# CDN Handbook

> A practical, independent handbook about content delivery networks, HTTP caching, CDN providers, security and multi-CDN architecture.

Provider profiles cover public CDNs, image/video optimization, enterprise event delivery, broadcast transport and CDN software. Each profile identifies its product scope, alongside cloud, storage, DNS and management offerings. Historical brands are retained for context; an acquisition or rebrand does not by itself establish that a service closed. An unlisted capability means its support is unconfirmed, not that it is unsupported.

Cost estimates depend on traffic pattern, region, requests, cache misses and plan eligibility. Compare the same workload and check the provider's current terms before purchasing. Maps show named locations with an identified scope; telecom reach and cloud regions are not automatically CDN cache locations. Each profile includes a Sources reveal for supporting references.

## Provider research and tools

- [Provider catalogue](https://www.cdnhandbook.com/providers/): Browse current services and historical provider listings.
- [Compare providers](https://www.cdnhandbook.com/compare/): Select two providers for capabilities, architecture and pricing. Shared traffic estimates use supported tariffs; media credits, event licensing and deployment contracts have separate pricing guidance. Pair selection happens in the browser.
- [CDN cost calculator](https://www.cdnhandbook.com/calculator/): Workload presets, advanced traffic inputs, supported public tariffs and manual quotes.
- [Choosing a CDN](https://www.cdnhandbook.com/guides/choose-cdn/): Evaluation criteria and practical tradeoffs.
- [CDN pricing methodology](https://www.cdnhandbook.com/guides/cdn-pricing-methodology/): How to compare billing meters and understand estimate limits.

## Foundations and implementation

- [CDN fundamentals](https://www.cdnhandbook.com/cdn/): Delivery architecture and common concepts.
- [Multi-CDN](https://www.cdnhandbook.com/multicdn/): Routing and operating more than one delivery network.
- [Cache-Control](https://www.cdnhandbook.com/guides/cache-control/): Browser and shared-cache policy.
- [Cache keys and Vary](https://www.cdnhandbook.com/guides/cache-keys-vary/): Which requests share cached objects.
- [Purging cached content](https://www.cdnhandbook.com/guides/purge/): Invalidation and freshness tradeoffs.
- [HTTP/3 and QUIC](https://www.cdnhandbook.com/guides/http3-quic/): Transport behavior and deployment considerations.
- [Mainland China delivery](https://www.cdnhandbook.com/guides/cdn-mainland-china/): Regional requirements and delivery constraints.

## Optional

- [Glossary](https://www.cdnhandbook.com/glossary/): Definitions used throughout the handbook.
- [Sitemap](https://www.cdnhandbook.com/sitemap.xml): Complete index of public pages.