Integration Architecture

Purpose

Design robust integration patterns for external services, APIs, and third-party systems with proper error handling, resilience, and data synchronization.

When to Use

• External API integration
• Third-party service connections
• B2B data exchange
• Service mesh design

Prerequisites

• External services identified
• API documentation available
• SLAs and rate limits known
• Data mapping requirements

Process

Step 1: Catalog External Services

For each service:
- Service name and purpose
- API type (REST, SOAP, etc.)
- Authentication method
- Rate limits
- SLA/availability
- Data format

Step 2: Design Integration Patterns

Pattern options:
- Direct sync: Real-time API calls
- Async queue: Message-based
- Webhook: Event-driven
- Batch: Scheduled sync
- Cache-first: Read from cache

Step 3: Plan Resilience

Resilience patterns:
- Circuit breaker
- Retry with backoff
- Timeout configuration
- Fallback responses
- Bulkhead isolation

Step 4: Design Data Mapping

For each integration:
- External → internal mapping
- Data transformation rules
- Validation requirements
- Error handling
- Conflict resolution

Step 5: Document Integration Contracts

Contract includes:
- Endpoint details
- Request/response schemas
- Error codes
- Rate limits
- SLA expectations

Inputs

Input	Type	Required	Description
external_apis	JSON	Yes	Service catalog
requirements	Markdown	Yes	Integration needs

Outputs

Output	Type	Description
integration_architecture.md	Markdown	Integration design
service_contracts	YAML	API contracts
data_mapping.md	Markdown	Field mappings

StudyAbroad-Specific Considerations

• University databases: Batch sync recommended
• Visa services: Async queue-based
• Housing APIs: Cache-first pattern
• Rate limits vary by provider

Integration Points

• Developer Agent: Implementation
• Test Manager: Integration test design
• Operations Agent: Health monitoring

Examples

Integration Architecture - StudyAbroad-v1

EXTERNAL SERVICES:

1. University Database API
   Type: REST API
   Auth: API Key
   Rate limit: 100 req/min
   SLA: 99.0%
   Pattern: Batch sync (nightly) + cache
   
2. Visa Service API
   Type: REST API
   Auth: OAuth2
   Rate limit: 50 req/min
   SLA: 99.5%
   Pattern: Async (queue-based)
   
3. Housing Provider API
   Type: GraphQL
   Auth: API Key
   Rate limit: 200 req/min
   SLA: 99.0%
   Pattern: Cache-first (1hr TTL)

INTEGRATION PATTERNS:

University Sync:
┌──────────┐     ┌──────────┐     ┌──────────┐
│ Scheduler│────>│ Sync Job │────>│University│
│ (nightly)│     │ Worker   │     │   API    │
└──────────┘     └────┬─────┘     └──────────┘
                      │
                      ▼
                ┌──────────┐
                │ Database │
                │ (upsert) │
                └──────────┘

Visa Status Check (Async):
┌──────────┐     ┌──────────┐     ┌──────────┐
│ User     │────>│   SQS    │────>│  Worker  │
│ Request  │     │  Queue   │     │          │
└──────────┘     └──────────┘     └────┬─────┘
                                       │
                      ┌────────────────┘
                      ▼
                ┌──────────┐     ┌──────────┐
                │  Visa    │────>│ Webhook/ │
                │  API     │     │ Callback │
                └──────────┘     └──────────┘

RESILIENCE:

Circuit Breaker Config:
- Failure threshold: 5 failures
- Recovery timeout: 30 seconds
- Half-open max calls: 3

Retry Policy:
- Max retries: 3
- Initial delay: 1 second
- Backoff multiplier: 2
- Max delay: 10 seconds

Fallback Strategies:
- University API down: Serve cached data
- Visa API down: Queue request, notify user
- Housing API down: Show "temporarily unavailable"

Validation

• All external services cataloged
• Integration patterns defined
• Resilience mechanisms designed
• Data mappings documented
• SLAs understood and planned for