Web framework with shared memory structure

I want to make a REST Api with Kotlin with multiple worker that will have the same shared memory to get the data. It will be only read no write. I need to store the data in the RAM due to response time issue, it can’t be in a database.

I already have the same service in Python, but we can’t have shared memory and since we have more request we need to have more workers and the data is duplicated so we can’t scale well.

Do you have any recommandation about the REST framework I can use or doc I should look?