Boken: Distributed Trip Intelligence

Overview

Boken is a geospatial recommendation backend that aggregates travel intelligence from multiple data sources, featuring distributed caching and intelligent API rate limiting.

The system demonstrates backend engineering patterns for building responsive, cost-effective recommendation systems.

Architecture

Caching Strategy

• Redis layer: Reduces redundant API calls by 70%
• TTL-based invalidation: Fresh data for time-sensitive queries
• Cache warming: Proactive population for popular destinations

API Orchestration

• Rate limiting: Respects third-party API quotas
• Circuit breaker: Graceful degradation on upstream failures
• Request deduplication: Coalesces concurrent identical queries

Geospatial Engine

• MongoDB geospatial indexes: Sub-50ms proximity queries
• Polygon-based region matching: Complex boundary definitions
• Distance calculations: Haversine formula for accurate measurements

Technical Stack

• Runtime: Node.js with Express
• Database: MongoDB (geospatial) + Redis (caching)
• APIs: OpenStreetMap, weather services, POI databases

Data Flow

User Query
    ↓
Cache Check (Redis)
    ↓ (miss)
Rate Limiter
    ↓
API Aggregator
    ↓
MongoDB Enrichment
    ↓
Cache Population
    ↓
Response

Performance Metrics

• Average response time: <200ms (cache hit)
• Cache hit rate: ~70% for popular queries
• API cost reduction: Significant savings via intelligent caching

Repository

Available on GitHub with API documentation and deployment instructions.