How to Test Cloudflare Workers Using Only Vitest Without Miniflare

A developer added over 3,000 lines of tests to a Cloudflare Worker without using Miniflare or any Workers runtime simulation. The approach relies on Vitest with a standard Node environment and vi.stubGlobal to mock the global fetch function. Since Cloudflare Workers are essentially JavaScript functions that accept a Request and return a Response, most logic can be unit-tested without Cloudflare's runtime. The method proved especially useful for catching critical bugs, such as cache headers accidentally being applied to affiliate tracking routes, which would silently break click recording. The author argues this setup is faster and simpler than runtime simulation, and better suited to catching production regressions early.