Phase 1 — Billing Statement Export (near-term) Sztab already has time tracking (SZ-71). The missing piece is a billing rate per user per project, which is a small schema addition. With that in place, Sztab can generate a monthly billing statement: grouped by calendar month, with hours X rate and subtotals - exportable as PDF or CSV. This is the "copy-paste into your invoicing system" path, and it's buildable quickly.

Phase 2 — Native Invoice Entity (medium-term) Sztab generates and stores invoices directly: line items pulled from time entries, a Draft => Sent => Paid status lifecycle, PDF rendering, and a shareable link. This makes Sztab the source of truth for contractor-to-Tigase billing - which is exactly our use case.

Phase 3 — QBO Sync (longer-term) As discussed separately, a provider-agnostic bookkeeping integration layer (QBO first, extensible to Xero etc.) would push finalized invoices out to the accounting system automatically. No double-entry.

Starting with Phase 1 as a near-term addition: it has immediate practical value and the groundwork is already there.

Implementation notes (Phase 1)

repository layer: monthlyBilling() in TimeEntryRepository does one JPQL query, one row per (project, year, month). has userId, username, projectId, projectName, year, month, totalMinutes. billing rate is NOT in this query - it lives in project_memberships and dragging it into a GROUP BY is more trouble than its worth.

service layer (BillingStatementServiceImpl.generate):

• resolve project scope: caller passes projectIds or we fall back to findActiveProjectsForUser
• fire monthlyBilling() with resolved list
• for each row: single findActiveMembership call (not two - rate and currency both come from the same membership lookup), compute amount = (totalMinutes / 60) * rate, build BillingLineItem

wrap it all in BillingStatement with grandTotal.

notes:

• billing rate/currency on project_memberships, per user per project, set by owner/maintainer
• no rate configured = amount is zero, currency defaults USD

Implementation Sequence:

This is the sequence:

1. Phase I: Create billing statement — computed from time entries × rate; this is not stored
2. Implement invoice lifecycle: Native invoice entity - generate from billing statement, store it, Implement lifecycle: Draft => Sent => Paid lifecycle, Made visible through REST using shareable token
3. Phase 2: Invoice export — render stored invoice as PDF (renderer registry, pluggable formats)
4. Phase 3: QBO Sync

Phase I Complete: Sztab can now compute a monthly billing statement from logged time entries. Each project membership carries a billing rate (hourly, per user). Sztab uses these two to produce a breakdown of hours worked times rate, grouped by month and project. This can be exported as PDF or CSV and used as the basis for preparing an invoice in any external system.

Phase 1 — Billing statement (report, not persisted)

• V25: added billing_rate_per_hour, billing_currency to project_members
• ProjectMember entity + DTO updated with billing fields
• UpdateProjectMemberDto extended with optional billing fields
• ProjectMemberService.updateMember signature extended to carry billing fields
• TimeEntryRepository.monthlyBilling() — new JPQL query, one row per (project, year, month)
• BillingStatement + BillingLineItem DTOs
• BillingStatementService + impl — resolves project scope, joins billing rate from membership, computes hours x rate per line item (single membership lookup per row)
• BillingStatementController — GET /api/projects/{projectId}/billing/statement
• ConsolidatedBillingController — GET /api/billing/statement/consolidated (no project scope, spans all user memberships)

Invoice Lifecycle defined and implemented:

InvoiceStatus enum: DRAFT, SENT, PAID
Invoice entity: status, sent_at, paid_at fields
InvoiceService.markSent: transitions DRAFT => SENT, records sentAt
InvoiceService.markPaid: transitions SENT => PAID, records paidAt
InvoiceController: PATCH /api/invoices/{id}/sent, PATCH /api/invoices/{id}/paid

UI for billing and invoicing:

Frontend additions

1. two type files (billing.ts, invoice.ts)
2. two API modules (billing.ts, invoices.ts),
3. and two pages (InvoiceListPage, InvoiceDetailPage).

Existing files modified:

• App.tsx (routes),
• Sidebar.tsx (nav item),
• ProjectMembersPage.tsx (billing rate field on member edit).

being integration tested

Phase 3 - QBO Sync - https://tigase.dev/sztab/~issues/158