Because V8's low-overhead tenant isolation is fundamental to how Cloudflare Workers works[1], and without it it would be a completely different product with wor

Because V8's low-overhead tenant isolation is fundamental to how Cloudflare Workers works[1], and without it it would be a completely different product with worse performance. This means it can only support JavaScript and WebAssembly. You can run it locally[2], and efforts are underway to standardize much of it so that the same code can run on Workers, Node.js, and Deno[3]. The Workers runtime is also open source[4], although in practice this is likely to be less useful for most use cases than just using one of the other JavaScript runtimes if you're self-hosting. [1] https://developers.cloudflare.com/workers/learning/how-workers-works/ https://developers.cloudflare.com/workers/learning/how-worke... [2] https://developers.cloudflare.com/pages/platform/functions#develop-and-preview-locally https://developers.cloudflare.com/pages/platform/functions#d... [3] https://wintercg.org/ https://wintercg.org/ [4] https://github.com/cloudflare/workerd https://github.com/cloudflare/workerd