EventBridge Commerce

Enterprise Microservices Messaging Platform

A stakeholder-ready architecture showcase demonstrating scalable service communication, event streaming, reliable queue-based routing, retry handling, and dead letter processing using Spring Boot Microservices Architecture, Kafka, and RabbitMQ.

Order Service
Kafka Stream
Payment Service
Inventory Service
Shipping Service
RabbitMQ Queue
Notification Service
Retry Queue
Dead Letter Queue

Executive Overview

Asynchronous Order Orchestration for Enterprise Scale

EventBridge Commerce is designed to demonstrate how a core transactional business process—enterprise commerce order-processing—can be modularized into isolated microservices communicating through asynchronous messaging protocols.

By decoupling services, the platform ensures that spikes in order volume do not cascade into downstream systems, payments are validated reliably, stock reservations are managed safely, shipping requests are dispatched sequentially, and operations teams maintain real-time situational visibility over execution pipelines.

⏱️

Workflow Coordination

Faster order lifecycle completion using concurrent, asynchronous execution pathways.

🔗

Reduced Coupling

Eliminate tight HTTP dependencies between services to increase domain independence.

📈

Better Scalability

Scale transaction-heavy services independently based on specific demand.

🛡️

Failure Isolation

Ensure payment timeouts or third-party API issues do not disrupt order intake.

👁️

Operational Visibility

Real-time distributed status tracing across all decoupled endpoints.

♻️

Safer Retry Handling

Isolate temporary errors from permanent processing exceptions via dead-letter routing.

Tech Stack

Core technologies engineered to run this event-driven commerce architecture.

Spring Boot Microservices Architecture

Used to design independent business services for order, payment, inventory, shipping, and notification workflows. Each service owns its business responsibility and communicates through events and messages instead of tight direct dependencies.

Kafka

Used for high-throughput event streaming between microservices. Kafka is used to publish and consume business events such as order-created, payment-approved, inventory-reserved, shipment-created, and notification-requested.

RabbitMQ

Used for reliable queue-based message routing, task distribution, retry handling, notification processing, and dead letter queue workflows.

Architecture Overview

Distributed topology separating real-time event distribution from transaction queue worker models.

Customer Order
Order Service
Kafka Event Stream
Payment Service
Inventory Service
Retry Queue
Shipping Service
RabbitMQ Queue
Dead Letter Queue
Notification Service
Operations Review

1. Event Streaming (Kafka)

Kafka acts as our distributed event log. Business operations (like creating an order) publish immutable facts (events). Downstream services consume these asynchronously to perform heavy database updates.

2. Reliable Task Queues (RabbitMQ)

RabbitMQ controls delivery guarantees for specific jobs. It handles target-to-consumer queue distribution, acknowledgment flags, backoffs, and routing constraints for execution tasks like sending user notifications.

3. Isolated Failure Routines

Temporary exceptions (like API timeouts) trigger retry limits in the Retry Queue before escaping. Persistent issues route to the DLQ, ensuring clean failure boundaries and system stability.

Microservices Responsibilities

A breakdown of independent domain microservices, defining clear logic inputs and outputs.

Order Service Producer
Business Responsibility Handles customer order intake, validates order details, manages order lifecycle status, and publishes order-created events.
Input Source Customer order request
Output Target order-created event (Kafka Topic)
Failure Scenario Invalid order details, duplicate order request, or order validation failure
Payment Service Consumer/Producer
Business Responsibility Consumes order-created events, processes payment validation, determines payment status, and publishes payment-approved or payment-failed events.
Input Source order-created event (Kafka Topic)
Output Target payment-approved event or payment-failed event
Failure Scenario Payment declined, payment timeout, or payment processing failure
Inventory Service Consumer/Producer
Business Responsibility Consumes payment-approved events, reserves inventory, releases inventory when downstream processing fails, and publishes inventory-reserved or inventory-rejected events.
Input Source payment-approved event (Kafka Topic)
Output Target inventory-reserved event or inventory-rejected event
Failure Scenario Item out of stock, reservation timeout, or inventory conflict
Shipping Service Consumer/Producer
Business Responsibility Consumes inventory-reserved events, creates shipment records, updates fulfillment progress, and publishes shipment-created events.
Input Source inventory-reserved event (Kafka Topic)
Output Target shipment-created event (RabbitMQ routing key)
Failure Scenario Shipping provider unavailable, invalid address, or shipment creation failure
Notification Service Consumer
Business Responsibility Consumes notification messages from RabbitMQ and sends customer-facing and operations-facing updates.
Input Source notification message (RabbitMQ queue)
Output Target customer-notified message
Failure Scenario Notification delivery failure, retry exhausted, or message sent to dead letter queue

