CDN & Caching

Sherpa.sh provides high-performance content delivery and caching through our global CDN infrastructure, powered by bunny.net's industry-leading network. Our CDN automatically optimizes content delivery for your applications while providing flexible caching controls for different deployment scenarios.

Performance Advantages on Sherpa.sh

Global Network Infrastructure

Our CDN delivers industry-leading performance with:

200+ Points of Presence (PoPs) strategically located worldwide
25.45ms average global latency - significantly lower than competitors
95% cache hit ratio ensuring optimal content delivery
100Gbit uplinks with NVMe storage at major PoPs

Regional Performance Comparison

Sherpa.sh CDN consistently outperforms legacy CDN providers across all major regions:

North America: 15-20ms average latency
Europe: 18-25ms average latency
Asia-Pacific: 22-28ms average latency
Latin America: 25-35ms average latency
Africa: 30-45ms average latency

How Our Caching Works

Framework-Aware Caching

When deploying full-stack frameworks, Sherpa.sh intelligently listens to your framework's default cache-control headers and configures caching settings accordingly. We optimize these settings based on established best practices for each framework.

Next.js Example:

Below you will find and example of how our framework aware caching performs on a nextjs app. This intelligent caching occurs for all our supported frameworks

Static Assets

Path: /_next/static/*
Cache-Control: public, max-age=31536000, immutable
Purpose: Cached for 1 year to improve performance.

API Routes

Path: /api/*
Cache-Control: no-cache, no-store, must-revalidate
Purpose: Not cached by default to ensure data is always fresh.

Server-side Rendered Pages

Cache-Control: public, max-age=0, must-revalidate
Purpose: Short cache life with revalidation to update content dynamically.

Static Pages

Cache-Control: public, max-age=3600, stale-while-revalidate=86400
Purpose: Cached with background updates to allow fresh content while ensuring availability.

Our system automatically recognizes these patterns and applies optimal caching strategies:

Static assets: Long-term caching with immutable flag
API endpoints: Bypassed from CDN cache
Dynamic pages: Smart caching with background refresh
Image optimization: Automatic format conversion and caching

Global Key-Value Store

Sherpa.sh includes a global KV store that serves as the backend cache for various frameworks. This is separate from our CDN caching layer and provides:

Low-latency data access across all deployment regions
Automatic replication for high availability
Framework integration for session storage, API caching, and more
Edge computing support for serverless functions

Note: This KV store is distinct from CDN caching and focuses on application-level data storage.

Docker Deployment Caching

Manual Cache Header Configuration

When deploying Docker containers, you must set cache-control headers manually since containerized applications don't have framework-specific defaults.

Setting Cache Headers in Docker Applications:

# Example: Node.js Express application
FROM node:18-alpine

COPY . .

RUN npm install

EXPOSE 3000

CMD ["node", "server.js"]

// server.js - Manual header configuration

app.use(
  '/static',
  express.static('public', {
    maxAge: '1y',
    etag: false,
    lastModified: false
  })
);

app.get('/api/*', (req, res) => {
  res.set('Cache-Control', 'no-store');
  // API logic here
});

app.get('/', (req, res) => {
  res.set('Cache-Control', 'public, max-age=3600, stale-while-revalidate=86400');
  res.send('Hello World');

Cache-Control Headers Reference

Understanding when and how to use different cache-control directives is crucial for optimal performance. Here's a comprehensive guide:

Cache-Control Policy Guidelines

1. Static Assets (CSS, JS, Images with Versioning):

Cache-Control: public, max-age=31536000, immutable

2. HTML Pages with Dynamic Content:

Cache-Control: public, max-age=3600, stale-while-revalidate=86400

3. API Responses That Change Frequently:

Cache-Control: public, max-age=300, must-revalidate

4. Sensitive or User-Specific Content:

Cache-Control: private, max-age=0, no-cache

5. Content That Should Never Be Cached:

`Cache-Control: no-store, no-cache, must

Key Directives Explained:

public: Cacheable by CDN and browsers
private: Only cacheable by browsers
max-age: Cache lifetime in seconds
stale-while-revalidate: Serve stale content while updating
immutable: Content never changes (perfect for versioned assets)
no-store: Never cache anywhere

For detailed information about HTTP caching headers, refer to the MDN Cache-Control documentation.

CDN Configuration Options

Automatic CDN Deployment

Sherpa.sh automatically places a CDN in front of every deployment by default. This provides:

Global content distribution across 200+ edge locations
Automatic SSL termination and certificate management
DDoS protection and security filtering
Image optimization and format conversion

Docker CDN Recommendations

For Docker deployments, you can disable CDN if needed, though this is typically recommended only when:

You're unsure whether your framework sets appropriate cache-control headers
Your application requires direct server connections
You're implementing custom caching logic

Best Practice: Keep CDN enabled and configure proper cache headers instead of disabling CDN entirely.

