Integration Architecture

Auteur
Affiliations

[Author Name]

Université de Toulon

LIS UMR CNRS 7020

Date de publication

2026-10-03

Purpose of this Document

This document defines the integration strategies, patterns, and specifications for [System Name], covering both internal component interactions and external system interfaces.

Integration Strategy

Integration Principles:
  - [Key principle 1, e.g., "API-first design"]
  - [Key principle 2, e.g., "Event-driven for asynchronous processes"]
  - [Key principle 3, e.g., "Contract-driven development"]

Integration Types:
  Synchronous:
    - REST APIs: [When to use]
    - GraphQL: [When to use]
    - gRPC: [When to use]
    - SOAP: [When to use, if applicable]
  
  Asynchronous:
    - Message Queues: [When to use]
    - Event Streams: [When to use]
    - Webhooks: [When to use]
    - File Transfer: [When to use, if applicable]

Integration Architecture Overview

graph TD
    A[Client Applications] --> B[API Gateway]
    B --> C[Backend Services]
    C --> D[Databases]
    C --> E[Message Broker]
    E --> F[Event Consumers]
    B --> G[External Systems]
    H[Partner Systems] --> B

System Interfaces

@startuml
package "Integration Layer" {
    interface "Public API" as api
    interface "Event Bus" as events
    interface "Message Queue" as queue
    
    component [API Gateway]
    component [Event Handler]
    component [Queue Manager]
    
    api - [API Gateway]
    events - [Event Handler]
    queue - [Queue Manager]
}

cloud "External Systems" {
    [System A]
    [System B]
}

[API Gateway] --> [System A]
[Event Handler] --> [System B]
@enduml

Interface Contracts

API Contracts:
  Version Control:
    Strategy: [API versioning approach]
    Deprecation: [Policy for deprecating APIs]
    
  Format:
    Primary: [OpenAPI/GraphQL/Proto/RAML/etc.]
    Documentation: [Link to main documentation]
    Change Process: [How contracts are updated]
  
  Standards:
    Authentication: [Methods]
    Rate Limiting: [Approach]
    Error Handling: [Standard error format]
    Pagination: [Standard approach]
    Filtering: [Standard approach]

Event Contracts:
  Version: [Versioning strategy]
  Schema: [Avro/JSON Schema/Protocol Buffers/etc.]
  Validation: [When/how validation occurs]
  Routing: [Topic/routing patterns]
  Delivery: [Guarantees]

Integration Patterns

Pattern Use Case Implementation Example
Request/Response Synchronous operations REST/GraphQL APIs User authentication
Publish/Subscribe Event notifications Message broker Order status updates
Event Sourcing State tracking Event store Audit logging
CQRS Performance optimization Split read/write models Product catalog
Saga Distributed transactions Choreography/Orchestration Order processing
API Gateway Unified access API management platform Client applications
BFF (Backend For Frontend) UI optimization Purpose-built APIs Mobile application
Webhook External notifications HTTP callbacks Payment notifications

Message Formats

REST API Example

{
  "id": "123",
  "timestamp": "2023-06-15T14:22:00Z",
  "type": "order.created",
  "data": {
    "orderId": "ORD-12345",
    "customer": {
      "id": "CUST-789",
      "name": "Example Customer"
    },
    "items": [
      {
        "productId": "PROD-456",
        "quantity": 2,
        "price": 29.99
      }
    ],
    "total": 59.98
  }
}

Event Message Example

Sample Message Format:
  header:
    version: "1.0"
    timestamp: "2023-06-15T14:22:00Z"
    correlation_id: "corr-123456"
    source: "order-service"
    type: "order.created"
  payload:
    orderId: "ORD-12345"
    customerId: "CUST-789"
    items:
      - productId: "PROD-456"
        quantity: 2
        price: 29.99
    total: 59.98

