webfakes

webfakes is an R package that provides a lightweight framework for creating fake web servers to test HTTP-related code. It uses the embedded civetweb server to run web apps directly in your R process.

The package solves the problem of testing HTTP clients and APIs without relying on external services. It includes a complete web framework for defining custom handlers in R, comes with a built-in httpbin-like app for common testing scenarios, and supports concurrent requests through multi-threading. Since the server runs in-process, it avoids firewall issues and allows you to test network code reliably and quickly.