Advanced Caching Features

Sherpa.sh automatically implements sophisticated caching optimizations behind the scenes to maximize performance and reliability. Here's what happens under the hood when your application is deployed.

Smart Cache Intelligence

Automatic File Type Detection

When your application serves content, our CDN automatically analyzes each request and determines the optimal caching strategy:

What happens internally:

File extensions and MIME types are analyzed in real-time
Static assets (CSS, JS, images) receive aggressive caching
Dynamic endpoints are intelligently bypassed
Binary files are optimized for streaming delivery

Query String Normalization

Our system automatically sorts query parameters to improve cache hit rates:

# These requests are treated as identical:
GET /api/resize?width=200&height=100&format=webp
GET /api/resize?format=webp&height=100&width=200
GET /api/resize?height=100&width=200&format=webp
# Result: Single cached response serves all three requests

Benefits for developers:

Higher cache hit rates without code changes
Reduced origin server load
Consistent response times regardless of parameter order

Intelligent Cache Variations

Browser Capability Detection

The CDN automatically detects browser capabilities and serves optimized content:

# Modern browser request:
# Accept: image/avif,image/webp,image/*
# Serves: optimized AVIF format (90% smaller) Cache-Key: image.jpg:avif-support

# Legacy browser request: 
# Accept: image/*
# Serves: standard JPEG format Cache-Key: image.jpg:no-avif-support

Device-Aware Caching

Content is automatically optimized based on device characteristics:

# Mobile device:User-Agent: Mozilla/5.0 (iPhone; CPU iPhone OS...) # Serves: Mobile-optimized images and CSS
# Desktop device:User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS...)  # Serves: High-resolution desktop assets

Geographic Optimization

Content delivery is optimized based on user location:

# User in Europe:
# Serves from Amsterdam PoP (12ms latency)
# Includes region-specific optimizations

# User in Asia:  
# Serves from Tokyo PoP (8ms latency)
# Applies Asia-Pacific performance tweaks

Resilient Content Delivery

Error Response Protection

The CDN automatically protects your origin server from cascading failures:

# Origin server returns 500 error 
HTTP/1.1 500 Internal Server Error

# CDN behavior:
1. Caches error response for 5 seconds
2. Serves cached error to subsequent requests
3. Prevents origin server overload during incidents
4. Automatically retries after cache expiration

Stale Content Serving

When your origin server is unreachable or updating, users still receive content:

# Scenario 1: Origin server offline
Origin Status: Connection refused
CDN Response: Serves last known good version Cache-Control: stale-while-revalidate

# Scenario 2: Content being updated
Origin Status: Updating cache in background
CDN Response: Serves current cached version immediately
Update Status: New content ready for next request

Real-world impact:

99.9% uptime even during origin server issues
Zero-downtime deployments
Seamless user experience during maintenance

Performance Optimizations

Video Content Handling

Large media files receive special treatment:

# Video file request with byte range:
GET /video.mp4Range: bytes=1000000-2000000
# CDN behavior:
1. Splits file into 5MB chunks during first request
2. Caches chunks independently  
3. Serves partial content without hitting origin
4. Enables video scrubbing for uncached content

Multi-Layer Caching

Your content benefits from multiple caching layers:

Request Flow:
Browser Cache (immediate)    
 ↓ (cache miss)Edge PoP Cache (5-25ms) 
    ↓ (cache miss)  Regional Cache (25-50ms)  
        ↓ (cache miss) Origin Server (50-200ms)

Developer Benefits

Zero Configuration Required

All optimizations work automatically:

No cache headers to configure for frameworks
Automatic performance improvements
Self-tuning based on traffic patterns

Built-in Best Practices

The system implements industry standards:

Proper cache invalidation strategies
Optimal TTL values for different content types
Automatic security header injection

Troubleshooting Common Scenarios

Low Cache Hit Rates

The system automatically adjusts when hit rates drop:

Analyzes traffic patterns
Adjusts cache TTL values
Optimizes query string handling

Content Update Delays

Stale content serving ensures smooth updates:

New content propagates in background
Users never see loading states
Automatic cache purging when needed

This intelligent caching layer operates transparently, requiring no configuration while delivering maximum performance benefits for your applications.

PreviousContinuous Delivery NextPromotions & Rollbacks

Last updated 21 days ago