Give access to a cacher server to SPI

We are making some changes to the way the Adobe CC connector supports authentication, to keep everything inside the Nuxeo infra.

David from SPI is asking us this:
We need an endpoint to call to store the code. There is a disconnect between the browser-based auth and the Connector client. The cache server fills that gap.

They are looking at storing the token there, they need the server to read and write the token.
This is their current approach:
They are currently using an external Redis provider. That provider won’t be available anymore as we want to keep everything inside our customer infra. They are looking at replacing it with something we own.
They use Redis to store the authentication token. A key value is created at the beginning of the process, and that key is what the client looks for when it polls Redis (through the Lambda) to find the authentication token.For example, the client first retrieves a key from the server. For illustration purpose, we can say the key is 123. That key is attached to the OAuth call that goes through Nuxeo. Once authentication is complete, and the browser is redirected to the callback URL, the new authentication token is stored in Redis at index 123. Meanwhile, the client (through a Lambda) is asking the server for the value at 123 until it receives a response. The server returns the auth token and deletes row 123.

Do you know how we can provide this cacher server?