In today’s modern workplaces, a single employee app often handles a lot more than just attendance.
From clocking in, booking a gym slot, applying for leave, to getting birthday wishes 🎂 and claiming reimbursements —
everything runs through microservices.
Let’s dive deep into the architecture, microservices, and how communication happens inside an employee app! 🏢🚀
🛠️ Core Features We Need to Build
- Attendance Tracking (Clock In/Out)
- Leave Application
- Sports Slot/Gym Booking
- Employee Directory
- Birthday Wishes & Notifications
- Team Management View
- Salary Slip & Reimbursement Claims
- Medical Insurance Claims
🧩 Microservices Breakdown
| Microservice | Responsibility |
|---|---|
| Attendance Service | Clock in/out tracking |
| Leave Management Service | Apply, approve, track leaves |
| Sports & Gym Booking Service | Book time slots |
| Employee Directory Service | Maintain employee details |
| Birthday Notification Service | Manage birthday notifications |
| Team Management Service | Control who sees what |
| Payroll Service | Salary slips, bonuses |
| Reimbursement Service | Travel, food, other reimbursements |
| Medical Claim Service | Insurance claims management |
| Email Notification Service | Send birthday wishes, reminders |
📲 Step-by-Step Flow (With Sync/Async Communication)
🕒 Step 1: Employee Clocks In/Out (Attendance)
🔥 Services Involved:
- Attendance Service
📞 Communication:
- User App → Attendance Service: (Sync, REST API)
✅ Why synchronous?
- Immediate feedback needed: "Clocked In at 9:01 AM".
🌴 Step 2: Employee Applies for Leave
🔥 Services Involved:
- Leave Management Service
- Manager Notification Service (optional)
📞 Communication:
- User App → Leave Management Service: (Sync, REST API)
-
Leave Management Service → Manager Notification Service: (Async, Kafka Event
LEAVE_APPLIED)
✅ Why mixed?
- Leave application must show success immediately.
- Manager approval notifications can be async.
🏋️ Step 3: Book a Gym or Sports Slot
🔥 Services Involved:
- Sports & Gym Booking Service
📞 Communication:
- User App → Sports & Gym Service: (Sync, REST API)
✅ Why synchronous?
- User needs real-time slot availability and booking confirmation.
🧑💼 Step 4: View Employee Directory or Team Members
🔥 Services Involved:
- Employee Directory Service
- Team Management Service
📞 Communication:
- User App → Team Management Service → Employee Directory Service: (Sync, REST API)
Access Control is checked first (team only), then data is fetched.
✅ Why synchronous?
- Immediate access control check and data fetch needed for smooth UX.
🎂 Step 5: Birthday Notifications and Wishes
🔥 Services Involved:
- Birthday Notification Service
- Email Notification Service
- Team Management Service
📩 Communication:
-
Birthday Notification Service → Email Notification Service: (Async, Kafka event
SEND_BIRTHDAY_WISH) - Birthday Notification Service → Team Management Service: (Sync, REST) to fetch list of colleagues.
✅ Why mixed?
- Wish emails can be scheduled (async).
- Fetching colleague list needs fast response (sync).
📄 Step 6: Download Salary Slips
🔥 Services Involved:
- Payroll Service
📞 Communication:
- User App → Payroll Service: (Sync, REST API)
✅ Why synchronous?
- Employee expects instant salary slip download.
🧾 Step 7: Submit Reimbursement or Medical Claims
🔥 Services Involved:
- Reimbursement Service
- Medical Claim Service
📞 Communication:
- User App → Reimbursement Service: (Sync, REST API)
User App → Medical Claim Service: (Sync, REST API)
Claim Services → Payroll Service: (Async, Kafka Event
CLAIM_APPROVED) for payout.
✅ Why mixed?
- Claim submission needs instant confirmation.
- Processing/payout happens later asynchronously.
🗺️ Full Microservices Communication Map
| Action | Microservice(s) | Communication Type |
|---|---|---|
| Clock In/Out | Attendance Service | Sync |
| Apply Leave | Leave Service → Manager Notification | Sync → Async |
| Book Gym Slot | Sports & Gym Service | Sync |
| View Team Members | Team Management → Employee Directory | Sync |
| Birthday Wish Email | Birthday Service → Email Notification | Async |
| Download Salary Slip | Payroll Service | Sync |
| Submit Reimbursement | Reimbursement Service | Sync → Async |
| Medical Insurance Claim | Medical Claim Service | Sync → Async |
🎯 Why Sync vs Async in Corporate Employee App?
| Synchronous (REST API) | Asynchronous (Kafka/Event Bus) |
|---|---|
| User actions needing instant feedback (clock-in, booking slot, applying leave) | System notifications, emails, claim payouts |
| Reading data (team members, salary slip) | Sending birthday wishes, notifying approvals |
📚 Real-World Observations
- Apps like DarwinBox, SAP SuccessFactors, Workday, Keka HRMS use this approach.
- Kafka is heavily used internally for events (leave approval, birthday wishes).
- REST APIs or GraphQL are used externally for client → server communication.
✍️ Final Thought
Designing a full-fledged Employee Management App is not just CRUD operations.
It’s about balancing fast user interactions with scalable system processing, by choosing synchronous or asynchronous communication wisely.
This architecture ensures that:
- Employee experience stays smooth.
- Internal systems are resilient, scalable, and efficient. 🚀