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<aside> 💡 An API or application programmable interface is a software contract which defines the expectations and interactions of a piece of code exposed to external users. This includes the parameters, response, errors and API name.

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Important things to take care of :

• Naming Convention
• Parameter defining
• Response object definition
• Errors should be defined properly.

A lot of times we need to expose our APIs on an HTTP end point, for this we need to understand how HTTP response and request works.

Example of POST request

GET www.gkcs.tech/chat-mapping/getAdmins?groupID=123
**Request**
{
	"groupID" : "123"
}
**Response**
{
	"admins" : [{ 
								"id : 123",
								"name" : "xyz"}] 
}

set Admin(List<Admin> admin, string groupID) API should have no side-effects.

When response is too large, you can break it using two ways.

• Give responsibility to the client. Use pagination.
• Fragment the API.