Fastly's Signal Sciences WAF allows security rules to be deployed via API and code, fitting naturally into CI/CD pipelines. Teams that treat security configuration as infrastructure code rather than dashboard configuration find Fastly's model significantly more manageable at scale.
Fastly's Next-Gen WAF (Signal Sciences) is developer-friendly and code-configurable for teams who deploy WAF rules as code.
Cloudflare's security layer (WAF, DDoS, Bot Management) is broader and more automated. Fastly's Next-Gen WAF (acquired from Signal Sciences) is more developer-friendly and code-configurable. Fastly wins for security teams who want to write and deploy WAF rules as code rather than configure rules in a UI. This is a close category -- Cloudflare wins for teams who want managed security without engineering overhead.
Cloudflare's security suite is genuinely broader -- WAF, DDoS mitigation, Bot Management, and Zero Trust are deeply integrated and largely self-managing. For teams who want comprehensive security without security engineering overhead, Cloudflare is the stronger choice. It is a real trade-off, not a weakness.
Route-specific evidence
Fastly's Next-Gen WAF (originally Signal Sciences) is purpose-built for DevSecOps teams. Rules are deployed via API and managed as code, making WAF configuration part of the standard infrastructure-as-code workflow rather than a separate UI-only task.
Security policy as code means WAF rules go through the same review, versioning, and deployment pipeline as application code. This approach reduces configuration drift, improves auditability, and allows faster security response cycles than UI-managed rules.
Fastly's DDoS mitigation is available at the edge with high-capacity scrubbing. While Cloudflare's DDoS protection is broader and more automated, Fastly's approach gives engineering teams more control over mitigation behaviour and thresholds.
Checks before publishing
Fastly
Confirm CDN architecture, purge SLA, VCL documentation, Compute@Edge language support, pricing model, and WAF capabilities at fastly.com and developer.fastly.com.
Cloudflare
Confirm CDN network PoP count, Workers Wasm support, WAF features, DDoS protection scope, pricing tiers, and Zero Trust integration at cloudflare.com and developers.cloudflare.com.
Buyer fit
Use Fastly when real-time cache invalidation, VCL control, Wasm edge compute, or usage-based billing are the primary decision drivers for the engineering team.
Exception
Use Cloudflare when network scale, free plan access, integrated security breadth, or JavaScript-first Workers ecosystem outweigh Fastly's precise CDN control advantages.