@ export class ContractBookingService {
           unitRepo.create({
             bookingContainerId: containerRow.id,
             containerNumber: unit.containerNumber,
-            sealNumber: unit.sealNumber ?? null,
+            // Legacy units recovered by the remainder placement can still
+            // arrive sealless — keep those null rather than empty-string.
+            sealNumber: unit.sealNumber?.trim() || null,
             vgmTons: unit.vgmTons,
             isHazardous: unit.isHazardous ?? false,
             isReefer: unit.isReefer ?? false,
diff --git a/apps/edr-freight-api/src/modules/contracts/dto/create-booking-under-contract.dto.ts b/apps/edr-freight-api/src/modules/contracts/dto/create-booking-under-contract.dto.ts
index 0592dafc4..b1dabfa16 100644
--- a/apps/edr-freight-api/src/modules/contracts/dto/create-booking-under-contract.dto.ts
+++ b/apps/edr-freight-api/src/modules/contracts/dto/create-booking-under-contract.dto.ts
@@ -7,6 +7,7 @@ import {
   IsEmail,
   IsIn,
   IsInt,
+  IsNotEmpty,
   IsNumber,
   IsOptional,
   IsString,
@@ -32,10 +33,12 @@ export class CreateContainerUnitDto {
   })
   containerNumber!: string;
 
-  @ApiPropertyOptional()
-  @IsOptional()
+  @ApiProperty({ description: 'Seal number — required on every container, import and export alike.' })
   @IsString()
-  sealNumber?: string;
+  @Transform(({ value }) => (typeof value === 'string' ? value.trim() : value))
+  @IsNotEmpty({ message: 'sealNumber is required' })
+  @MaxLength(64)
+  sealNumber!: string;
 
   @ApiProperty({ description: 'VGM in tons', minimum: 0 })
   @IsNumber()
diff --git a/apps/edr-freight-api/src/modules/train-scheduling/remainder-placement.service.ts b/apps/edr-freight-api/src/modules/train-scheduling/remainder-placement.service.ts
index 85b6d0878..e95cb4fe8 100644
--- a/apps/edr-freight-api/src/modules/train-scheduling/remainder-placement.service.ts
+++ b/apps/edr-freight-api/src/modules/train-scheduling/remainder-placement.service.ts
@@ -333,7 +333,9 @@ export class RemainderPlacementService {
 
     return deferred.map((u) => ({
       containerNumber: u.containerNumber,
-      sealNumber: u.sealNumber ?? undefined,
+      // Deferred units predate the seal requirement; the booking service
+      // normalizes the blank back to null rather than rejecting the re-book.
+      sealNumber: u.sealNumber ?? '',
       vgmTons: Number(u.vgmTons),
       isHazardous: u.isHazardous,
       isReefer: u.isReefer,
diff --git a/apps/edr-freight-api/src/modules/warehouses/warehouse-inventory.service.ts b/apps/edr-freight-api/src/modules/warehouses/warehouse-inventory.service.ts
index a2313a8df..aa032c17d 100644
--- a/apps/edr-freight-api/src/modules/warehouses/warehouse-inventory.service.ts
+++ b/apps/edr-freight-api/src/modules/warehouses/warehouse-inventory.service.ts
@@ -3140,6 +3140,13 @@ export class WarehouseInventoryService {
 
       const { warehouse, yard, zone } = await this.validateLocation(manager, dto);
 
+      // Taking a box out of a stack is physically impossible while others stand
+      // on top of it — the same rule the release path enforces. Moving is one of
+      // those exits, so it is checked here rather than only at release.
+      if (item.slotId) {
+        await this.placement.assertAccessible(item.id, manager);
+      }
+
       // A move that names a slot is validated against the hierarchy it claims;
       // one that does not clears the old slot, because the box has left it.
       if (dto.slotId) {
diff --git a/apps/edr-freight-web/backoffice/src/components/contracts/GlCreateBookingForm.tsx b/apps/edr-freight-web/backoffice/src/components/contracts/GlCreateBookingForm.tsx
index eaa399f03..86641c7be 100644
--- a/apps/edr-freight-web/backoffice/src/components/contracts/GlCreateBookingForm.tsx
+++ b/apps/edr-freight-web/backoffice/src/components/contracts/GlCreateBookingForm.tsx
@@ -118,6 +118,7 @@ const blockNegative = (event: KeyboardEvent<HTMLInputElement>) => {
 
 interface UnitErrors {
   containerNumber?: string;
+  sealNumber?: string;
   vgmTons?: string;
 }
 
@@ -886,6 +887,9 @@ export default function GlCreateBookingForm() {
         } else if ((numberCounts.get(key) ?? 0) > 1) {
           errs.containerNumber = "Duplicate container number in this shipment.";
         }
+        if (u.sealNumber.trim() === "") {
+          errs.sealNumber = "Seal number is required.";
+        }
         const vgm = Number(u.vgmTons);
         if (u.vgmTons.trim() === "" || Number.isNaN(vgm) || vgm <= 0) {
           errs.vgmTons = "Enter a valid VGM.";
@@ -1185,7 +1189,7 @@ export default function GlCreateBookingForm() {
             : {}),
           units: l.units.map((u) => ({
             containerNumber: u.containerNumber.trim().toUpperCase(),
-            ...(u.sealNumber ? { sealNumber: u.sealNumber } : {}),
+            sealNumber: u.sealNumber.trim(),
             vgmTons: Number(u.vgmTons) || 0,
             // Per-container handling — the server rolls these into the line
             // counts and bills each surcharge on the ticked containers only.
@@ -1247,7 +1251,7 @@ export default function GlCreateBookingForm() {
           reeferQuantity: Number(l.reeferQuantity || 0) || undefined,
           units: l.units.map((u) => ({
             containerNumber: u.containerNumber.trim().toUpperCase(),
-            ...(u.sealNumber ? { sealNumber: u.sealNumber } : {}),
+            sealNumber: u.sealNumber.trim(),
             vgmTons: Number(u.vgmTons) || 0,
             isHazardous: Boolean(u.isHazardous),
             isReefer: Boolean(u.isReefer),
@@ -1857,7 +1861,7 @@ export default function GlCreateBookingForm() {
                             Container number *
                           </Text>
                           <Text fz={12} fw={600} c="#10202F" style={{ flex: 1 }}>
-                            Seal number
+                            Seal number *
                           </Text>
                           <Text fz={12} fw={600} c="#10202F" style={{ flex: 1 }}>
                             VGM (tons) *
@@ -1901,8 +1905,13 @@ export default function GlCreateBookingForm() {
                             style={{ flex: 1 }}
                           />
                           <TextInput
-                            placeholder="Optional"
+                            placeholder="e.g. SL-0099231"
                             value={unit.sealNumber}
+                            error={
+                              showErrors
+                                ? unitErrors[lineIdx]?.[unitIdx]?.sealNumber
+                                : undefined
+                            }
                             onChange={(e) =>
                               patchUnit(lineIdx, unitIdx, {
                                 sealNumber: e.currentTarget.value,
diff --git a/apps/edr-freight-web/backoffice/src/components/contracts/gl-booking-form/container-excel.ts b/apps/edr-freight-web/backoffice/src/components/contracts/gl-booking-form/container-excel.ts
index c00091bfc..fd34bd967 100644
--- a/apps/edr-freight-web/backoffice/src/components/contracts/gl-booking-form/container-excel.ts
+++ b/apps/edr-freight-web/backoffice/src/components/contracts/gl-booking-form/container-excel.ts
@@ -151,6 +151,11 @@ export async function parseContainerExcel(
       numberCounts.set(containerNumber, (numberCounts.get(containerNumber) ?? 0) + 1);
     }
 
