Client/Server Application with Offline Ability

I am currently struggling to get the architecture/design for my application right. I want to create a Client/Server application that uses an Rest-API with specific requests (like CreateCustomer, ReadCustomer).

Example: CreateCustomer: The server deals with the CustomerDto and stores it in database. On the other side, the client should have access to this customer-object, even if the internet connection fails right after sending the create-request.

I want to implement something like a cache layer, that actually tries to retrieve data from the server, but if it cannot access it (lost connection), it just uses the offline data.

Basically: If the client is offline, the user shall be able to still create customers (and further use them in other tasks like orders). So I want to create a layer between client and api that takes care of this.

Does anyone know a suitable framework or pattern to accomplish this? Or is there any other solution that I haven't thought of?

kind regards