Yes, a Cloudflare Worker is actually one of the better options for this use case. It’s lightweight, stateless, fast, and avoids maintaining a full backend server. You can use it to intercept the Vapi request, inject the reasoning_effort parameter, forward it to Azure OpenAI, and return the response transparently. It also gives you good security controls like secret management, rate limiting, IP filtering, and request validation with very little operational overhead. For this kind of middleware, Cloudflare Workers are usually cleaner and easier to maintain than spinning up a separate Node server or container.