fix(invoices): force 0% VAT on recurring and bulk-created invoices when the company is not VAT registered (#1838)

Issue #1719: moms lands on an invoice even though momskrysset
(company_settings.vat_registered) is off. The web and v1 create/update
routes, the MCP commit, and the webshop route all zero every line via
buildInvoiceWriteData, but two paths insert invoices directly and never
consult vat_registered:

1. executeRecurringSchedule (cron + run-now): the schedule dialog
   defaults template lines to 25%, stores vat_rate with no gate, and the
   spawn falls back to the customer default (25% for Swedish customers)
   for null-rate lines. The generated invoice carried 25% output VAT and
   could be auto-emailed to the customer and booked against 2611.
2. POST /api/v1/.../invoices/bulk-create: same fallback, same direct
   insert.

Both now mirror buildInvoiceWriteData: when vat_registered is false,
every line is forced to 0% at spawn/create time, and the header lands as
treatment 'exempt' with moms_ruta and reverse_charge_text null.

Self-billed received invoices deliberately keep their stated VAT: the
counterparty issued that document, and the books must mirror it
(ML 16 kap 23 §). Credit notes keep mirroring the invoice they credit.


Claude-Session: https://claude.ai/code/session_01SyDuePXxUFowaPBKpAv8SF

Co-authored-by: Jakob Wennberg <311770904+jakobwennberg-oss@users.noreply.github.com>
Co-authored-by: Claude Fable 5 <noreply@anthropic.com>

app/api/v1/companies/[companyId]/invoices/bulk-create/__tests__/route.test.ts

@@ -331,6 +331,49 @@ describe('POST /api/v1/companies/:companyId/invoices/bulk-create', () => {
     expect(insertedInvoice).toBe(false)
   })
 
+  it('forces every line to 0% when the company is not VAT registered (issue #1719)', async () => {
+    // Momskrysset off (company_settings.vat_registered = false): the invoice
+    // must come out momsfri whether the payload sends an explicit rate or
+    // relies on the customer-default fallback (25% for a Swedish customer).
+    mockServiceClient.mockReturnValue(
+      makeFlexibleSupabase({
+        company_members: { data: { company_id: COMPANY_ID, role: 'owner' }, error: null },
+        customers: { data: VALID_CUSTOMER, error: null },
+        company_settings: { data: { vat_registered: false }, error: null },
+      }),
+    )
+
+    const res = await bulkCreate(
+      makeRequest(`https://x.test/api/v1/companies/${COMPANY_ID}/invoices/bulk-create?dry_run=true`, {
+        invoices: [
+          {
+            customer_id: CUSTOMER_ID,
+            invoice_date: '2026-05-12',
+            due_date: '2026-06-11',
+            currency: 'SEK',
+            items: [
+              { ...SAMPLE_ITEM('Explicit 25'), vat_rate: 25 },
+              SAMPLE_ITEM('Fallback rate'),
+            ],
+          },
+        ],
+      }),
+      companyParams(COMPANY_ID),
+    )
+
+    expect(res.status).toBe(200)
+    const body = await res.json()
+    expect(body.data.preview.summary.succeeded).toBe(1)
+    const preview = body.data.preview.results[0].data.preview
+    expect(preview.subtotal).toBe(2000)
+    expect(preview.vat_amount).toBe(0)
+    expect(preview.total).toBe(2000)
+    for (const item of preview.items) {
+      expect(item.vat_rate).toBe(0)
+      expect(item.vat_amount).toBe(0)
+    }
+  })
+
   it('rejects all_or_nothing: true with 501 NOT_IMPLEMENTED', async () => {
     mockServiceClient.mockReturnValue(
       makeFlexibleSupabase({

app/api/v1/companies/[companyId]/invoices/bulk-create/route.ts

@@ -194,6 +194,21 @@ async function createOneInvoice(
   )
   const allowedRates = new Set(permittedRates.map((r) => r.rate))
 
+  // VAT registration gate, mirroring buildInvoiceWriteData (issue #1719): a
+  // non-momsregistrerad company books no output VAT, so every line is forced
+  // to 0% (momsfri) server-side no matter what the batch payload carries,
+  // explicitly or via the customer-default fallback below. 0% is a permitted
+  // rate for every customer type, so the allowedRates gate still passes.
+  const { data: vatSettings } = await supabase
+    .from('company_settings')
+    .select('vat_registered')
+    .eq('company_id', companyId)
+    .maybeSingle()
+  const notVatRegistered = vatSettings?.vat_registered === false
+  if (notVatRegistered && documentType !== 'delivery_note') {
+    for (const item of input.items) item.vat_rate = 0
+  }
+
   const subtotal = input.items.reduce((sum, item) => sum + item.quantity * item.unit_price, 0)
   let vatAmount = 0
   if (documentType !== 'delivery_note') {
@@ -315,10 +330,13 @@ async function createOneInvoice(
       total,
       total_sek: documentType === 'delivery_note' ? null : totalSek,
       remaining_amount: documentType === 'invoice' ? total : 0,
-      vat_treatment: vatRules.treatment,
+      // Header VAT fields mirror buildInvoiceWriteData: a not-VAT-registered
+      // company stamps the sale as momsfri (treatment 'exempt', no ruta, no
+      // reverse-charge notation); every line rate is already zeroed above.
+      vat_treatment: notVatRegistered ? 'exempt' : vatRules.treatment,
       vat_rate: headerVatRate,
-      moms_ruta: vatRules.momsRuta,
-      reverse_charge_text: vatRules.reverseChargeText || null,
+      moms_ruta: notVatRegistered ? null : vatRules.momsRuta,
+      reverse_charge_text: notVatRegistered ? null : (vatRules.reverseChargeText || null),
       your_reference: input.your_reference,
       our_reference: input.our_reference,
       notes: input.notes,