API is a set of routines, protocols, and tools for building software applications — **API** is a set of routines, protocols, and tools for building software applications

What is an API ?

5 min readDec 18, 2019

An application program interface (API) is a set of routines, protocols, and tools for building software applications. Basically, an API specifies how software components should interact thereby exposing business capabilities and services.

Characteristics of an API

APIs enable organizations to share information with external developers, business associates, and other teams within the same organization.
APIs allow you to expose some functions of a program or service in a managed and secure environment.
A high-quality API facilitates the development of applications by allowing different functionalities to be created independently while offering a complete set of capabilities for development.

Why API ?

APIs are needed for the following reasons

Supporting easier access to customers and partners.
Extending the reach to more channels and devices.

Surfacing of services for more flexibility.

Classification of APIs

External (public)

APIs are open to any developer who wants to sign up. Apps are more targeted towards end consumers

Partner (protected)

APIs are open to selected business partners. Apps are more targeted towards end consumers or business users.

Internal (private)

APIs are exposed only to existing developers within the enterprise. Apps are more targeted towards the employees of the enterprise.

API Lifecycle

The API lifecycle consists of four main components related to API management, which includes creating, running, managing, and securing APIs.

Creating APIs

Creating APIs involves developing and writing the API definition and implementation, identifying and debugging defects, and submitting the code and application through testing to ensure the functionalities work as required

Running APIs

Running APIs involves staging, packaging, and publishing the API.

Managing APIs

API management include the set of rules and conditions that govern the API; where, how, and with whom the API is shared; and if the API is meeting its stated purpose.

Monitoring APIs

Access control, monitoring, and logging are necessary functions of properly securing an API.

What makes an effective API design

APIs are excellent platforms for collaboration and innovation. APIs are the foundation for many web and mobile applications.

Ease of use

APIs with a good design are easy to learn and work with so that new users are able to quickly understand the operating governance structure.

Version support and documentation

High quality APIs have extensive and accessible documentation to aid developers as they work with the API. Examples of tools for api documentation swagger and apidocs

Aligned with the audience

APIs with a good design are aligned with their targeted audience. They have the correct interface type for the stated purpose, such as Representational State Transfer (REST) or Simple Object Access Protocol (SOAP) and allow developers to use the API for the intended end goal and within the requirements.

REST API

Representational State Transfer (REST) API is an architecture style for building resources on the web. Examples of resources for website include HTML documents, images, and script files

URI

To retrieve or update a resource, perform an action through HTTP methods, and to identify which resource to retrieve or update, REST uses a Uniform Resource Identifier (URI) to describe the network location of the resource.

HTTP methods

REST provides the following HTTP methods and for this article I will be using images from POSTMAN:

GET

The GET method is used to retrieve information from the server.

http://example.com?post=1

What simply happens here is a user makes a get request to a uri (http://example.com) and then parses a parameter of 1 to request for the first post

N:B : Each parameter is represented as a name-value pair (NAME = post , VALUE = 1)

POST

The POST method is used to post data to the server. In this case, the parameters are posted in the body of the request, not in the URI.

DELETE

The DELETE method is used to delete a resource from the server.

PUT

The PUT method is used to update a resource from the server.

OPTIONS
HEAD
LINK
UNLINK
PURGE
LOCK
TRACE
CONNECT

JSON

What is JSON?

JavaScript Object Notation (JSON) is a text format for structured data. Its syntax is derived from the object literals of JavaScript, according to the ECMA-262 ECMAScript language standard, third edition, which is the scripting language standard.

JSON Characteristics

JSON is a platform-neutral and language-neutral data format.
The main design goal of JSON is to provide a minimal, portable, textual data interchange format.
JSON is not a markup language. Unlike XML, it does not use descriptive tags to encapsulate its data.

JSON data types

JSON features the following data types:

String is a sequence of zero or more Unicode characters. For example: “Hello world!\n”.
Number includes an integer (0–9) or a fraction (0.5) or an exponent (-1.4719e7).
Object: An unordered collection of zero or more name-value pairs. Denoted by curly brackets . Example { “name” :’’Larry”, “age” : 22, “vegetarian” : false}

Array: An ordered sequence of zero or more values. Example

[

{

“id”: 24,

“name”: “Vito Fahey”,

“email”: “shayne83@example.net”,

“description”: null,

{

“id”: 37,

“name”: “Dr. Robb Leuschke II”,

“email”: “vincenzo90@example.com”,