Protocol Specifications

REST APIs

  • Base URL Structure: https://api.example.com/v1/resources
  • Authentication Method: OAuth 2.0 with JWT
  • Rate Limiting: 1000 requests per minute per client
  • Versioning Strategy: URI path versioning (e.g., /v1/resource)
  • Standard Headers:
    • Authorization: Bearer {token}
    • Content-Type: application/json
    • Accept: application/json
    • X-Correlation-ID: {uuid}
  • Status Codes:
    • 200: Success
    • 201: Created
    • 400: Bad Request
    • 401: Unauthorized
    • 403: Forbidden
    • 404: Not Found
    • 429: Too Many Requests
    • 500: Internal Server Error

Message Queues

  • Queue Naming Conventions: {environment}.{domain}.{action}
  • Message Persistence: 7 days
  • Delivery Guarantees: At-least-once
  • Error Handling: Dead letter queue after 3 retries
  • Message Size Limit: 256KB
  • Partitioning Strategy: By entity ID

Events

  • Event Schema Registry: [URL or tool]
  • Naming Convention: {domain}.{entity}.{action}
  • Event Versioning: Schema versioning with backward compatibility
  • Retry Policies: Exponential backoff with jitter
  • Consumer Groups: One consumer group per service
  • Error Handling: Error topic for failed processing

Service Contracts

@startuml
participant "Consumer" as C
participant "Provider" as P
database "Service Registry" as SR

C -> SR: Discover Service
SR --> C: Service Contract
C -> P: Request (per contract)
P --> C: Response
@enduml

System Integration Inventory

External Systems Integration

External Dependencies:
  APIs:
    - System: [External system name]
      Owner: [Company/team]
      Protocol: [REST/GraphQL/gRPC/SOAP/etc.]
      Purpose: [Business function]
      Data: [Key data exchanged]
      SLA: [Response time/availability/etc.]
      Authentication: [Method]
      Failure Impact: [Business impact]
      Fallback: [Alternative process]

  Events:
    - Stream: [Event stream name]
      Source: [Provider]
      Pattern: [pub/sub|queue]
      Volume: [Expected events/second]
      Latency: [Requirements]
      Data: [Key information]

Internal Integration Inventory

Service-to-Service:
  Synchronous:
    - Consumer: [Service name]
      Provider: [Service name]
      Pattern: [Request/Response]
      Protocol: [REST/GraphQL/gRPC]
      Purpose: [Function]
      Criticality: [High/Medium/Low]
  
  Asynchronous:
    - Publisher: [Service name]
      Consumers: [Service names]
      Pattern: [Pub/Sub]
      Protocol: [AMQP/Kafka/etc.]
      Events: [Event types]
      Purpose: [Function]

Interface Patterns

Synchronous:
  Pattern: Request/Response
  Protocol: [REST/GraphQL/gRPC]
  SLA: 
    Availability: 99.9%
    Response Time: <500ms
    Rate Limits: 1000 rps

Asynchronous:
  Pattern: Pub/Sub
  Protocol: [AMQP/Kafka/NATS/etc.]
  Guarantees:
    Delivery: At-least-once
    Ordering: [Per partition/None]
    Durability: [Persistent/Ephemeral]

API Management

API Gateway:
  Implementation: [Product/platform]
  Features:
    - Authentication
    - Authorization
    - Rate Limiting
    - Request Validation
    - Response Transformation
    - Analytics
    - Caching

Developer Portal:
  Documentation:
    - API Reference
    - Tutorials
    - SDKs
  Self-Service:
    - API Key Management
    - Usage Dashboard
    - Sandbox Environment

Integration Security

Authentication:
  External: [OAuth 2.0, API Keys, mTLS, etc.]
  Internal: [Service accounts, mTLS, JWT, etc.]

Authorization:
  Model: [RBAC, ABAC, etc.]
  Enforcement: [API Gateway, Service Mesh, Code]

Data Protection:
  Transport: [TLS 1.3]
  Storage: [Encryption method]
  PII Handling: [Approach]

Integration Governance

Standards Enforcement:
  - Contract Validation
  - Security Review
  - Performance Testing
  - Compatibility Testing

Monitoring:
  - API Usage Metrics
  - Error Rates
  - Response Times
  - SLA Compliance

Template Validation Checklist

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