Backend Services

The backend is a microservices monorepo in the blitz repo, built on Bun + Elysia.

Tech Stack

Layer	Technology
Runtime	Bun (not Node.js)
Framework	Elysia (not Express/Fastify)
ORM	Prisma with PostgreSQL
Language	TypeScript
Testing	Bun built-in test runner
Dependency Injection	InversifyJS

Repository Structure

blitz/src/
├── apps/          # Deployable microservices
├── packages/      # Domain business logic (dual-package pattern)
├── libs/          # Shared libraries (@blitz/lib-*)
└── playground/    # Experimental projects

Dual-Package Pattern

Each domain is split into two packages:

• *a — API layer: controllers, services, schemas, event handlers
• *d — Data layer: Prisma schema, migrations, generated client
• *wf (some domains) — Temporal workflow definitions

Example: casha + cashd = complete cash domain.

Never import generated Prisma clients directly — use factory functions:

// Correct
import { createDefaultCashClient } from "@blitz/cashd";
// Wrong
import { PrismaClient } from "@blitz/cashd/generated";

Domain Packages

Domains nest under packages/finance/, packages/mgmt/, or packages/system/, each as <domain>/<domain-a|d|wf> (not a flat packages/<name>a/<name>d layout):

Domain	Packages	Description
Cash	casha, cashd	Cash management
Close Hub	closehuba, closehubd, closehubwf	Period close management (eclose is the DB schema name, not a package)
Invoice	invoicea, invoiced	Invoicing
Journal	journala, journald	Journal entries
Reconciliation	reconciliationa, reconciliationd	Reconciliation
Core System	coresystema, coresystemd	Core financial operations
Finance Base	finbasea, finbased	Shared finance domain
Finance Agents	financeagents	AI agents scoped to finance domains
Mgmt	mgmta, mgmtd	Multi-tenancy management
System	systema, systemd, systemwf, systemwfp	Users, auth, settings, workflows, proxied activities (SAP, etc.)
System Agents	systemagents	AI agents scoped to system domain

Deployed Microservices (12)

Count matches backendServices[] in fin-infra/railway/backend/infrastructure.ts.

Service	Port	Role
blitz-api	10001	API gateway — single entry point for all clients
blitz-ws	10002	WebSocket server for real-time features
blitz-apimgmt	9999	Management/control-plane API for tenant onboarding (private-only)
blitz-agents	10013	AI agent execution
blitz-excelrw	10014	Excel read/write — .NET, not Bun
blitz-emailprocessor	—	Async email processing worker
blitz-wfw	—	Temporal workflow worker (minimum 1 GB RAM — crashes at 512 MB)
blitz-wfwpdf	—	Temporal PDF workflow worker
blitz-recon	10015	Reconciliation service
blitz-remotecontrol	10016	Remote control
blitz-classicml	—	Python ML Temporal worker
blitz-bapiproxy	10017	SAP/BAPI proxy — .NET, also a Temporal worker on taskqueue-system-sap

wfw runs system, closehub, cash, coresystem, and invoice Temporal workers in parallel.

excelrw and bapiproxy are both .NET 10 (ASP.NET Core), not Bun — see Platform Architecture for the two-file (ELF apphost / PE IL .dll) container detail if debugging one of them.

Additional Services (built, not deployed)

blitz/src/apps/ has 22 directories; 12 have a CI build-push workflow and are the services deployed to Railway (above). The remainder (desktop, email, events, fs, jsontransformer, mcp, pdfwriter, queue, rulesengine, scriptrunner, templaterenderer) exist in the monorepo but are not built or deployed. See Gaps & Roadmap.

API Gateway Pattern

The api service (port 10001) aggregates all domain controllers:

const endpoint = new Elysia({ prefix: "/api" })
  .use(tenantInfoResolverPlugin)
  .use(systemControllers)
  .use(authenticator)
  .guard({}, (app) => app.use(cashControllers).use(journalControllers) /* ... */);

Controller → Service → Prisma Flow

// Controller
const endpoint = new Elysia().group("/payments", (app) =>
  app.post("/filter", async ({ logger, cashPrisma, body }) =>
    await PaymentService.filterInstances(logger, cashPrisma, body), {
      body: queryFilterSchema
    })
);

// Service — static methods, Prisma passed as parameter
export class PaymentService {
  public static async filterInstances(logger, prisma, filter) {
    const { orderBy, where } = QueryBuilder.createQuery(logger, filter, ...);
    return await prisma.payment.findMany({ ...orderBy, ...where });
  }
}

Database

PostgreSQL with multi-schema design. Two databases:

• finance DB: cash, closehub/eclose, journal, invoice, finbase, reconciliation, sys
• mgmt DB: tm (tenant management)

Each *d package has its own Prisma schema targeting specific schemas:

generator client {
  provider   = "prisma-client"
  output     = "../generated"
  runtime    = "bun"        // required
  engineType = "client"
}
datasource db {
  provider = "postgresql"
  schemas  = ["cash", "finbase", "sys"]
}

Multi-Tenancy

Via @blitz/lib-tenancy — header-based (x-blitz-tenant-id) or domain-based. Toggle: TENANCY_ENABLED=true|false.

Available Elysia Context Services

Controllers receive these from DI:

• logger
• rootContainer
• bucketManagementService (RustFS)
• queueService (RabbitMQ — local dev only; RabbitMQ was removed from Railway 2026-07-10 and no deployed service depends on it)
• eventEmitterService
• {domain}Prisma (e.g. cashPrisma, journalPrisma)

Workflows (Temporal)

The wfw service runs Temporal workers. Workflow definitions live in *wf packages. Temporal UI is available on the Railway internal network.