+    const sealNumber = cell("sealNumber");
+    if (!sealNumber) {
+      errors.push(`Row ${rowNo}: seal number is required.`);
+    }
+
     const vgmRaw = cell("vgmTons");
     const vgm = Number(vgmRaw);
     if (!vgmRaw || Number.isNaN(vgm) || vgm <= 0) {
@@ -160,7 +165,7 @@ export async function parseContainerExcel(
     rows.push({
       containerSize: size ?? "",
       containerNumber,
-      sealNumber: cell("sealNumber"),
+      sealNumber,
       vgmTons: vgmRaw,
       hazardous: opts.includeHazardous && parseFlag(cell("hazardous")),
       reefer: opts.includeReefer && parseFlag(cell("reefer")),
diff --git a/apps/edr-freight-web/backoffice/src/components/warehouses/MoveInventoryModal.tsx b/apps/edr-freight-web/backoffice/src/components/warehouses/MoveInventoryModal.tsx
index 1ec596ffe..b7de47ef9 100644
--- a/apps/edr-freight-web/backoffice/src/components/warehouses/MoveInventoryModal.tsx
+++ b/apps/edr-freight-web/backoffice/src/components/warehouses/MoveInventoryModal.tsx
@@ -1,5 +1,6 @@
 import { useEffect, useMemo, useState } from 'react';
-import { Button, Group, Modal, Select, Stack, Textarea } from '@mantine/core';
+import { Alert, Button, Group, List, Modal, Select, Stack, Textarea, Text } from '@mantine/core';
+import { Layers } from 'lucide-react';
 
 import { useMutation, useQuery } from '@tanstack/react-query';
 
@@ -7,6 +8,7 @@ import { api } from '@/services/api';
 import { useToast } from '@/hooks/use-toast';
 import type { WarehouseInventoryItem } from '@/types/warehouse';
 import { extractErrorMessage } from './options';
+import { SlotPicker } from './SlotPicker';
 
 interface MoveInventoryModalProps {
   opened: boolean;
@@ -20,6 +22,7 @@ export function MoveInventoryModal({ opened, onClose, item }: MoveInventoryModal
   const [warehouseId, setWarehouseId] = useState('');
   const [yardId, setYardId] = useState('');
   const [zoneId, setZoneId] = useState('');
+  const [slotId, setSlotId] = useState('');
   const [remarks, setRemarks] = useState('');
 
   useEffect(() => {
@@ -27,10 +30,22 @@ export function MoveInventoryModal({ opened, onClose, item }: MoveInventoryModal
       setWarehouseId('');
       setYardId('');
       setZoneId('');
+      setSlotId('');
       setRemarks('');
     }
   }, [opened]);
 
+  // A container with boxes stacked on top of it cannot be lifted out — the API
+  // refuses the move, so the button says why instead of firing a 409.
+  const accessibilityQuery = useQuery(
+    api.warehouses.containerAccessibility.queryOptions({
+      input: { id: item?.id ?? '' },
+      enabled: opened && Boolean(item?.id),
+    }),
+  );
+  const accessibility = accessibilityQuery.data;
+  const blocked = accessibility ? !accessibility.accessible : false;
+
   const warehousesQuery = useQuery(
     api.warehouses.list.queryOptions({ input: { filter: { status: 'ACTIVE' } } }),
   );
@@ -69,7 +84,13 @@ export function MoveInventoryModal({ opened, onClose, item }: MoveInventoryModal
     try {
       await moveMutation.mutateAsync({
         id: item.id,
-        payload: { warehouseId, yardId, zoneId, remarks: remarks.trim() || undefined },
+        payload: {
+          warehouseId,
+          yardId,
+          zoneId,
+          slotId: slotId || undefined,
+          remarks: remarks.trim() || undefined,
+        },
       });
       toast({ title: 'Inventory moved' });
       onClose();
@@ -81,6 +102,22 @@ export function MoveInventoryModal({ opened, onClose, item }: MoveInventoryModal
   return (
     <Modal opened={opened} onClose={onClose} title="Move inventory" centered size="lg">
       <Stack gap="md">
+        {blocked && accessibility ? (
+          <Alert icon={<Layers size={16} />} color="orange" variant="light" title="Container is buried">
+            <Text size="sm">
+              It sits at {accessibility.stackCode} level {accessibility.level} with{' '}
+              {accessibility.blockingContainers.length} container(s) stacked on top. Move these out
+              first:
+            </Text>
+            <List size="sm" mt={4}>
+              {accessibility.blockingContainers.map((b) => (
+                <List.Item key={b.inventoryId}>
+                  {b.containerNumber ?? 'Container'} — level {b.level}
+                </List.Item>
+              ))}
+            </List>
+          </Alert>
+        ) : null}
         <Select
           label="Destination warehouse"
           placeholder="Select warehouse"
@@ -115,8 +152,13 @@ export function MoveInventoryModal({ opened, onClose, item }: MoveInventoryModal
           disabled={!yardId}
           data={zoneOptions}
           value={zoneId || null}
-          onChange={(v) => setZoneId(v ?? '')}
+          onChange={(v) => {
+            setZoneId(v ?? '');
+            setSlotId('');
+          }}
         />
+        {/* Container yards only — the picker hides itself where no stacks exist. */}
+        <SlotPicker zoneId={zoneId} value={slotId} onChange={setSlotId} label="Destination stack position" />
         <Textarea
           label="Remarks"
           placeholder="Reason for the move"
@@ -129,7 +171,12 @@ export function MoveInventoryModal({ opened, onClose, item }: MoveInventoryModal
           <Button variant="default" onClick={onClose} disabled={moveMutation.isPending}>
             Cancel
           </Button>
-          <Button onClick={handleSubmit} loading={moveMutation.isPending}>
+          <Button
+            onClick={handleSubmit}
+            loading={moveMutation.isPending}
+            disabled={blocked}
+            title={blocked ? 'Containers stacked above this one must be moved first' : undefined}
+          >
             Move inventory
           </Button>
         </Group>
diff --git a/apps/edr-freight-web/backoffice/src/components/warehouses/SlotPicker.tsx b/apps/edr-freight-web/backoffice/src/components/warehouses/SlotPicker.tsx
new file mode 100644
index 000000000..e30444277
--- /dev/null
+++ b/apps/edr-freight-web/backoffice/src/components/warehouses/SlotPicker.tsx
@@ -0,0 +1,87 @@
+import { useMemo } from 'react';
+import { Select, Text } from '@mantine/core';
+import { useQuery } from '@tanstack/react-query';
+
+import { api } from '@/services/api';
+import type { ZoneLayout } from '@/types/warehouse';
+
+interface SlotPickerProps {
+  zoneId: string;
+  value: string;
+  onChange: (slotId: string) => void;
+  label?: string;
+  disabled?: boolean;
+}
+
+/**
+ * The stack levels a container may actually be put on right now.
+ *
+ * Only the next fillable level of each stack is offered: a box cannot stand on
+ * level 2 while level 1 is empty, so listing level 3 of an empty stack would
+ * only produce a rejected request. The server enforces the same rule — this
+ * mirrors it so the operator never sees a 400 for a position the form offered.
+ */
+export function fillableLevels(layout: ZoneLayout | undefined) {
+  if (!layout) return [];
+
+  return layout.stacks
+    .filter((stack) => stack.isActive && stack.status === 'ACTIVE')
+    .flatMap((stack) => {
+      const occupied = stack.slots
+        .filter((slot) => slot.effectiveStatus === 'OCCUPIED')
+        .map((slot) => slot.level);
+      const top = occupied.length > 0 ? Math.max(...occupied) : 0;
+      if (top >= stack.maxStackHeight) return [];
+
+      const next = stack.slots.find(
+        (slot) => slot.level === top + 1 && slot.effectiveStatus === 'AVAILABLE',
+      );
+      if (!next) return [];
+
+      return [
+        {
+          value: next.slotId,
+          label: `${stack.code} — level ${next.level}${top > 0 ? ` (on ${top} container${top > 1 ? 's' : ''})` : ' (ground)'}`,
+        },
+      ];
+    });
+}
+
+export function SlotPicker({ zoneId, value, onChange, label = 'Stack position', disabled }: SlotPickerProps) {
+  const { data, isLoading } = useQuery(
+    api.warehouses.zoneLayout.queryOptions({
+      input: { zoneId },
+      enabled: Boolean(zoneId),
+    }),
+  );
+
+  const options = useMemo(() => fillableLevels(data), [data]);
+
+  // A zone with no stacks configured keeps plain zone-level placement — showing
+  // an empty picker there would imply a choice that does not exist.
+  if (!zoneId || (!isLoading && (data?.stacks.length ?? 0) === 0)) return null;
+
+  return (
+    <Select
+      label={label}
+      description={
+        options.length === 0 && !isLoading ? (
+          <Text size="xs" c="orange">
+            Every stack in this zone is full or blocked — the item will be stored at zone level.
+          </Text>
+        ) : (
+          'Leave blank to take the lowest free level automatically.'
+        )
+      }
+      placeholder={isLoading ? 'Loading positions…' : 'Automatic (lowest free level)'}
+      searchable
+      clearable
+      disabled={disabled || isLoading || options.length === 0}
+      data={options}
+      value={value || null}
+      onChange={(v) => onChange(v ?? '')}
+    />
+  );
+}
+
+export default SlotPicker;
diff --git a/apps/edr-freight-web/backoffice/src/components/warehouses/StoreInventoryModal.tsx b/apps/edr-freight-web/backoffice/src/components/warehouses/StoreInventoryModal.tsx
index f1a5aa4ad..c9051dba6 100644
--- a/apps/edr-freight-web/backoffice/src/components/warehouses/StoreInventoryModal.tsx
+++ b/apps/edr-freight-web/backoffice/src/components/warehouses/StoreInventoryModal.tsx
@@ -8,6 +8,7 @@ import { api } from '@/services/api';
 import { useToast } from '@/hooks/use-toast';
 import type { WarehouseInventoryItem } from '@/types/warehouse';
 import { extractErrorMessage } from './options';
+import { SlotPicker } from './SlotPicker';
 
