Payroll & HR Migration · Strangler-Fig + Replay Architecture

Migrating legacy payroll & HR to a
Replay-native, compliance-ready V2 platform

A seven-stage scroll journey through the Replay Platform — from disconnected silos to a live, observable, replay-native V2 operating model.

01 · Platform Vision 02 · Cross-Product Replay 03 · Replay Workflow 04 · Integration Architecture 05 · Replay Engine Detail 06 · Target End State 07 · Azure Tech Stack
Scroll to explore the architecture

© Jinan Kordab

STEP 1 / 7
Step 1: Fragmented Landscape Step 2: Replay Platform Step 3: Platform Integration Architecture Step 4: Operational Workflow Step 5: Dual-Purpose Engine Step 6: Shared Operational History Step 7: Unified End State Tech Stack
01
OF 07
STEP 01 // STRATEGIC RATIONALE
Why REPLAY: From Siloed Products to a Shared Compliance Backbone
A Legacy Product (poor traceability, limited docs) and a Connected Product Estate (Payroll, People/HR, Time/Attendance) both feed the REPLAY Platform. The output is a Shared Operational Backbone — event history, audit trail, error tracking, replay state — delivering end-to-end Observability & Compliance evidence.
STEP 02 // REPLAY OVERVIEW
REPLAY: Unified Access, Product Boundaries & Shared Operational History
V1 legacy and acquired products (Payroll, People, Time) feed the REPLAY control plane through two paths: Unified Access (single operator entry point) and clearly-scoped Product Boundaries. Replay Control restarts from any failure point while preserving the original run — producing Shared Operational History with audit trail, error visibility, and cross-product tracing.
STEP 03 // OPERATIONAL WORKFLOW
Replay Workflow: Select → Correct → Reuse → Re-execute → Audit
Operators (1) Select the failed step via unified access, (2) Apply a rule fix, mapping fix, or manual override, (3) Reuse valid prior steps as a trusted baseline, (4) Re-execute only affected downstream work, and (5) Record an immutable audit linking the replay back to its source run — guaranteeing controlled correction with full audit continuity.
STEP 04 // INTEGRATION ARCHITECTURE
REPLAY Integration: Canonical Mapper + Unified Auth Gateway → V2
Raw data from V1 (Legacy DB & Schema) and acquired products (Payroll, People, Time — siloed DBs) flows into the Canonical Mapping Layer, normalizing schemas and resolving field mismatches. Unified Identity & Access (single auth gateway) authenticates all operators into the Unified Operator Portal, which triggers the Replay Engine — both paths writing to the Centralized Datastore, the single source of truth.
STEP 05 // REPLAY ENGINE INTERNALS
Dual-Use REPLAY Engine: Day-to-Day Fixes & Bulk Tenant Migration
IAM authenticates two operator paths — Operator Portal (day-to-day single fixes) and Migration Controller (tenant-by-tenant bulk transfers) — both fed by CDC continuous sync. The REPLAY ENGINE runs four sequential stages: (A) Immutable Ledger Snapshot for compliance evidence, (B) Scope & preserve trusted history, (C) Inject authorized correction, (D) Safe financial execution with idempotency preventing double payments.
STEP 06 // TARGET END STATE
Strangler-Fig Complete: Replay Engine Becomes a Permanent V2 Feature
Strangler Fig complete. The Fragmented Landscape (V1 & acquired apps) is DECOMMISSIONED. The Migration Controller is spun down. The Canonical Mapping Layer is retired or repurposed. IAM authenticates all staff directly into the Native V2 Operator Portal, which triggers the now-permanent Replay Engine for daily operational resilience — reading and writing live data via the Centralized Datastore.
STEP 07 // AZURE IMPLEMENTATION STACK
Engineering Stack: Azure-Native End-to-End Implementation
Legacy SQL Server/Oracle → SQL Server CDC/Debezium → Canonical Mapper (C# Worker Service) + Entra ID/Azure AD + Operator Portal (React + TypeScript + MSAL) + Migration Controller (Azure Durable Functions/C#) → Replay Orchestrator (.NET 8/C#) → Azure Service Bus → Azure Container Apps (C#) → Azure Cache for Redis (idempotency) → Azure SQL Database → .NET Microservices/APIs V2 Platform.

Architecture journey complete

The REPLAY Platform delivers a compliant, fully auditable migration path for payroll, people, and time accounting systems — using CDC ingestion, canonical schema mapping, and a permanent Replay Engine that guarantees compliance, safe corrections, and cross-product audit continuity into the V2 platform.

Safer Recovery

Controlled replay corrections prevent downstream damage. Every fix is bounded, selective, and linked to a locked audit snapshot.

Full Observability

End-to-end event history, cross-product tracing, and root cause analysis built natively into the platform — not bolted on.

Compliance by Design

Immutable ledger snapshots and idempotency guards satisfy audit requirements automatically, without manual reconciliation.