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CloudFlare Workers

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CloudFlare Workers

How CloudFlare workers work?

  • Instead of running your code in containers, it runs it in what they call V8 isolates.
  • Although its fast and lightweight its functionality is quite limited.
  • It’s not the same as full-blown node.js that can be run in containers, but rather a separated V8 sandbox.
    • This means that you can only use built-in JS APIs, a subset of Web APIs (those known from browser environments), and provided Cloudflare Workers APIs.
    • So, e.g., you have to use Fetch API instead of http module, you can’t use native, CommonJS, and even ESM modules (even though it’s a browser-like V8 environment, ESM modules are disabled and can be used only through a bundler), you can’t use most of NodeJS or browser globals (like processwindowdocument), and DOM-related APIs.

Workers KV

  • KV provides really fast read speeds, thanks to running “on the edge,” which simply means closest to the client.
  • This, on the other hand, means that (unfortunately) any writes or deletes take longer to propagate (i.e., achieve “eventual consistency”) across the whole network.
  • Workers KV are great for any kind of intense-read scenarios like static websites, configs, and user data, where changes don’t happen often


Last updated: 2022-11-28