 interface StoreInventoryModalProps {
   opened: boolean;
@@ -25,12 +26,14 @@ export function StoreInventoryModal({ opened, onClose, item }: StoreInventoryMod
   const [warehouseId, setWarehouseId] = useState('');
   const [yardId, setYardId] = useState('');
   const [zoneId, setZoneId] = useState('');
+  const [slotId, setSlotId] = useState('');
 
   useEffect(() => {
     if (opened) {
       setWarehouseId('');
       setYardId('');
       setZoneId('');
+      setSlotId('');
     }
   }, [opened]);
 
@@ -75,7 +78,7 @@ export function StoreInventoryModal({ opened, onClose, item }: StoreInventoryMod
     try {
       await storeMutation.mutateAsync({
         id: item.id,
-        payload: manualComplete ? { warehouseId, yardId, zoneId } : undefined,
+        payload: manualComplete ? { warehouseId, yardId, zoneId, slotId: slotId || undefined } : undefined,
       });
       toast({ title: manualComplete ? 'Inventory stored at selected location' : 'Inventory stored (auto-allocated)' });
       onClose();
@@ -127,8 +130,13 @@ export function StoreInventoryModal({ opened, onClose, item }: StoreInventoryMod
           disabled={!yardId}
           data={zoneOptions}
           value={zoneId || null}
-          onChange={(v) => setZoneId(v ?? '')}
+          onChange={(v) => {
+            setZoneId(v ?? '');
+            setSlotId('');
+          }}
         />
+        {/* Container yards only — the picker hides itself where no stacks exist. */}
+        <SlotPicker zoneId={zoneId} value={slotId} onChange={setSlotId} />
         <Group justify="flex-end" mt="sm">
           <Button variant="default" onClick={onClose} disabled={storeMutation.isPending}>
             Cancel
diff --git a/apps/edr-freight-web/backoffice/src/components/warehouses/ZoneLayoutModal.tsx b/apps/edr-freight-web/backoffice/src/components/warehouses/ZoneLayoutModal.tsx
new file mode 100644
index 000000000..7821ee1b3
--- /dev/null
+++ b/apps/edr-freight-web/backoffice/src/components/warehouses/ZoneLayoutModal.tsx
@@ -0,0 +1,407 @@
+import { useMemo, useState } from 'react';
+import {
+  ActionIcon,
+  Badge,
+  Button,
+  Card,
+  Group,
+  Loader,
+  Menu,
+  Modal,
+  NumberInput,
+  Paper,
+  SimpleGrid,
+  Stack,
+  Text,
+  TextInput,
+  Tooltip,
+} from '@mantine/core';
+import { useMutation, useQuery } from '@tanstack/react-query';
+import { Ban, CircleSlash, Layers, MoreVertical, Plus, Trash2, Unlock } from 'lucide-react';
+
+import { useAuth } from '@/auth/useAuth';
+import { useToast } from '@/hooks/use-toast';
+import { FREIGHT_PERMS, hasPermission } from '@/lib/permissions';
+import { api } from '@/services/api';
+import type { SlotEffectiveStatus, ZoneLayoutSlot, ZoneLayoutStack } from '@/types/warehouse';
+import { extractErrorMessage } from './options';
+import type { ZoneRef } from './ZoneContentsModal';
+
+interface ZoneLayoutModalProps {
+  opened: boolean;
+  onClose: () => void;
+  zone: ZoneRef | null;
+}
+
+/** One colour per slot state, used by both the cell and the legend. */
+const SLOT_TONE: Record<SlotEffectiveStatus, { color: string; label: string }> = {
+  OCCUPIED: { color: 'blue', label: 'Occupied' },
+  AVAILABLE: { color: 'teal', label: 'Free' },
+  RESERVED: { color: 'orange', label: 'Reserved' },
+  BLOCKED: { color: 'red', label: 'Blocked' },
+  INACTIVE: { color: 'gray', label: 'Inactive' },
+};
+
+/**
+ * A container stack seen from the side: level 3 on top, level 1 on the ground —
+ * the order the API already returns and the order the yard actually looks.
+ */
+function SlotCell({
+  slot,
+  onSetStatus,
+  canEdit,
+}: {
+  slot: ZoneLayoutSlot;
+  canEdit: boolean;
+  onSetStatus: (slot: ZoneLayoutSlot, status: 'AVAILABLE' | 'BLOCKED' | 'RESERVED') => void;
+}) {
+  const tone = SLOT_TONE[slot.effectiveStatus];
+  const occupied = slot.effectiveStatus === 'OCCUPIED';
+
+  return (
+    <Paper
+      withBorder
+      radius="sm"
+      px="xs"
+      py={6}
+      style={{ borderLeft: `4px solid var(--mantine-color-${tone.color}-6)` }}
+    >
+      <Group justify="space-between" wrap="nowrap" gap="xs">
+        <Group gap={6} wrap="nowrap" style={{ minWidth: 0 }}>
+          <Text size="xs" c="dimmed" fw={600} w={20}>
+            L{slot.level}
+          </Text>
+          <Text size="sm" truncate title={slot.containerNumber ?? tone.label}>
+            {occupied ? (slot.containerNumber ?? 'Container') : tone.label}
+          </Text>
+        </Group>
+
+        {/* An occupied level has no status to set — empty it by moving the box. */}
+        {canEdit && !occupied ? (
+          <Menu position="bottom-end" withinPortal>
+            <Menu.Target>
+              <ActionIcon variant="subtle" size="sm" aria-label={`Level ${slot.level} actions`}>
+                <MoreVertical size={14} />
+              </ActionIcon>
+            </Menu.Target>
+            <Menu.Dropdown>
+              <Menu.Item
+                leftSection={<Unlock size={14} />}
+                disabled={slot.effectiveStatus === 'AVAILABLE'}
+                onClick={() => onSetStatus(slot, 'AVAILABLE')}
+              >
+                Mark free
+              </Menu.Item>
+              <Menu.Item
+                leftSection={<CircleSlash size={14} />}
+                disabled={slot.effectiveStatus === 'RESERVED'}
+                onClick={() => onSetStatus(slot, 'RESERVED')}
+              >
+                Reserve
+              </Menu.Item>
+              <Menu.Item
+                leftSection={<Ban size={14} />}
+                color="red"
+                disabled={slot.effectiveStatus === 'BLOCKED'}
+                onClick={() => onSetStatus(slot, 'BLOCKED')}
+              >
+                Block
+              </Menu.Item>
+            </Menu.Dropdown>
+          </Menu>
+        ) : null}
+      </Group>
+    </Paper>
+  );
+}
+
+function StackCard({
+  stack,
+  canEdit,
+  canDelete,
+  onSetSlotStatus,
+  onDelete,
+}: {
+  stack: ZoneLayoutStack;
+  canEdit: boolean;
+  canDelete: boolean;
+  onSetSlotStatus: (slot: ZoneLayoutSlot, status: 'AVAILABLE' | 'BLOCKED' | 'RESERVED') => void;
+  onDelete: (stack: ZoneLayoutStack) => void;
+}) {
+  const filled = stack.slots.filter((s) => s.effectiveStatus === 'OCCUPIED').length;
+
+  return (
+    <Card withBorder radius="md" padding="sm">
+      <Stack gap={8}>
+        <Group justify="space-between" wrap="nowrap" gap="xs">
+          <Group gap={6} wrap="nowrap" style={{ minWidth: 0 }}>
+            <Text fw={600} size="sm" truncate title={stack.name ?? stack.code}>
+              {stack.code}
+            </Text>
+            {stack.status !== 'ACTIVE' || !stack.isActive ? (
+              <Badge size="xs" color="gray" variant="light">
+                Inactive
+              </Badge>
+            ) : null}
+          </Group>
+          <Group gap={4} wrap="nowrap">
+            <Badge size="sm" variant="light" color={filled === stack.maxStackHeight ? 'blue' : 'gray'}>
+              {filled}/{stack.maxStackHeight}
+            </Badge>
+            {canDelete ? (
+              <Tooltip label="Delete stack">
+                <ActionIcon
+                  variant="subtle"
+                  color="red"
+                  size="sm"
+                  onClick={() => onDelete(stack)}
+                  aria-label={`Delete stack ${stack.code}`}
+                >
+                  <Trash2 size={14} />
+                </ActionIcon>
+              </Tooltip>
+            ) : null}
+          </Group>
+        </Group>
+
+        <Stack gap={4}>
+          {stack.slots.map((slot) => (
+            <SlotCell key={slot.slotId} slot={slot} canEdit={canEdit} onSetStatus={onSetSlotStatus} />
+          ))}
+        </Stack>
+      </Stack>
+    </Card>
+  );
+}
+
+/**
+ * Physical layout of one zone — every ground stack with its levels, what stands
+ * on each, and the capacity numbers that are routinely confused (configured vs
+ * built vs full). Stacks are created and retired from here, since there is
+ * nowhere else the yard layout is visible.
+ */
+export function ZoneLayoutModal({ opened, onClose, zone }: ZoneLayoutModalProps) {
+  const { toast } = useToast();
+  const { user } = useAuth();
+  const canCreate = hasPermission(user, FREIGHT_PERMS.warehouseZones.create);
+  const canEdit = hasPermission(user, FREIGHT_PERMS.warehouseZones.update);
+  const canDelete = hasPermission(user, FREIGHT_PERMS.warehouseZones.delete);
+
+  const zoneId = zone?.id ?? '';
+  const { data, isLoading, isError, refetch } = useQuery(
+    api.warehouses.zoneLayout.queryOptions({
+      input: { zoneId },
+      enabled: opened && Boolean(zoneId),
+    }),
+  );
+
+  const [creating, setCreating] = useState(false);
+  const [code, setCode] = useState('');
+  const [height, setHeight] = useState<number>(3);
+
+  const createStack = useMutation(api.warehouses.createStack.mutationOptions());
+  const deleteStack = useMutation(api.warehouses.deleteStack.mutationOptions());
+  const updateSlot = useMutation(api.warehouses.updateSlot.mutationOptions());
+
+  const stacks = data?.stacks ?? [];
+  const summary = data?.summary;
+
+  const nextCode = useMemo(() => {
+    // Suggest the next number in the zone's own series (ZA-001 → ZA-002) so
+    // codes stay sortable, which is the order the placement engine walks.
+    const numbered = stacks
+      .map((s) => /^(.*?)(\d+)$/.exec(s.code))
+      .filter((m): m is RegExpExecArray => Boolean(m));
+    if (numbered.length === 0) return '';
+    const last = numbered[numbered.length - 1];
+    const width = last[2].length;
+    const next = Math.max(...numbered.map((m) => Number(m[2]))) + 1;
+    return `${last[1]}${String(next).padStart(width, '0')}`;
+  }, [stacks]);
+
+  const submitStack = () => {
+    const trimmed = code.trim();
+    if (!trimmed) {
+      toast({ variant: 'destructive', title: 'Stack code is required' });
+      return;
+    }
+    createStack.mutate(
+      { zoneId, payload: { code: trimmed, maxStackHeight: height } },
+      {
+        onSuccess: () => {
+          toast({ title: `Stack ${trimmed} created with ${height} level(s)` });
+          setCode('');
+          setCreating(false);
+        },
+        onError: (error) =>
+          toast({
+            variant: 'destructive',
+            title: 'Could not create the stack',
+            description: extractErrorMessage(error),
+          }),
+      },
+    );
+  };
+
+  const removeStack = (stack: ZoneLayoutStack) => {
+    if (!window.confirm(`Delete stack ${stack.code}? It must be empty first.`)) return;
+    deleteStack.mutate(
+      { id: stack.stackId, zoneId },
+      {
+        onSuccess: () => toast({ title: `Stack ${stack.code} deleted` }),
+        onError: (error) =>
+          toast({
+            variant: 'destructive',
+            title: 'Could not delete the stack',
+            description: extractErrorMessage(error),
