Serving Cache using API Web Service

I am developing a LFU Cache in Golang and want to use same in a Python/Flask URL Shortener to store data in cache in form on Key Pair either in (URL, CODE) or (sha256(URL), CODE). I am thinking of using Cache in GoLang using API(JSON), the data will be on Primary Memory, so Not Persistent. How should I handle multiple concurrent requests to Cache that might Hit or Miss? I am thinking of using a Web Service as it can be deployed as a service and might not be using up App's Memory.
Thanks!