Contract system. What are the available tools?

Question

Software design

Our young team ran into a problem. We spend a lot of time discussing what data should come from endpoints in our rest api. We want to solve this problem with the help of a system of contracts.
I heard about such when implementing a microservice architecture. For each service, we create our own contract - we indicate what data it receives, what it returns, and so on. In general, we describe the information on the microservice in as much detail as possible.
We want to apply a similar idea. The front parses the data it needs. Writes a contract for the required data structure, gives a verbal description of the contract, and sends it to the back. Beck corrects the data, if necessary, coordinating them with the front, indicates the data that he needs (also in the contract), coordinates everything with the front, and implements the contract. After the contract is implemented, the customer or contractor can write data for tests in it. That is, specify an array of test data and the result that they want to get
. In the future, we want to generate docks based on these contracts and even generate tests. There is a description, parameters, and test data for this.
Now I'm looking for tools. Maybe there are some utilities that can facilitate the writing of contracts and their coordination, maybe tests and docks are already generated in this way?