+          }),
+      },
+    );
+  };
+
+  const setSlotStatus = (slot: ZoneLayoutSlot, status: 'AVAILABLE' | 'BLOCKED' | 'RESERVED') => {
+    updateSlot.mutate(
+      { slotId: slot.slotId, zoneId, payload: { status, isActive: true } },
+      {
+        onSuccess: () => toast({ title: `Level ${slot.level} set to ${SLOT_TONE[status].label}` }),
+        onError: (error) =>
+          toast({
+            variant: 'destructive',
+            title: 'Could not update the level',
+            description: extractErrorMessage(error),
+          }),
+      },
+    );
+  };
+
+  return (
+    <Modal
+      opened={opened}
+      onClose={onClose}
+      size="xl"
+      title={
+        <Group gap="xs">
+          <Layers size={18} />
+          <Text fw={700}>{zone ? `${zone.name} (${zone.code}) layout` : 'Zone layout'}</Text>
+        </Group>
+      }
+    >
+      <Stack gap="md">
+        {summary ? (
+          <Card withBorder radius="md" padding="sm">
+            <Group gap="lg" wrap="wrap">
+              <Stat label="Configured capacity" value={summary.configuredCapacity ?? '—'} />
+              <Stat label="Slots built" value={summary.physicalSlotCount} />
+              <Stat label="Occupied" value={summary.occupiedSlotCount} color="blue" />
+              <Stat label="Free" value={summary.availableSlotCount} color="teal" />
+              <Stat label="Reserved" value={summary.reservedSlotCount} color="orange" />
+              <Stat label="Blocked" value={summary.blockedSlotCount} color="red" />
+            </Group>
+            {summary.inconsistent ? (
+              <Text size="xs" c="red" mt={6}>
+                {summary.physicalSlotCount} slots are built but the zone is configured for{' '}
+                {summary.configuredCapacity}. Raise the zone capacity or remove stacks — the
+                configured figure was left as it is.
+              </Text>
+            ) : null}
+          </Card>
+        ) : null}
+
+        <Group justify="space-between">
+          <Group gap="xs">
+            {(Object.keys(SLOT_TONE) as SlotEffectiveStatus[]).map((key) => (
+              <Badge key={key} size="xs" variant="light" color={SLOT_TONE[key].color}>
+                {SLOT_TONE[key].label}
+              </Badge>
+            ))}
+          </Group>
+          {canCreate ? (
+            <Button
+              size="xs"
+              leftSection={<Plus size={14} />}
+              variant={creating ? 'default' : 'filled'}
+              onClick={() => {
+                setCreating((open) => !open);
+                if (!creating && !code) setCode(nextCode);
+              }}
+            >
+              {creating ? 'Cancel' : 'Add stack'}
+            </Button>
+          ) : null}
+        </Group>
+
+        {creating ? (
+          <Card withBorder radius="md" padding="sm">
+            <Group align="flex-end" gap="sm">
+              <TextInput
+                label="Stack code"
+                placeholder="ZA-001"
+                value={code}
+                onChange={(e) => setCode(e.currentTarget.value)}
+                style={{ flex: 1 }}
+              />
+              <NumberInput
+                label="Levels"
+                description="One slot is created per level"
+                min={1}
+                max={10}
+                value={height}
+                onChange={(v) => setHeight(Number(v) || 1)}
+                w={140}
+              />
+              <Button onClick={submitStack} loading={createStack.isPending}>
+                Create
+              </Button>
+            </Group>
+          </Card>
+        ) : null}
+
+        {isLoading ? (
+          <Group justify="center" py="xl">
+            <Loader />
+          </Group>
+        ) : isError ? (
+          <Stack align="center" py="xl" gap="xs">
+            <Text c="red">Failed to load the zone layout.</Text>
+            <Button variant="default" size="xs" onClick={() => void refetch()}>
+              Retry
+            </Button>
+          </Stack>
+        ) : stacks.length === 0 ? (
+          <Text c="dimmed" ta="center" py="xl" size="sm">
+            No ground stacks configured in this zone yet. Containers stored here keep zone-level
+            placement until stacks exist.
+          </Text>
+        ) : (
+          <SimpleGrid cols={{ base: 1, xs: 2, sm: 3, lg: 4 }} spacing="sm">
+            {stacks.map((stack) => (
+              <StackCard
+                key={stack.stackId}
+                stack={stack}
+                canEdit={canEdit}
+                canDelete={canDelete}
+                onSetSlotStatus={setSlotStatus}
+                onDelete={removeStack}
+              />
+            ))}
+          </SimpleGrid>
+        )}
+      </Stack>
+    </Modal>
+  );
+}
+
+function Stat({ label, value, color }: { label: string; value: number | string; color?: string }) {
+  return (
+    <Stack gap={0}>
+      <Text size="xs" c="dimmed">
+        {label}
+      </Text>
+      <Text fw={700} c={color}>
+        {value}
+      </Text>
+    </Stack>
+  );
+}
+
+export default ZoneLayoutModal;
diff --git a/apps/edr-freight-web/backoffice/src/components/warehouses/index.ts b/apps/edr-freight-web/backoffice/src/components/warehouses/index.ts
index 24d727854..4e0ebd7f8 100644
--- a/apps/edr-freight-web/backoffice/src/components/warehouses/index.ts
+++ b/apps/edr-freight-web/backoffice/src/components/warehouses/index.ts
@@ -10,6 +10,8 @@ export { CreateWarehouseModal } from './CreateWarehouseModal';
 export { CreateYardModal } from './CreateYardModal';
 export { CreateZoneModal } from './CreateZoneModal';
 export { ZoneContentsModal, type ZoneRef } from './ZoneContentsModal';
+export { ZoneLayoutModal } from './ZoneLayoutModal';
+export { SlotPicker } from './SlotPicker';
 export { ReceiveInventoryModal, WarehouseFlowWorkbench } from './ReceiveInventoryModal';
 export { WarehouseInfoCard } from './WarehouseInfoCard';
 export { MoveInventoryModal } from './MoveInventoryModal';
diff --git a/apps/edr-freight-web/backoffice/src/components/warehouses/slot-picker.test.ts b/apps/edr-freight-web/backoffice/src/components/warehouses/slot-picker.test.ts
new file mode 100644
index 000000000..ea2cbd984
--- /dev/null
+++ b/apps/edr-freight-web/backoffice/src/components/warehouses/slot-picker.test.ts
@@ -0,0 +1,97 @@
+import { describe, expect, it } from 'vitest';
+
+import { fillableLevels } from './SlotPicker';
+import type { SlotEffectiveStatus, ZoneLayout } from '@/types/warehouse';
+
+/**
+ * The picker must offer only positions the API will accept, or the operator
+ * gets a 400 for a level the form itself suggested.
+ */
+function layout(
+  stacks: Array<{
+    code: string;
+    height?: number;
+    isActive?: boolean;
+    levels: SlotEffectiveStatus[];
+  }>,
+): ZoneLayout {
+  return {
+    zoneId: 'zone-1',
+    zoneCode: 'L1-O-A-ZA',
+    zoneName: 'Zone A',
+    summary: {
+      configuredCapacity: 60,
+      physicalSlotCount: 60,
+      occupiedSlotCount: 0,
+      reservedSlotCount: 0,
+      blockedSlotCount: 0,
+      inactiveSlotCount: 0,
+      availableSlotCount: 60,
+      inconsistent: false,
+    },
+    stacks: stacks.map((stack) => ({
+      stackId: `id-${stack.code}`,
+      code: stack.code,
+      name: null,
+      maxStackHeight: stack.height ?? 3,
+      status: stack.isActive === false ? 'INACTIVE' : 'ACTIVE',
+      isActive: stack.isActive !== false,
+      // The API returns the highest level first — mirror that here.
+      slots: stack.levels
+        .map((effectiveStatus, index) => ({
+          slotId: `${stack.code}-L${index + 1}`,
+          level: index + 1,
+          effectiveStatus,
+          inventoryId: effectiveStatus === 'OCCUPIED' ? `inv-${stack.code}-${index + 1}` : null,
+          containerNumber: null,
+        }))
+        .reverse(),
+    })),
+  };
+}
+
+describe('SlotPicker.fillableLevels', () => {
+  it('offers the ground level of an empty stack', () => {
+    const options = fillableLevels(layout([{ code: 'ZA-001', levels: ['AVAILABLE', 'AVAILABLE', 'AVAILABLE'] }]));
+    expect(options).toEqual([{ value: 'ZA-001-L1', label: 'ZA-001 — level 1 (ground)' }]);
+  });
+
+  it('offers only the level directly above the top container', () => {
+    const options = fillableLevels(layout([{ code: 'ZA-001', levels: ['OCCUPIED', 'AVAILABLE', 'AVAILABLE'] }]));
+    expect(options).toEqual([{ value: 'ZA-001-L2', label: 'ZA-001 — level 2 (on 1 container)' }]);
+  });
+
+  it('never offers a level that would float over an empty one', () => {
+    const options = fillableLevels(layout([{ code: 'ZA-001', levels: ['OCCUPIED', 'OCCUPIED', 'AVAILABLE'] }]));
+    expect(options.map((o) => o.value)).toEqual(['ZA-001-L3']);
+  });
+
+  it('drops a full stack', () => {
+    expect(fillableLevels(layout([{ code: 'ZA-001', levels: ['OCCUPIED', 'OCCUPIED', 'OCCUPIED'] }]))).toEqual([]);
+  });
+
+  it('drops a stack whose next level is blocked or reserved', () => {
+    expect(fillableLevels(layout([{ code: 'ZA-001', levels: ['BLOCKED', 'AVAILABLE', 'AVAILABLE'] }]))).toEqual([]);
+    expect(fillableLevels(layout([{ code: 'ZA-002', levels: ['RESERVED', 'AVAILABLE', 'AVAILABLE'] }]))).toEqual([]);
+  });
+
+  it('drops an inactive stack', () => {
+    expect(
+      fillableLevels(layout([{ code: 'ZA-001', isActive: false, levels: ['AVAILABLE', 'AVAILABLE', 'AVAILABLE'] }])),
+    ).toEqual([]);
+  });
+
+  it('lists one position per stack across the zone', () => {
+    const options = fillableLevels(
+      layout([
+        { code: 'ZA-001', levels: ['OCCUPIED', 'AVAILABLE', 'AVAILABLE'] },
+        { code: 'ZA-002', levels: ['AVAILABLE', 'AVAILABLE', 'AVAILABLE'] },
+      ]),
+    );
+    expect(options.map((o) => o.value)).toEqual(['ZA-001-L2', 'ZA-002-L1']);
+  });
+
+  it('returns nothing before the layout has loaded', () => {
+    expect(fillableLevels(undefined)).toEqual([]);
+  });
+});
diff --git a/apps/edr-freight-web/backoffice/src/constants/URLS.ts b/apps/edr-freight-web/backoffice/src/constants/URLS.ts
index f56e4b90d..32eb6b798 100644
--- a/apps/edr-freight-web/backoffice/src/constants/URLS.ts
+++ b/apps/edr-freight-web/backoffice/src/constants/URLS.ts
@@ -652,6 +652,16 @@ export const URL_CONSTANTS = {
   WAREHOUSE_ZONES: {
     BASE: "/warehouse-zones",
     BY_ID: (id: string) => `/warehouse-zones/${id}`,
+    LAYOUT: (id: string) => `/warehouse-zones/${id}/layout`,
+    SLOT_SUMMARY: (id: string) => `/warehouse-zones/${id}/slot-summary`,
+  },
+
+  WAREHOUSE_ZONE_STACKS: {
+    BASE: "/warehouse-zone-stacks",
+    BY_ZONE: (zoneId: string) => `/warehouse-zone-stacks?zoneId=${zoneId}`,
+    BY_ID: (id: string) => `/warehouse-zone-stacks/${id}`,
+    OCCUPANCY: (id: string) => `/warehouse-zone-stacks/${id}/occupancy`,
+    SLOT: (slotId: string) => `/warehouse-zone-stacks/slots/${slotId}`,
   },
 
