Fastly

Fastly is an edge cloud platform providing content delivery network (CDN), DDoS protection, web application firewall (WAF), and edge computing capabilities. Unlike traditional CDNs with slow configuration propagation, Fastly deploys changes globally in seconds via its real-time architecture. With Compute@Edge serverless platform and VCL (Varnish Configuration Language) scripting, developers can run custom logic at the edge—authentication, routing, A/B testing, or API composition—without roundtrips to origin servers.

Best for: High-traffic websites, media companies, and API providers who need low-latency content delivery with instant configuration updates and advanced edge logic. Particularly valuable for organizations requiring real-time cache purging, instant SSL certificate deployment, or custom edge behavior beyond basic CDN capabilities. Popular with e-commerce (Shopify uses Fastly) and streaming platforms.

Common Questions

What makes Fastly different from CloudFront or Cloudflare?
Fastly emphasizes instant configuration propagation (seconds vs. 10-30 minutes for CloudFront), programmable edge logic via VCL or Compute@Edge, and detailed real-time analytics. Cloudflare focuses on security with expansive free tier; CloudFront integrates deeply with AWS ecosystem. Fastly suits teams needing advanced customization and instant cache control; Cloudflare works for security-first needs; CloudFront fits AWS-native architectures.

What is Compute@Edge?
Compute@Edge is Fastly's serverless edge computing platform that runs WebAssembly at the network edge (similar to Cloudflare Workers). Write functions in Rust, JavaScript, Go, or other languages that compile to WASM, then deploy globally to execute milliseconds from users. Use cases: authentication at edge, API aggregation, personalization, request/response transformation, geolocation-based routing.

How does Fastly pricing work?
Fastly charges based on bandwidth (data transfer out), number of requests, and optional add-ons like image optimization or security features. Pricing starts around $0.12/GB bandwidth (decreasing with volume) and $0.0075 per 10,000 requests. Most organizations spend $500-$5,000+/month depending on traffic volume. Enterprise pricing offers volume discounts and custom SLAs.

What is instant purging?
Fastly's instant purge capability clears cached content globally within 150ms. When you update content (article, product page, API response), trigger a purge via API and users worldwide see fresh content within milliseconds. This enables "cache everything" strategies with aggressive TTLs without serving stale content. Supports purge by URL, surrogate key (tag), or entire cache.

Pricing & Plans

Fastly CDN:

• Pay-as-you-go: $0.12/GB bandwidth, $0.0075 per 10,000 requests
• Volume discounts: Pricing decreases as usage scales (custom contracts for TB+ monthly)

Compute@Edge:

• $0.45 per million requests
• $0.048 per GB-second of compute time

Image Optimizer:

• $0.075 per 1,000 optimizations

Security Add-ons:

• Next-Gen WAF: Custom pricing (typically $2,000-$5,000+/month minimum)
• DDoS Protection: Included in all plans

Typical costs: $500-$2,000/month for moderate traffic; $5,000-$50,000+/month for high-volume sites.

Limitations

• Costs scale with traffic: High-bandwidth sites (video streaming, software downloads) can incur significant costs at $0.08-$0.12/GB. Requires cost monitoring and optimization.
• Steeper learning curve: VCL programming and Compute@Edge require more expertise than simpler CDNs. Configuration is powerful but complex compared to one-click CDN services.
• Less generous free tier: Unlike Cloudflare's extensive free tier, Fastly is pay-as-you-go from the start. Better for companies with budget, not hobbyists or small sites.

Getting Started

1. Sign up at fastly.com (credit card required, pay-as-you-go pricing)
2. Create a service and configure origin server (your web server or S3 bucket)
3. Configure domain and SSL certificate (auto-provisioned via Let's Encrypt)
4. Set caching rules via VCL snippets or UI
5. Update DNS to point to Fastly's edge servers (CNAME record)
6. Test content delivery and caching behavior
7. Monitor traffic and costs in real-time dashboard
8. Optional: Deploy edge logic via Compute@Edge for advanced use cases

Use Fastly's VCL boilerplate templates for common patterns (redirects, authentication, bot blocking). Start simple, then add edge logic as needed.