diff --git a/src/api/index.js b/src/api/index.js
index e21f093..7b73a52 100644
--- a/src/api/index.js
+++ b/src/api/index.js
@@ -220,9 +220,9 @@ export const article = {
     return http('/api/article', {
       method: 'POST',
       body: {
-        parentId,
+        parentId: Number(parentId),
         name,
-        ...(track_stock !== undefined ? { track_stock } : {}),
+        ...(track_stock !== undefined ? { track_stock: Boolean(track_stock) } : {}),
       },
     });
   },
@@ -320,7 +320,7 @@ export const article = {
   setBrandIdBySku(sku, brandId) {
     return http(`/api/article/${encodeURIComponent(sku)}/brand`, {
       method: 'PUT',
-      body: { brandId },
+      body: { brandId: brandId != null ? Number(brandId) : null },
     });
   },
 
@@ -363,9 +363,13 @@ export const article = {
    * → 201 { supplier: ArticleSupplier }
    */
   addSupplier(sku, body) {
+    const payload = {
+      ...body,
+      entityId: Number(body?.entityId),
+    };
     return http(`/api/article/${encodeURIComponent(sku)}/supplier`, {
       method: 'POST',
-      body,
+      body: payload,
     });
   },
 
@@ -657,7 +661,7 @@ export const category = {
   create({ parentId, name }) {
     return http('/api/category', {
       method: 'POST',
-      body: { parentId, name },
+      body: { parentId: Number(parentId), name },
     });
   },
 
diff --git a/src/components/manifest/manifestConfig.js b/src/components/manifest/manifestConfig.js
index 90202e6..d376437 100644
--- a/src/components/manifest/manifestConfig.js
+++ b/src/components/manifest/manifestConfig.js
@@ -457,8 +457,14 @@ export async function buildManifestBody(
       lines: buildLines(form.lines, { requireAtLeastOne }),
     };
   }
-  if (form.partyId != null) body[partyField] = form.partyId;
-  else if (!requireAtLeastOne) body[partyField] = null;
+  if (form.partyId != null && form.partyId !== '') {
+    const pid = Number(form.partyId);
+    if (!Number.isNaN(pid)) {
+      body[partyField] = pid;
+    }
+  } else if (!requireAtLeastOne) {
+    body[partyField] = null;
+  }
 
   // Add files if attachments exist
   if (form.attachments && form.attachments.length > 0) {