Best practices working with JSON in Go

I'm in the beginning of writing a chat app in Go and started wondering what is the best way working with JSON. I've read different articles and it seems like I have to create a different type for every action the client sends.

Lets say there are three actions:

NewMessage
DeleteMessage
EditMessage

To my understanding I have to create three types that match these actions. Something like this:

type Message struct {
	Action string `json:"action"`
	Data map[string]*json.RawMessage `json:"data"`
}

type MessageMeta struct {
	UserId int `json:"user_id"`
	ChannelID int `json:"channel_id"`
}

type NewMessageAction struct {
	MessageMeta
	Message string `json:"message"`
}

type EditMessageAction struct {
	MessageMeta
	MessageId int `json:"message_id"`
	Message string `json:"message"`
}

type DeleteMessageAction struct {
	MessageMeta
	MessageId int `json:"message_id"`
}

I come from Node.js world (although I don't want to compare the two) and to me it seems a bit too verbose to create and maintain a type for every action there is. What if there are hundreds of actions?

Go is a strongly typed programming language. There are no loose types like in JavaScript.

If you want a strong data type for each message, then you'll need to write a struct for each type. Otherwise you can unmarshal the message into a map[string]interface{} (for "generic" JSON objects) and work with that instead (which will require type assertions to convert the interface values into strong types).