Optimization

Dynamic Site Acceleration, often shortened to DSA, is a set of techniques that CDNs use to optimize delivery of content that cannot be cached. Static files like images or scripts are easy to serve from edge servers, but dynamic pages, personalized dashboards, or API responses must still be fetched from the origin. DSA focuses on speeding up this unavoidable leg of the journey. Origins of DSA The concept appeared in the mid-2000s when early CDNs like Akamai began to bundle “application acceleration” products alongside their traditional caching services. Enterprises needed faster access to dynamic applications such as e-commerce checkouts or financial dashboards, which could not simply be cached at the edge. Providers promoted DSA as a premium add-on, often sold on top of a core CDN contract. Over time, most large vendors—Akamai, Limelight, and later Cloudflare and Fastly—added similar capabilities, though often under different names. ...

Synopsis This chapter describes how image and asset optimization works in a multi-CDN environment. It explains deterministic transform URLs, format negotiation with Accept and client hints, parity across vendor image engines, cache identity and validation, quality targets, rollout controls, and telemetry that proves user visible improvements without fragmenting caches or breaking links. Scope and objectives Many CDNs provide on the fly transforms for images and lightweight assets. Typical operations include resize, crop, format conversion, quality selection, and color space handling. Multi-CDN adds a requirement that identical requests produce identical bytes or at least identical perceptual quality, and that cache identity does not drift between providers. The objective is predictable output, stable cache behavior, and measurable gains in transfer size and rendering time. ...