Enterprise HRIS

Problem

Large Indonesian enterprises with 500+ employees need:

• A single HR platform covering the entire employee lifecycle
• Real-time notifications across web and mobile (not polling)
• Distributed processing for heavy workloads (bulk payroll, mass notifications)
• Multi-database strategy for structured HR data and semi-structured logs/chat
• GDPR-compliant data handling with proper access control

Solution

An enterprise HRIS platform with message-driven architecture:

1. Backend Admin (80+ modules) — Payroll, KPI, Performance Appraisal, Layoff, Recruitment, Severance, Notice Letters, Attendance, Leave
2. Backend API (50+ modules) — RESTful API layer for mobile apps and third-party integrations
3. Message Bus — RabbitMQ for async task processing (bulk payroll calculation, mass email/SMS)
4. Real-time Layer — MQTT pub-sub for live notifications, chat, and presence
5. Dual Database — PostgreSQL for relational HR data, MongoDB for chat messages, logs, and documents

Architecture

                  ┌────────────────────┐
                  │   Mobile App       │
                  └────────┬───────────┘
                           │ MQTT (live) / REST API
                  ┌────────▼───────────┐
                  │   Backend API      │
                  │   50+ modules      │
                  └────────┬───────────┘
                           │
          ┌────────────────┼────────────────┐
          │                │                │
   ┌──────▼──────┐  ┌──────▼──────┐  ┌──────▼──────┐
   │ RabbitMQ    │  │ PostgreSQL  │  │  MongoDB     │
   │ (async)     │  │ (HR data)   │  │ (chat/logs)  │
   └──────┬──────┘  └─────────────┘  └─────────────┘
          │
   ┌──────▼──────────────────────────┐
   │  Backend Admin (80+ modules)    │
   │  Payroll · KPI · Appraisal · …  │
   └─────────────────────────────────┘

Key Tech Decisions

RabbitMQ over Redis queues

Redis queues are simpler but lack durability guarantees. RabbitMQ with persistent queues ensures payroll calculations survive server restarts. Exchange-based routing enables targeted delivery — e.g., payroll.processing exchange routes differently than notification.bulk.

MQTT for real-time chat

MQTT (via php-mqtt client) was chosen over WebSocket because mobile apps already use MQTT for push notifications. Reusing the same protocol for chat avoids maintaining two real-time infrastructure stacks. The broker handles topic-based pub-sub: chat/{user_id}, notification/{user_id}.

MongoDB for polymorphic documents

Employee documents (contracts, certificates, ID scans) are semi-structured — each document type has different metadata fields. MongoDB’s flexible schema accommodates this without the overhead of EAV (Entity-Attribute-Value) patterns in PostgreSQL.

GIS with phpgeo

Attendance tracking uses phpgeo for geofence calculations — determining if an employee’s GPS coordinates fall within the office polygon. The library provides Haversine distance, bounding box queries, and polygon containment checks.

Metrics

Metric	Value
Total Modules	130+ (80 Admin + 50 API)
Message Broker	RabbitMQ
Real-time Protocol	MQTT
Databases	PostgreSQL + MongoDB
Export Engines	PhpSpreadsheet + PhpWord + DomPDF