diff --git a/addons/laundry_management/static/src/js/pos_order_patch.js b/addons/laundry_management/static/src/js/pos_order_patch.js
new file mode 100644
index 0000000..a61a5bc
--- /dev/null
+++ b/addons/laundry_management/static/src/js/pos_order_patch.js
@@ -0,0 +1,133 @@
+/** @odoo-module
+ *
+ * PosOrder patch — laundry context fields.
+ *
+ * Two responsibilities:
+ *   1. setup(): seed primitive defaults on the reactive proxy so that
+ *      OWL components (panel, receipt) which read these slots track
+ *      future writes and re-render. Without seeding, assigning a fresh
+ *      property after first render does NOT trigger reactivity.
+ *      No fields are pulled from the loader — pure in-memory defaults.
+ *
+ *   2. serializeForORM(): inject the laundry slots into the sync_from_ui
+ *      payload so the backend pos.order columns are populated, exactly
+ *      like `general_customer_note`.
+ *      - laundry_order_type_id        → integer id  (Many2one)
+ *      - laundry_order_attribute_ids  → [[6, 0, ids]]  (Many2many "set")
+ *      - laundry_is_delivery          → boolean
+ *      - laundry_delivery_address     → string | false
+ *      - laundry_delivery_scheduled_at → string | false
+ *
+ * NOTE: this patch does NOT touch order.lines, pricing, taxes, or any
+ * relational field exposed by _load_pos_data_fields.
+ */
+import { patch } from "@web/core/utils/patch";
+import { PosOrder } from "@point_of_sale/app/models/pos_order";
+
+function pickId(v) {
+    if (!v) return false;
+    if (typeof v === "number") return v;
+    if (typeof v === "object" && Number.isInteger(v.id)) return v.id;
+    return false;
+}
+
+function pickIds(arr) {
+    if (!Array.isArray(arr)) return [];
+    const out = [];
+    const seen = new Set();
+    for (const v of arr) {
+        const id = pickId(v);
+        if (id && !seen.has(id)) {
+            seen.add(id);
+            out.push(id);
+        }
+    }
+    return out;
+}
+
+function normalizeDateTime(value) {
+    if (!value || typeof value !== "string") return false;
+
+    let v = value;
+
+    // Remove timezone like +03:00 or -03:00
+    const tzMatch = v.match(/([+-]\d{2}:\d{2})$/);
+    if (tzMatch) {
+        v = v.replace(tzMatch[0], "");
+    }
+
+    // Remove Z
+    if (v.endsWith("Z")) {
+        v = v.slice(0, -1);
+    }
+
+    // Remove milliseconds
+    if (v.includes(".")) {
+        v = v.split(".")[0];
+    }
+
+    // Replace T with space
+    v = v.replace("T", " ");
+
+    // Ensure seconds exist
+    if (/^\d{4}-\d{2}-\d{2} \d{2}:\d{2}$/.test(v)) {
+        v += ":00";
+    }
+
+    return v;
+}
+
+patch(PosOrder.prototype, {
+    setup(...args) {
+        super.setup(...args);
+        // Seed defaults on the reactive proxy. Assigning after first
+        // render only triggers OWL reactivity if the key already exists
+        // on the proxy at observation time.
+        if (this.laundry_order_type_id === undefined) {
+            this.laundry_order_type_id = false;
+        }
+        if (this.laundry_order_attribute_ids === undefined) {
+            this.laundry_order_attribute_ids = [];
+        }
+        if (this.laundry_is_delivery === undefined) {
+            this.laundry_is_delivery = false;
+        }
+        if (this.laundry_delivery_address === undefined) {
+            this.laundry_delivery_address = false;
+        }
+        if (this.laundry_delivery_scheduled_at === undefined) {
+            this.laundry_delivery_scheduled_at = false;
+        }
+    },
+
+    initState(...args) {
+        super.initState(...args);
+        // Reactive flag for POS Mode system: when true, the order is a
+        // dedicated settlement context — products cannot be added,
+        // quantities cannot be edited, line cannot be deleted.
+        // Seeded here so OWL reactivity tracks future writes.
+        if (this.uiState && !("is_laundry_settle_due" in this.uiState)) {
+            this.uiState.is_laundry_settle_due = false;
+        }
+    },
+
+    serializeForORM(opts = {}) {
+        const data = super.serializeForORM(opts);
+
+        const typeId = pickId(this.laundry_order_type_id);
+        data.laundry_order_type_id = typeId || false;
+
+        const attrIds = pickIds(this.laundry_order_attribute_ids);
+        data.laundry_order_attribute_ids = [[6, 0, attrIds]];
+
+        data.laundry_is_delivery = !!this.laundry_is_delivery;
+        data.laundry_delivery_address = this.laundry_delivery_address || false;
+        // ABSOLUTE GUARANTEE: nothing with a "T", ".000", or timezone reaches
+        // the backend. Run the full normalizer even if upstream already did;
+        // normalize(normalize(x)) === normalize(x), so this is a zero-cost net.
+        data.laundry_delivery_scheduled_at =
+            normalizeDateTime(this.laundry_delivery_scheduled_at) || false;
+
+        return data;
+    },
+});