@substrat-run/engine-invoicing

Invoicing engine for Substrat — accumulates invoice bases (Swedish: fakturaunderlag) from billable events and makes them immutable once exported.

It produces the basis for an invoice: per-customer collections of billable lines with frozen prices and provenance, ready to hand to whatever actually issues invoices (typically an accounting connector). It is not a ledger, not accounts receivable, not payment tracking.

What it owns

• Exported means immutable — nothing appends, nothing edits, exporting twice throws.
• One document, one currency — a mixed-currency delivery is rejected at write time.
• Snapshot, not join — prices are frozen from the event payload, with provenance kept.
• Idempotent on replay — the source order is the dedup key, so a redelivery never bills twice.

Install

pnpm add @substrat-run/engine-invoicing

import { invoicingModule } from '@substrat-run/engine-invoicing';

host.registerModule(invoicingModule);

That's the whole integration. Lines arrive by event, never by call: the engine consumes workorder.completed and commerce.order-placed with zero imports from either producer, parsing its own Zod view of each payload. To make a new domain billable, emit an event — you never import this engine to do it.

Documentation

https://substrat.ahlstrand.es/engines/invoicing/ — the domain model and invariants, the operation/permission surface, event contracts and versioning, and how to compose or extend it.

The docs site is the single source of truth; this README deliberately doesn't restate it.

Related packages

• @substrat-run/kernel — the scope-host contract these operations run on
• @substrat-run/engine-workorder — the producer of the billable events this engine consumes

Status

Pre-release (0.x): surfaces change without notice until the first vertical ships.