   WAREHOUSE_INVENTORY: {
@@ -666,6 +676,10 @@ export const URL_CONSTANTS = {
     LOAD: (id: string) => `/warehouse-inventory/${id}/load`,
     DISPATCH: (id: string) => `/warehouse-inventory/${id}/dispatch`,
     MOVE: (id: string) => `/warehouse-inventory/${id}/move`,
+    FIND_SLOT: "/warehouse-inventory/placement/find-slot",
+    ASSIGN_SLOT: (id: string) => `/warehouse-inventory/${id}/assign-slot`,
+    RELEASE_SLOT: (id: string) => `/warehouse-inventory/${id}/release-slot`,
+    ACCESSIBILITY: (id: string) => `/warehouse-inventory/${id}/accessibility`,
     RESERVE: "/warehouse-inventory/reserve",
     ARRIVAL_QUEUE: "/warehouse-inventory/arrival-queue",
     OPS_STATS: "/warehouse-inventory/ops-stats",
diff --git a/apps/edr-freight-web/backoffice/src/pages/warehouses/WarehouseDetailPage.tsx b/apps/edr-freight-web/backoffice/src/pages/warehouses/WarehouseDetailPage.tsx
index fa4b786de..2ea0b64d2 100644
--- a/apps/edr-freight-web/backoffice/src/pages/warehouses/WarehouseDetailPage.tsx
+++ b/apps/edr-freight-web/backoffice/src/pages/warehouses/WarehouseDetailPage.tsx
@@ -12,7 +12,7 @@ import {
   Tabs,
   Text,
 } from '@mantine/core';
-import { ArrowLeft, Boxes, LayoutGrid, Package, Pencil, Plus, Trash2 } from 'lucide-react';
+import { ArrowLeft, Boxes, Layers, LayoutGrid, Package, Pencil, Plus, Trash2 } from 'lucide-react';
 import { useMutation, useQuery } from '@tanstack/react-query';
 import { DataTable, type ColumnDef } from '@edr/ui-common';
 
