diff --git a/app/api/payments/create/route.ts b/app/api/payments/create/route.ts
new file mode 100644
index 0000000..7dd354e
--- /dev/null
+++ b/app/api/payments/create/route.ts
@@ -0,0 +1,145 @@
+import { NextRequest, NextResponse } from "next/server";
+import { getPb } from "../../../lib/pb";
+
+const BATCHES = "JEI_payment_batches";
+const INVOICES = "JEI_invoices";
+const ALLOWED_MIME = new Set(["application/pdf", "image/jpeg", "image/png"]);
+const MAX_POP_BYTES = 8 * 1024 * 1024;
+
+export const dynamic = "force-dynamic";
+
+export async function POST(req: NextRequest) {
+  const pb = getPb();
+  let form: FormData;
+  try {
+    form = await req.formData();
+  } catch (e: any) {
+    return NextResponse.json({ error: `Invalid form-data: ${e?.message || e}` }, { status: 400 });
+  }
+
+  const batchRef = String(form.get("batch_ref") || "").trim();
+  const paymentDate = String(form.get("payment_date") || "").trim();
+  const invoiceIdsRaw = String(form.get("invoice_ids") || "");
+  const popFile = form.get("pop_file");
+
+  // 1. invoice_ids
+  let invoiceIds: string[];
+  try {
+    const parsed = JSON.parse(invoiceIdsRaw);
+    if (!Array.isArray(parsed) || parsed.length === 0 || !parsed.every((x) => typeof x === "string")) {
+      throw new Error("invoice_ids must be a non-empty JSON array of strings");
+    }
+    invoiceIds = parsed;
+  } catch (e: any) {
+    return NextResponse.json({ error: e?.message || "Invalid invoice_ids" }, { status: 400 });
+  }
+
+  // 2. batch_ref
+  if (!/^[A-Za-z0-9_-]{1,50}$/.test(batchRef)) {
+    return NextResponse.json(
+      { error: "batch_ref must match ^[A-Za-z0-9_-]{1,50}$" },
+      { status: 400 },
+    );
+  }
+
+  // 3. payment_date
+  if (!/^\d{4}-\d{2}-\d{2}$/.test(paymentDate)) {
+    return NextResponse.json(
+      { error: "payment_date must be YYYY-MM-DD" },
+      { status: 400 },
+    );
+  }
+
+  // 4. pop_file
+  if (!(popFile instanceof File)) {
+    return NextResponse.json({ error: "pop_file is required" }, { status: 400 });
+  }
+  if (!ALLOWED_MIME.has(popFile.type)) {
+    return NextResponse.json(
+      { error: `pop_file type must be PDF, JPG or PNG (got ${popFile.type})` },
+      { status: 400 },
+    );
+  }
+  if (popFile.size > MAX_POP_BYTES) {
+    return NextResponse.json(
+      { error: `pop_file exceeds 8 MB (got ${popFile.size} bytes)` },
+      { status: 400 },
+    );
+  }
+
+  // 5. batch_ref uniqueness
+  try {
+    const dupe = await pb.collection(BATCHES).getList(1, 1, {
+      filter: `batch_ref="${batchRef.replace(/"/g, '\\"')}"`,
+    });
+    if (dupe.totalItems > 0) {
+      return NextResponse.json(
+        { error: `Batch ref "${batchRef}" already exists` },
+        { status: 409 },
+      );
+    }
+  } catch (e: any) {
+    return NextResponse.json(
+      { error: `batch_ref uniqueness check failed: ${e?.message || e}` },
+      { status: 500 },
+    );
+  }
+
+  // 6. Re-validate each invoice is still unpaid
+  const conflicts: string[] = [];
+  const validIds: string[] = [];
+  for (const id of invoiceIds) {
+    try {
+      const inv = await pb.collection(INVOICES).getOne(id);
+      if (inv.payment_batch && inv.payment_batch !== "") {
+        conflicts.push(id);
+      } else {
+        validIds.push(id);
+      }
+    } catch (e: any) {
+      conflicts.push(id); // missing or 404 → treat as conflict
+    }
+  }
+  if (conflicts.length > 0) {
+    return NextResponse.json(
+      { error: `These invoices are already paid or missing: ${conflicts.join(", ")}` },
+      { status: 409 },
+    );
+  }
+
+  // 7. Create the batch
+  let batchId: string;
+  try {
+    const created = await pb.collection(BATCHES).create({
+      batch_ref: batchRef,
+      payment_date: paymentDate,
+      pop_file: popFile,
+    });
+    batchId = created.id;
+  } catch (e: any) {
+    return NextResponse.json(
+      { error: `Failed to create batch: ${e?.message || e}` },
+      { status: 500 },
+    );
+  }
+
+  // 8. PATCH each invoice (best-effort, parallel)
+  const patchErrors: string[] = [];
+  await Promise.all(
+    validIds.map(async (id) => {
+      try {
+        await pb.collection(INVOICES).update(id, { payment_batch: batchId });
+      } catch (e: any) {
+        patchErrors.push(`${id}: ${e?.message || e}`);
+      }
+    }),
+  );
+
+  return NextResponse.json({
+    ok: true,
+    batchId,
+    batchRef,
+    invoiceCount: validIds.length,
+    patchErrors: patchErrors.length > 0 ? patchErrors : undefined,
+  });
+}