Messaging Flow

Visualizing differences in messaging protocols across normal execution pipelines and failure recovery paths.

A. Event Streaming Flow

Kafka-Driven
Order Created
Payment Started
Payment Approved
Inventory Reserved
Shipment Created

Events are immutable logs of facts that already occurred in the system. Kafka is optimized for this style of high-throughput publish-subscribe streaming. Multiple independent services listen to the same topic stream concurrently to trigger their respective processing rules without ordering constraints.

B. Queue-Based Message Flow

RabbitMQ-Driven
Notification Requested
RabbitMQ Message Queue
Notification Service
Notification Sent

Messages represent command tasks that must be processed reliably by a target service. RabbitMQ excels here, handling complex routing keys, point-to-point delivery configurations, delivery receipts, consumer load balancing, and immediate execution status callbacks.

C. Failure Handling Flow

Reliability Pipeline
Message Failed
Retry Attempt 1
Retry Attempt 2
Retry Attempt 3
Dead Letter Queue
Operations Review

Temporary failures (e.g. rate limits or network glitches) are retried at staggered intervals. Storing message state in dedicated Retry queues prevents resource lockups. If retries hit the max limit, the payload moves to a Dead Letter Queue (DLQ), preserving the message for inspection by operators.

Live Workflow Simulation

Simulate transactional operations, queue propagation, and failure workflows in real time with broker partition and speed controls.

1
Ingest
2
Events (Kafka)
3
Routing (Rabbit)
4
Dispatch
Speed
Healthy
Order Service
Kafka Topic
Payment Service
Inventory Svc
Shipping Svc
RabbitMQ Queue
Notification Svc
Retry Queue
DLQ (Dead Letter)

Kafka Broker Partition commits

Part-0
Part-1
Part-2

RabbitMQ Queue Buffer

Queue Empty

Broker metrics

Kafka Commit Status Idle
RabbitMQ Queue Size 0 msgs
Retry Attempts 0 / 3
DLQ Mailbox 0 msgs

Simulation Console Logs

[17:47:45]System initialized. Ready for simulation.

Stakeholder Value

Translating messaging design patterns into business value for enterprise operations.

Accelerated Order Coordination

By processing steps concurrently and routing tasks asynchronously, the platform completes core transactions faster. Client systems receive instant receipts instead of blocking while payment clearances or shipping tasks compile.

  • Decoupled API threads release frontend requests immediately.
  • Shorter checkout cycles improve shopping cart conversion metrics.

Granular Resilience & Reliability

Temporary connection dropouts or system spikes are managed gracefully. Backoffs and isolated retry queues isolate faults, ensuring transient errors do not drop customer requests.

  • Failing services do not drag down upstream order collection.
  • Dead Letter redirection ensures no message is lost.

Scalable Independent Boundaries

As transaction volumes surge (e.g. holiday sales), single components like Payment or Shipping validation can be scaled independently without needing to deploy heavy monolithic replicas.

  • Domain boundaries reduce dependencies between service teams.
  • Simplifies legacy integration updates and isolated database refactoring.

Improved Operational Visibility

Auditing transactional milestones is simplified by tailing published events, providing operations teams with instant diagnostics across distributed environments.

  • Clear separation of transactional tasks (RabbitMQ) and state events (Kafka).
  • Simplified audits of distributed histories and message payloads.

Architecture Decisions

Major architectural engineering decisions and technical rationales.

