---
type: concept
title: Layer 3 — Core Application Services
aliases:
  - core services
  - application services
  - engine room
  - layer 3
modified: 2026-07-08
tags:
  - architecture
  - architecture-layer
  - workflow
  - approval-queue
  - suitecentral
---

# Layer 3 — Core Application Services

> Integration orchestration, configuration, WorkflowCentral execution, ownership resolution, approval queues, audit logging, and module metrics.

The engine room of the [[pages/concepts/suitecentral-code-architecture|seven-layer code architecture]]: this layer converts operator intent (from [[pages/architecture/http-api-edge|Layer 2]]) into governed, auditable actions against ERP connectors ([[pages/architecture/connector-integration-layer|Layer 6]]). The human-in-the-loop approval queue lives here — high-risk AI-proposed changes are enqueued for operator approval at this layer, never executed inline. Connector writes are gated here through ownership resolution before any connector executes them.

## Questions this layer answers

- What services form the core runtime?
- How are approval queues and audits connected?

Ask them live on the **[Code Architecture Dashboard](https://demo.kstratmdconsulting.com/code-architecture-dashboard.html)** — click the third layer of the infographic.

## Documentation & evidence

- [Source-of-truth model](https://demo.kstratmdconsulting.com/docs/architecture/source-of-truth-model.md) — how ownership resolution decides which system wins
- Proof card: [WorkflowCentral operator](https://demo.kstratmdconsulting.com/docs/review/proof-cards/workflow-central-operator.md)
- Proof card: [Flow templates](https://demo.kstratmdconsulting.com/docs/review/proof-cards/flow-templates.md)
- Proof card: [Audit service](https://demo.kstratmdconsulting.com/docs/review/proof-cards/audit-service.md)

## Related layers

- [[pages/architecture/http-api-edge|Layer 2 — HTTP-API Edge]] — the validated requests this layer acts on
- [[pages/architecture/governance-safety|Layer 5 — Governance & Safety]] — invoked inline at this layer's decision points
- [[pages/architecture/ai-intelligence|Layer 4 — AI & Intelligence]] — whose validated outputs this layer executes
- [[pages/architecture/connector-integration-layer|Layer 6 — Connector & Integration Layer]] — the executors this layer dispatches to

---

*Last refreshed: 2026-07-06*