@@ -25,6 +25,7 @@ import {
   WarehouseTypeBadge,
   ZoneContentsModal,
   type ZoneRef,
+  ZoneLayoutModal,
   ZoneOccupancyHeatmap,
   formatCapacity,
   humanizeEnum,
@@ -63,6 +64,7 @@ export default function WarehouseDetailPage() {
   const [editingZone, setEditingZone] = useState<WarehouseZone | null>(null);
   const [selectedYardId, setSelectedYardId] = useState<string | null>(null);
   const [contentsZone, setContentsZone] = useState<ZoneRef | null>(null);
+  const [layoutZone, setLayoutZone] = useState<ZoneRef | null>(null);
 
   const zonesQuery = useQuery(
     api.warehouses.listZones.queryOptions({
@@ -203,6 +205,14 @@ export default function WarehouseDetailPage() {
         meta: { headerClassName: 'text-right', cellClassName: 'text-right' },
         cell: ({ row }) => (
           <Group gap={4} justify="flex-end" wrap="nowrap" onClick={(e) => e.stopPropagation()}>
+            <ActionIcon
+              variant="subtle"
+              color="gray"
+              title="Stack layout"
+              onClick={() => setLayoutZone(row.original)}
+            >
+              <Layers size={16} />
+            </ActionIcon>
             <ActionIcon
               variant="subtle"
               color="gray"
@@ -425,6 +435,12 @@ export default function WarehouseDetailPage() {
           yard={editingYard}
         />
       )}
+      <ZoneLayoutModal
+        opened={Boolean(layoutZone)}
+        onClose={() => setLayoutZone(null)}
+        zone={layoutZone}
+      />
+
       <ZoneContentsModal
         opened={Boolean(contentsZone)}
         onClose={() => setContentsZone(null)}
diff --git a/apps/edr-freight-web/backoffice/src/services/api.ts b/apps/edr-freight-web/backoffice/src/services/api.ts
index a84615176..855b3805a 100644
--- a/apps/edr-freight-web/backoffice/src/services/api.ts
+++ b/apps/edr-freight-web/backoffice/src/services/api.ts
@@ -154,6 +154,14 @@ import type {
   WarehouseYard,
   WarehouseZone,
   ZoneContentItem,
+  ZoneLayout,
+  ZoneSlotSummary,
+  WarehouseZoneStack,
+  WarehouseZoneSlot,
+  SaveStackPayload,
+  AvailableSlot,
+  ContainerAccessibility,
+  FindSlotPayload,
 } from "@/types/warehouse";
 import { endpoint } from "@/utils/endpoint";
 import {
@@ -1259,6 +1267,85 @@ export const api = {
       ({ zoneId }) => ["warehouse-zones", zoneId, "contents"],
     ),
 
+    zoneLayout: endpoint<{ zoneId: string }, ZoneLayout>(
+      "warehouse-zones",
+      "layout",
+      ({ zoneId }) => warehouseService.zoneLayout(zoneId).then((r) => r.data),
+      ({ zoneId }) => ["warehouse-zones", zoneId, "layout"],
+    ),
+
+    zoneSlotSummary: endpoint<{ zoneId: string }, ZoneSlotSummary>(
+      "warehouse-zones",
+      "slot-summary",
+      ({ zoneId }) => warehouseService.zoneSlotSummary(zoneId).then((r) => r.data),
+      ({ zoneId }) => ["warehouse-zones", zoneId, "slot-summary"],
+    ),
+
+    // ── Ground stacks and slots ────────────────────────────────────────────
+    listStacks: endpoint<{ zoneId: string }, WarehouseZoneStack[]>(
+      "warehouse-zone-stacks",
+      "list",
+      ({ zoneId }) => warehouseService.listStacks(zoneId).then((r) => r.data),
+      ({ zoneId }) => ["warehouse-zone-stacks", zoneId],
+    ),
+
+    createStack: endpoint<
+      { zoneId: string; payload: SaveStackPayload },
+      WarehouseZoneStack
+    >(
+      "warehouse-zone-stacks",
+      "create",
+      ({ zoneId, payload }) =>
+        warehouseService.createStack(zoneId, payload).then((r) => r.data),
+      undefined,
+      ({ zoneId }) => [
+        ["warehouse-zone-stacks", zoneId],
+        ["warehouse-zones", zoneId, "layout"],
+        ["warehouse-zones", zoneId, "slot-summary"],
+      ],
+    ),
+
+    updateStack: endpoint<
+      { id: string; zoneId: string; payload: Partial<SaveStackPayload> },
+      WarehouseZoneStack
+    >(
+      "warehouse-zone-stacks",
+      "update",
+      ({ id, payload }) => warehouseService.updateStack(id, payload).then((r) => r.data),
+      undefined,
+      ({ zoneId }) => [
+        ["warehouse-zone-stacks", zoneId],
+        ["warehouse-zones", zoneId, "layout"],
+        ["warehouse-zones", zoneId, "slot-summary"],
+      ],
+    ),
+
+    deleteStack: endpoint<{ id: string; zoneId: string }, unknown>(
+      "warehouse-zone-stacks",
+      "delete",
+      ({ id }) => warehouseService.removeStack(id).then((r) => r.data),
+      undefined,
+      ({ zoneId }) => [
+        ["warehouse-zone-stacks", zoneId],
+        ["warehouse-zones", zoneId, "layout"],
+        ["warehouse-zones", zoneId, "slot-summary"],
+      ],
+    ),
+
+    updateSlot: endpoint<
+      { slotId: string; zoneId: string; payload: { status?: string; isActive?: boolean } },
+      WarehouseZoneSlot
+    >(
+      "warehouse-zone-stacks",
+      "update-slot",
+      ({ slotId, payload }) => warehouseService.updateSlot(slotId, payload).then((r) => r.data),
+      undefined,
+      ({ zoneId }) => [
+        ["warehouse-zones", zoneId, "layout"],
+        ["warehouse-zones", zoneId, "slot-summary"],
+      ],
+    ),
+
     deleteZone: endpoint<{ id: string }, unknown>(
       "warehouses",
       "deleteZone",
@@ -1490,7 +1577,7 @@ export const api = {
       "store",
       ({ id, payload }) => warehouseService.store(id, payload).then((r) => r.data),
       undefined,
-      () => INVENTORY_INVALIDATIONS,
+      () => [...INVENTORY_INVALIDATIONS, ["warehouse-zones"]],
     ),
 
     reserve: endpoint<ReserveInventoryPayload, WarehouseInventoryItem>(
@@ -1529,6 +1616,36 @@ export const api = {
       () => INVENTORY_INVALIDATIONS,
     ),
 