  • Decision 1: Independent service ownership
    Each service owns one business capability so changes in payment, inventory, shipping, or notification logic do not require changing the entire system.
  • Decision 2: Event-driven communication
    Services communicate through events so they do not need to wait for direct synchronous responses from every downstream system.
  • Decision 3: Kafka for event streaming
    Kafka is used when business events need to be published and consumed across multiple services.
  • Decision 4: RabbitMQ for reliable task routing
    RabbitMQ is used when a specific task needs to be routed, retried, and tracked reliably.
  • Decision 5: Failure handling through retries and dead letter queues
    Temporary failures are retried, and permanently failed messages are moved to a dead letter queue for review.

End-to-End Order Workflow

Tracking transactional orchestration across the system architecture step by step.

01

Customer Submits Order

The client application transmits order specifics via HTTP POST to the API Gateway routing mechanism.

02

Order Validation & Publish

Order Service validates the schema, initializes the record as PENDING, and publishes an order-created event payload onto Kafka.

03

Payment Processing

Payment Service detects the order-created event and validates payment authorization via a mock external merchant gateway.

04

Payment Event Broadcast

Upon success, Payment Service publishes a payment-approved event to Kafka, indicating transactional viability.

05

Stock Reservation

Inventory Service consumes the payment-approved event and reserves items in stock to prevent oversells.

06

Inventory Event Broadcast

Once reserved, Inventory Service publishes an inventory-reserved event to Kafka, prompting fulfillment steps.

07

Fulfillment Manifest Creation

Shipping Service consumes the inventory-reserved event, compiles courier manifests, and prepares shipment records.

08

Shipment Event Broadcast

Shipping Service publishes a shipment-created event to the messaging bus, concluding inventory-dependent processes.

09

RabbitMQ Task Routing

A message task detailing the notification is routed to RabbitMQ to guarantee reliable delivery to the end user.

10

Customer Update Transmission

Notification Service consumes the task from RabbitMQ and sends email/SMS alerts confirming dispatch.

11

Exception Handling Retry Routine

If Notification Service encounters a network error, the message enters a Retry Queue to isolate temporary hiccups.

12

DLQ Redirection

If three retries fail, the message moves to the Dead Letter Queue for operational review, avoiding system-wide blockages.

Technical Interview Talking Points

Essential points to guide technical design reviews and architectural QA sessions.

  • I separated the system into independent microservices based on business capabilities.
  • I used event-driven communication to reduce tight coupling between services.
  • I used Kafka for high-throughput business event streaming.
  • I used RabbitMQ for reliable task routing and retry-based processing.
  • I designed retry and dead letter queue flows for production-style failure handling.
  • I focused on clear architecture communication so both technical and non-technical stakeholders can understand the project.
  • I designed the workflow around real enterprise order-processing patterns.
  • I can explain why Kafka and RabbitMQ serve different messaging needs in the same architecture.

Resume Alignment & Bullet Points

Translating project experience directly into industry-standard Senior backend roles.

Resume Alignment

This project aligns with a Senior Software Engineer profile by demonstrating:

  • Enterprise microservices architecture
  • Event-driven backend design
  • Distributed messaging workflows
  • Service boundary design
  • Messaging reliability
  • Retry and dead letter queue handling
  • Stakeholder communication
  • System design presentation skills
  • Production-style architecture thinking

Resume Bullet Points

Tailored resume highlights showcasing high-impact achievements:

  • Designed an enterprise event-driven microservices messaging platform using Spring Boot Microservices Architecture, Kafka, and RabbitMQ to demonstrate scalable order-processing workflows.
  • Modeled asynchronous communication across order, payment, inventory, shipping, and notification services to improve service independence and workflow reliability.
  • Created a stakeholder-facing live architecture demo explaining event streaming, queue-based routing, retry handling, and dead letter queue processing.
  • Demonstrated production-style failure handling patterns including retry queues, dead letter queues, and operations review workflows.
  • Presented clear service ownership boundaries and messaging flow decisions for distributed enterprise systems.