Performance Optimization

Learn how to optimize your feature flag implementation for maximum performance and minimal latency.

Overview

DarkFeature is built for high-performance applications. Our edge-first architecture ensures that feature flag evaluations happen as close to your users as possible, with sub-millisecond response times globally.

Performance Features

Edge Computing

Global Edge Network: Feature flags are cached at 200+ edge locations worldwide
Sub-10ms Latency: Average response time under 10ms globally
99.99% Uptime: Enterprise-grade reliability with automatic failover

SDK Performance

Client-Side SDKs

Lazy Loading: Only fetch flags when needed
Local Caching: Intelligent caching with automatic updates
Streaming Updates: Real-time flag changes via WebSocket connections
Bundle Size: Minimal impact on your application bundle (< 15KB gzipped)

Server-Side SDKs

Connection Pooling: Efficient HTTP connection reuse
Bulk Operations: Evaluate multiple flags in a single request
Background Updates: Non-blocking flag synchronization
Memory Optimization: Efficient in-memory flag storage

Caching Strategy

Multi-Layer Caching

Browser Cache: Client-side caching for instant evaluations
CDN Cache: Global CDN for reduced latency
Application Cache: Server-side caching for high-throughput scenarios
Database Cache: Optimized data layer for complex targeting

Cache Invalidation

Smart Invalidation: Only invalidate affected flags
Gradual Rollout: Prevent cache stampedes during updates
TTL Management: Configurable time-to-live settings

Performance Best Practices

Implementation Guidelines

1. Use Appropriate SDK Methods


// ✅ Good: Use async for better performance
const isEnabled = await client.isEnabled('feature-flag')
 
// ❌ Avoid: Synchronous calls can block execution
const isEnabled = client.isEnabledSync('feature-flag')

2. Batch Flag Evaluations


// ✅ Good: Evaluate multiple flags at once
const flags = await client.getAllFlags()
 
// ❌ Avoid: Multiple individual calls
const flag1 = await client.isEnabled('flag-1')
const flag2 = await client.isEnabled('flag-2')

3. Implement Local Fallbacks


// ✅ Good: Provide fallback values
const isEnabled = await client.isEnabled('feature-flag', false)
 
// ✅ Good: Handle network failures gracefully
try {
  const isEnabled = await client.isEnabled('feature-flag')
} catch (error) {
  // Use local fallback or default behavior
  const isEnabled = false
}

Targeting Optimization

1. Efficient Targeting Rules

Simple Rules First: Order targeting rules by complexity
User Segments: Pre-compute user segments when possible
Avoid Complex Expressions: Keep targeting logic simple

2. User Context Optimization


// ✅ Good: Provide stable user context
const context = {
  userId: user.id,
  tier: user.subscription.tier,
  region: user.location.region,
}
 
// ❌ Avoid: Frequently changing context
const context = {
  userId: user.id,
  timestamp: Date.now(), // This changes every evaluation!
  randomValue: Math.random(),
}

Monitoring Performance

Key Metrics to Track

Response Time Metrics

Flag Evaluation Time: Time to evaluate a single flag
Bulk Evaluation Time: Time to evaluate multiple flags
Network Latency: Time for SDK to communicate with DarkFeature
Cache Hit Rate: Percentage of evaluations served from cache

Application Impact

Bundle Size Impact: Additional JavaScript bundle size
Memory Usage: RAM consumption by the SDK
CPU Usage: Computational overhead of flag evaluations
Network Requests: Number of requests to DarkFeature APIs

Performance Dashboard

Access real-time performance metrics in your DarkFeature dashboard:

Response Times: P50, P95, P99 latencies globally
Cache Performance: Hit rates and invalidation patterns
SDK Performance: Client and server-side performance metrics
Error Rates: Failed evaluations and fallback usage

Troubleshooting Performance Issues

Common Performance Problems

1. High Latency

Symptoms: Slow flag evaluations, user experience impact Solutions:

Enable local caching in SDK configuration
Use bulk evaluation methods
Implement proper fallback strategies
Check network connectivity

2. Memory Leaks

Symptoms: Increasing memory usage over time Solutions:

Properly dispose of SDK instances
Avoid creating multiple SDK instances
Use SDK connection pooling

3. Bundle Size Issues

Symptoms: Large JavaScript bundle size Solutions:

Use tree-shaking compatible imports
Consider server-side evaluation for heavy applications
Use dynamic imports for feature-specific code

Performance Testing

Load Testing


// Example load test for flag evaluations
const clients = Array.from({ length: 100 }, () => new DarkFeatureClient())
 
const startTime = Date.now()
const promises = clients.map(client => client.isEnabled('high-traffic-flag'))
 
await Promise.all(promises)
const endTime = Date.now()
 
console.log(`100 concurrent evaluations took ${endTime - startTime}ms`)

Benchmark Testing


// Benchmark flag evaluation performance
async function benchmarkEvaluations() {
  const iterations = 10000
  const startTime = performance.now()
 
  for (let i = 0; i < iterations; i++) {
    await client.isEnabled('benchmark-flag')
  }
 
  const endTime = performance.now()
  const avgTime = (endTime - startTime) / iterations
 
  console.log(`Average evaluation time: ${avgTime.toFixed(3)}ms`)
}

Advanced Performance Features

Enterprise Performance Features

1. Dedicated Infrastructure

Private Edge Locations: Dedicated edge nodes for enterprise customers
Custom Caching Rules: Tailored caching strategies
Performance SLAs: Guaranteed performance levels

2. Advanced SDK Features

Streaming Connections: Persistent connections for real-time updates
Predictive Caching: ML-powered cache warming
Geographic Optimization: Region-specific performance tuning

Integration with Monitoring Tools

Application Performance Monitoring (APM)


// Integration with popular APM tools
import { trace } from '@opentelemetry/api'
 
const tracer = trace.getTracer('darkfeature-client')
 
const span = tracer.startSpan('feature-flag-evaluation')
const isEnabled = await client.isEnabled('feature-flag')
span.setAttributes({
  'flag.key': 'feature-flag',
  'flag.enabled': isEnabled,
})
span.end()

Custom Metrics


// Send custom performance metrics
client.on('evaluation', event => {
  // Send to your metrics system
  metrics.timing('flag.evaluation.duration', event.duration)
  metrics.increment('flag.evaluation.count')
})

Getting Help

If you’re experiencing performance issues:

Check Status Page: Visit status.darkfeature.com
Review Logs: Enable debug logging in your SDK
Contact Support: Reach out to our performance engineering team
Community: Join our Discord community for help

For enterprise customers, our performance engineering team can provide:

Custom performance audits
Optimization recommendations
Load testing assistance
Architecture reviews