Backends

@nestarc/jobs ships two backends behind the same JobsService interface.

Backend matrix

Capability	In-memory	BullMQ
Automatic worker startup in JobsModule	✓	✓
Tenant fairness	✓	—
Per-tenant weight control	✓	—
ALS/context propagation	✓	✓
@JobHandler() discovery	✓	✓
Outbox bridge	✓	✓
FakeJobsService support	✓	N/A
Persistent across restarts	—	✓ (Redis)
Multi-process consumption	—	✓
Delayed jobs	— (not modeled)	✓
Retries with backoff	— (not modeled)	✓

In-memory backend

Use forInMemory() when:

• you run a single Nest process
• tenant fairness matters
• you want the simplest local or test setup

Important behavior:

• Workers start automatically when the Nest module initializes.
• Tenant fairness is enforced by the in-process Scheduler.
• This backend is not distributed across multiple processes — each replica has its own queue.

JobsModule.forInMemory({
  jobTypes: ['sendReport'],
  fairness: { defaultWeight: 1, minSharePct: 0.1 },
  concurrency: { tenantCap: 10 },
});

BullMQ backend

Use forBullMQ() when:

• you need Redis-backed persistence and BullMQ workers
• FIFO delivery is acceptable for now

Important behavior:

• Jobs are processed by BullMQ's standard Worker.
• Tenant fairness is not implemented in 0.1.0.
• Fairness-only APIs throw on this backend:
  • setTenantWeight()
  • scheduler()
• Pull-based backend methods are unsupported:
  • peekWaiting()
  • moveToActive()

const backend = new BullMQBackend({
  namespace: 'acme',
  connection: { url: process.env.REDIS_URL! },
  workerConcurrency: 10,
});

JobsModule.forBullMQ({ backend, jobTypes: ['sendReport'] });

Migration plan

Many teams start with forInMemory for early development, then switch to forBullMQ when they need persistence and multi-process consumption. The handler interface (@JobHandler, payload + ctx signatures) is stable across backends, so the switch is a module-registration change plus a Redis deployment — not a handler rewrite.

Note that switching to BullMQ drops tenant fairness in 0.1.0. Plan around that if you rely on weighted scheduling today — you can mitigate it with dedicated queues per tenant tier while a fair BullMQ strategy lands in a later release.