How do content delivery networks (CDNs) enhance the performance and availability of web applications, and what are the key considerations when integrating a CDN?

CDNs enhance performance by caching content at edge servers close to users, reducing latency and load on the origin server. They improve availability by distributing traffic and providing redundancy. Key considerations when integrating a CDN include selecting the appropriate CDN provider, configuring caching rules, handling cache invalidation, ensuring secure content delivery with HTTPS, and monitoring CDN performance to optimize content delivery strategies.