workerd

What it is

workerd is the open-source runtime that executes Cloudflare Workers code, built on V8 with web-standard APIs such as fetch(). It can self-host Workers-style applications, run them locally during development and testing, or act as a programmable forward or reverse HTTP proxy. Configuration uses Cap'n Proto files with capability bindings that connect independently deployed nanoservices running in the same process. Developers building on the Workers platform use it to test locally or to run their code on their own machines.