+    findAvailableSlot: endpoint<FindSlotPayload, AvailableSlot | null>(
+      "warehouse-inventory",
+      "find-slot",
+      (payload) => warehouseService.findAvailableSlot(payload).then((r) => r.data),
+      (payload) => ["warehouse-inventory", "find-slot", payload],
+    ),
+
+    containerAccessibility: endpoint<{ id: string }, ContainerAccessibility>(
+      "warehouse-inventory",
+      "accessibility",
+      ({ id }) => warehouseService.containerAccessibility(id).then((r) => r.data),
+      ({ id }) => ["warehouse-inventory", id, "accessibility"],
+    ),
+
+    assignSlot: endpoint<{ id: string; slotId?: string }, WarehouseInventoryItem>(
+      "warehouse-inventory",
+      "assign-slot",
+      ({ id, slotId }) => warehouseService.assignSlot(id, slotId).then((r) => r.data),
+      undefined,
+      () => [...INVENTORY_INVALIDATIONS, ["warehouse-zones"]],
+    ),
+
+    releaseSlot: endpoint<{ id: string }, WarehouseInventoryItem>(
+      "warehouse-inventory",
+      "release-slot",
+      ({ id }) => warehouseService.releaseSlot(id).then((r) => r.data),
+      undefined,
+      () => [...INVENTORY_INVALIDATIONS, ["warehouse-zones"]],
+    ),
+
     move: endpoint<
       { id: string; payload: MoveInventoryPayload },
       WarehouseInventoryItem
@@ -1538,7 +1655,7 @@ export const api = {
       ({ id, payload }) =>
         warehouseService.move(id, payload).then((r) => r.data),
       undefined,
-      () => INVENTORY_INVALIDATIONS,
+      () => [...INVENTORY_INVALIDATIONS, ["warehouse-zones"]],
     ),
 
     markReadyForPickup: endpoint<string, WarehouseInventoryItem>(
diff --git a/apps/edr-freight-web/backoffice/src/services/warehouse.service.ts b/apps/edr-freight-web/backoffice/src/services/warehouse.service.ts
index f0c894097..ad66776c3 100644
--- a/apps/edr-freight-web/backoffice/src/services/warehouse.service.ts
+++ b/apps/edr-freight-web/backoffice/src/services/warehouse.service.ts
@@ -5,6 +5,14 @@ import { api as apiClient } from '../auth/http';
 import { URL_CONSTANTS } from '@/constants/URLS';
 import type {
   ZoneOccupancy,
+  ZoneLayout,
+  ZoneSlotSummary,
+  WarehouseZoneStack,
+  WarehouseZoneSlot,
+  SaveStackPayload,
+  AvailableSlot,
+  ContainerAccessibility,
+  FindSlotPayload,
   TruckOnSite,
   WarehouseOpsStats,
   WarehouseThroughputPoint,
@@ -289,6 +297,37 @@ export const warehouseService = {
   removeZone: (id: string) => apiClient.delete(URL_CONSTANTS.WAREHOUSE_ZONES.BY_ID(id)),
   zoneContents: (zoneId: string) =>
     apiClient.get<ZoneContentItem[]>(`${URL_CONSTANTS.WAREHOUSE_ZONES.BY_ID(zoneId)}/contents`),
+  zoneLayout: (zoneId: string) =>
+    apiClient.get<ZoneLayout>(URL_CONSTANTS.WAREHOUSE_ZONES.LAYOUT(zoneId)),
+  zoneSlotSummary: (zoneId: string) =>
+    apiClient.get<ZoneSlotSummary>(URL_CONSTANTS.WAREHOUSE_ZONES.SLOT_SUMMARY(zoneId)),
+
+  // ── Ground stacks and slots ────────────────────────────────────────────
+  listStacks: (zoneId: string) =>
+    apiClient.get<WarehouseZoneStack[]>(URL_CONSTANTS.WAREHOUSE_ZONE_STACKS.BY_ZONE(zoneId)),
+  createStack: (zoneId: string, payload: SaveStackPayload) =>
+    apiClient.post<WarehouseZoneStack>(URL_CONSTANTS.WAREHOUSE_ZONE_STACKS.BASE, {
+      ...payload,
+      zoneId,
+    }),
+  updateStack: (id: string, payload: Partial<SaveStackPayload>) =>
+    apiClient.patch<WarehouseZoneStack>(URL_CONSTANTS.WAREHOUSE_ZONE_STACKS.BY_ID(id), payload),
+  removeStack: (id: string) =>
+    apiClient.delete(URL_CONSTANTS.WAREHOUSE_ZONE_STACKS.BY_ID(id)),
+  updateSlot: (slotId: string, payload: { status?: string; isActive?: boolean }) =>
+    apiClient.patch<WarehouseZoneSlot>(URL_CONSTANTS.WAREHOUSE_ZONE_STACKS.SLOT(slotId), payload),
+
+  // ── Physical placement ─────────────────────────────────────────────────
+  findAvailableSlot: (payload: FindSlotPayload) =>
+    apiClient.post<AvailableSlot | null>(URL_CONSTANTS.WAREHOUSE_INVENTORY.FIND_SLOT, payload),
+  assignSlot: (id: string, slotId?: string) =>
+    apiClient.post<WarehouseInventoryItem>(URL_CONSTANTS.WAREHOUSE_INVENTORY.ASSIGN_SLOT(id), {
+      slotId,
+    }),
+  releaseSlot: (id: string) =>
+    apiClient.post<WarehouseInventoryItem>(URL_CONSTANTS.WAREHOUSE_INVENTORY.RELEASE_SLOT(id), {}),
+  containerAccessibility: (id: string) =>
+    apiClient.get<ContainerAccessibility>(URL_CONSTANTS.WAREHOUSE_INVENTORY.ACCESSIBILITY(id)),
 
   // ── Inventory ──────────────────────────────────────────────────────────
   listInventory: (filter?: InventoryFilter) =>
diff --git a/apps/edr-freight-web/backoffice/src/types/warehouse.ts b/apps/edr-freight-web/backoffice/src/types/warehouse.ts
index 90999c5ae..b17b728a9 100644
--- a/apps/edr-freight-web/backoffice/src/types/warehouse.ts
+++ b/apps/edr-freight-web/backoffice/src/types/warehouse.ts
@@ -145,6 +145,122 @@ export interface WarehouseYard {
   zones?: WarehouseZone[];
 }
 
+export const WAREHOUSE_STACK_STATUSES = ['ACTIVE', 'INACTIVE'] as const;
+export type WarehouseStackStatus = (typeof WAREHOUSE_STACK_STATUSES)[number];
+
+/** Stored slot intent. OCCUPIED is never stored — it is derived from inventory. */
+export const WAREHOUSE_SLOT_STATUSES = ['AVAILABLE', 'BLOCKED', 'RESERVED', 'INACTIVE'] as const;
+export type WarehouseSlotStatus = (typeof WAREHOUSE_SLOT_STATUSES)[number];
+
+export type SlotEffectiveStatus = WarehouseSlotStatus | 'OCCUPIED';
+
+/** One vertical level of a ground stack. */
+export interface WarehouseZoneSlot {
+  id: string;
+  stackId: string;
+  level: number;
+  status: WarehouseSlotStatus;
+  isActive: boolean;
+}
+
+/** One ground footprint inside a zone — where containers are stacked vertically. */
+export interface WarehouseZoneStack {
+  id: string;
+  zoneId: string;
+  code: string;
+  name: string | null;
+  row: string | null;
+  bay: string | null;
+  position: string | null;
+  maxStackHeight: number;
+  status: WarehouseStackStatus;
+  isActive: boolean;
+  slots?: WarehouseZoneSlot[];
+}
+
+export interface SaveStackPayload {
+  code: string;
+  name?: string;
+  row?: string;
+  bay?: string;
+  position?: string;
+  maxStackHeight?: number;
+  status?: WarehouseStackStatus;
+}
+
+/** Configured capacity vs slots actually built vs slots actually full. */
+export interface ZoneSlotSummary {
+  configuredCapacity: number | null;
+  physicalSlotCount: number;
+  occupiedSlotCount: number;
+  reservedSlotCount: number;
+  blockedSlotCount: number;
+  inactiveSlotCount: number;
+  availableSlotCount: number;
+  /** True when more slots are built than the configured capacity allows. */
+  inconsistent: boolean;
+}
+
+export interface ZoneLayoutSlot {
+  slotId: string;
+  level: number;
+  effectiveStatus: SlotEffectiveStatus;
+  inventoryId: string | null;
+  containerNumber: string | null;
+}
+
+export interface ZoneLayoutStack {
+  stackId: string;
+  code: string;
+  name: string | null;
+  maxStackHeight: number;
+  status: WarehouseStackStatus;
+  isActive: boolean;
+  /** Highest level first, the way the yard is seen from the side. */
+  slots: ZoneLayoutSlot[];
+}
+
+export interface ZoneLayout {
+  zoneId: string;
+  zoneCode: string;
+  zoneName: string;
+  stacks: ZoneLayoutStack[];
+  summary: ZoneSlotSummary;
+}
+
+export interface FindSlotPayload {
+  yardId: string;
+  zoneId?: string;
+  direction?: 'IMPORT' | 'EXPORT' | 'BOTH';
+  cargoTypeId?: string;
+}
+
+/** The lowest free stack level the placement engine would use next. */
+export interface AvailableSlot {
+  slotId: string;
+  stackId: string;
+  stackCode: string;
+  level: number;
+  zoneId: string;
+  zoneCode: string;
+}
+
+export interface BlockingContainer {
+  inventoryId: string;
+  containerNumber: string | null;
+  level: number;
+  status: string;
+}
+
+/** Whether a container can be lifted out, and what is stacked on top of it. */
+export interface ContainerAccessibility {
+  accessible: boolean;
+  inventoryId: string;
+  stackCode: string | null;
+  level: number | null;
+  blockingContainers: BlockingContainer[];
+}
+
 /** One container (or bulk lot) currently sitting in a zone. */
 export interface ZoneContentItem {
   inventoryId: string;
@@ -382,6 +498,8 @@ export interface MoveInventoryPayload {
   warehouseId: string;
   yardId: string;
   zoneId: string;
+  /** Exact stack level in the destination zone. Container yards only. */
+  slotId?: string;
   remarks?: string;
 }
 
