Which is better — modular monolith or microservices for a chess service?

For a chess service, it is better to choose a modular monolith, especially in the initial stage. Chess is a fairly specific domain with closely related components (game logic, user management, ratings, etc.), and a modular monolith will make it easier to manage the code, develop functionality faster, and test more easily.

Microservices make sense when the system scales horizontally, and different parts of the application require independent deployment and scaling. In the case of a chess service, this might be excessive and complicate the architecture without clear benefits.

An example structure of a modular monolith in Go:

package main

import "fmt"

// Game logic module
func playChess() {
    fmt.Println("The game has started")
}

// User management module
func manageUsers() {
    fmt.Println("Managing users")
}

func main() {
    playChess()
    manageUsers()
}

Thus, a modular monolith provides a balance between structure and simplicity.