@@ -657,6 +775,8 @@ export interface StoreInventoryPayload {
   warehouseId?: string;
   yardId?: string;
   zoneId?: string;
+  /** Exact stack level. Omit to let the placement engine pick the lowest free one. */
+  slotId?: string;
 }
 
 export interface ImportTrainItem {
@@ -1120,6 +1240,8 @@ export interface MoveInventoryPayload {
   warehouseId: string;
   yardId: string;
   zoneId: string;
+  /** Exact stack level in the destination zone. Container yards only. */
+  slotId?: string;
   remarks?: string;
 }
 
diff --git a/apps/edr-freight-web/portal/src/pages/contracts/NewShipmentPage.tsx b/apps/edr-freight-web/portal/src/pages/contracts/NewShipmentPage.tsx
index 544cc9449..61d162035 100644
--- a/apps/edr-freight-web/portal/src/pages/contracts/NewShipmentPage.tsx
+++ b/apps/edr-freight-web/portal/src/pages/contracts/NewShipmentPage.tsx
@@ -595,7 +595,7 @@ function NewShipmentBookingForm({
                   : {}),
                 units: l.units.map((u) => ({
                   containerNumber: u.containerNumber,
-                  sealNumber: u.sealNumber || undefined,
+                  sealNumber: u.sealNumber.trim(),
                   vgmTons: Number(u.vgmTons),
                   // Per-container handling — the server rolls these up into the
                   // line counts and bills each surcharge on the ticked containers.
@@ -2309,7 +2309,7 @@ function ContainerLineEditor({
               Container number *
             </Text>
             <Text fz={12} fw={600} c="#10202F" style={{ flex: 1 }}>
-              Seal number
+              Seal number *
             </Text>
             <Text fz={12} fw={600} c="#10202F" style={{ flex: 1 }}>
               VGM (tons) *
@@ -2355,10 +2355,11 @@ function ContainerLineEditor({
               <Controller
                 name={`containers.${index}.units.${u}.sealNumber`}
                 control={form.control}
-                render={({ field }) => (
+                render={({ field, fieldState }) => (
                   <TextInput
                     {...field}
-                    placeholder="Optional"
+                    placeholder="e.g. SL-0099231"
+                    error={fieldState.error?.message}
                     radius={10}
                     styles={fieldStyles}
                     style={{ flex: 1 }}
diff --git a/apps/edr-freight-web/portal/src/pages/contracts/new-shipment-form/container-excel.test.ts b/apps/edr-freight-web/portal/src/pages/contracts/new-shipment-form/container-excel.test.ts
new file mode 100644
index 000000000..1c26329f6
--- /dev/null
+++ b/apps/edr-freight-web/portal/src/pages/contracts/new-shipment-form/container-excel.test.ts
@@ -0,0 +1,52 @@
+import { describe, expect, it } from "vitest";
+import * as XLSX from "xlsx";
+
+import { parseContainerExcel } from "./container-excel";
+
+// Seals became mandatory at booking time — a spreadsheet row without one must
+// reject the whole file, the same way a missing VGM already does.
+const OPTS = {
+  allowedSizes: ["20ft", "40ft"],
+  includeHazardous: false,
+  includeReefer: false,
+};
+
+function sheetFile(rows: string[][]): File {
+  const workbook = XLSX.utils.book_new();
+  XLSX.utils.book_append_sheet(
+    workbook,
+    XLSX.utils.aoa_to_sheet([
+      ["Container Size", "Container Number", "Seal Number", "VGM (Tons)"],
+      ...rows,
+    ]),
+    "Containers",
+  );
+  const buffer = XLSX.write(workbook, { type: "array", bookType: "xlsx" });
+  return new File([buffer], "containers.xlsx");
+}
+
+describe("parseContainerExcel", () => {
+  it("accepts a row carrying a seal", async () => {
+    const result = await parseContainerExcel(
+      sheetFile([["40ft", "MSCU1234567", "SL-0099231", "24.5"]]),
+      OPTS,
+    );
+
+    expect(result.errors).toEqual([]);
+    expect(result.rows).toHaveLength(1);
+    expect(result.rows[0].sealNumber).toBe("SL-0099231");
+  });
+
+  it("rejects the file when a row has no seal", async () => {
+    const result = await parseContainerExcel(
+      sheetFile([
+        ["40ft", "MSCU1234567", "SL-0099231", "24.5"],
+        ["20ft", "MSCU7654321", "", "12"],
+      ]),
+      OPTS,
+    );
+
+    expect(result.rows).toEqual([]);
+    expect(result.errors).toContain("Row 3: seal number is required.");
+  });
+});
diff --git a/apps/edr-freight-web/portal/src/pages/contracts/new-shipment-form/container-excel.ts b/apps/edr-freight-web/portal/src/pages/contracts/new-shipment-form/container-excel.ts
index c00091bfc..fd34bd967 100644
--- a/apps/edr-freight-web/portal/src/pages/contracts/new-shipment-form/container-excel.ts
+++ b/apps/edr-freight-web/portal/src/pages/contracts/new-shipment-form/container-excel.ts
@@ -151,6 +151,11 @@ export async function parseContainerExcel(
       numberCounts.set(containerNumber, (numberCounts.get(containerNumber) ?? 0) + 1);
     }
 
+    const sealNumber = cell("sealNumber");
+    if (!sealNumber) {
+      errors.push(`Row ${rowNo}: seal number is required.`);
+    }
+
     const vgmRaw = cell("vgmTons");
     const vgm = Number(vgmRaw);
     if (!vgmRaw || Number.isNaN(vgm) || vgm <= 0) {
@@ -160,7 +165,7 @@ export async function parseContainerExcel(
     rows.push({
       containerSize: size ?? "",
       containerNumber,
-      sealNumber: cell("sealNumber"),
+      sealNumber,
       vgmTons: vgmRaw,
       hazardous: opts.includeHazardous && parseFlag(cell("hazardous")),
       reefer: opts.includeReefer && parseFlag(cell("reefer")),
diff --git a/apps/edr-freight-web/portal/src/pages/contracts/new-shipment-form/schema.ts b/apps/edr-freight-web/portal/src/pages/contracts/new-shipment-form/schema.ts
index 5405347b0..121346d06 100644
--- a/apps/edr-freight-web/portal/src/pages/contracts/new-shipment-form/schema.ts
+++ b/apps/edr-freight-web/portal/src/pages/contracts/new-shipment-form/schema.ts
@@ -61,7 +61,9 @@ const containerUnitSchema = z.object({
       (v) => ISO_CONTAINER_NUMBER_REGEX.test(v.trim().toUpperCase()),
       "Enter a valid ISO container number (e.g. ABCD1234567).",
     ),
-  sealNumber: z.string().default(""),
+  sealNumber: z
+    .string()
+    .refine((v) => v.trim().length > 0, "Seal number is required."),
   vgmTons: z
     .string()
     .refine((v) => v.trim().length > 0, "VGM is required.")