How do I create an API for dropshipping

Hi, Im listing products on my website from my drop shipping website which takes hours, my drop shipper in China now accepts API do list products and process orders, what do I do to place the API key on my site, Heres the info from my Drop shipper site, Thanks

Introduction

Our API provides you the possibility to securely connect our system with your website to automate certain dropshipping activities such as listing products and processing orders.

It offers an efficient way of communication by saving you the time to browse the Chinavasion website for download category/product information and listing them on your website. In addition, you don't have to add products to the cart and go through the checkout process manually. As there is no session, every API call will contain an unique customer identification key.

Orders can be automatically paid when your account has store credit deposited. An alternative way is to receive email notifications to pay for orders manually once created.

We apply JSON as the data collection format for communication through API using HTTP POST method. Each Request (Input) has to be formatted in JSON in a predefined manner before posting it to a dedicated URL. The resulting Response (Output) will also be displayed in a predefined format. The definition of Request and Response JSON format is defined precisely in the help of each API call.

There are two types of API requests: queries and actions. Query requests return data to customer, but will not modify anything in the Chinavasion system. In contrast, action requests do perform updates in the system and return data as the result of the action.

Query calls:

getCategory - This call will return a list of product categories, including both top-level categories and all subcategories. There is also an option to include additional detailed content if required.
getProductList - This call will return a list of products based on specified category name(s). The returned result includes product IDs, model codes, product names, product URLs, pictures and other product related details. Category names can be retrieved by the query call 'getCategory' above.
getProductDetails - This call will return a single product's details based on the specified product ID or model code. There is an option to show the price in a specified currency.
getAddress - This call will return a list of addresses which are stored in the address book of your Chinavasion Account.
getOrderList - This call will return a list of order with details. The returned result includes order ID, order status, shipping information, order amount, address and order product details. There is a pagination to define the size of the result set by the specified start order ID and number of orders to be returned.
getOrderDetails - This call will return a single order with details. The returned result includes order ID, order status, shipping information, order amount, address and order product details. Input parameters specify the which order details are requested.
getCreditBalance - This call will return the current credit balance on customer account; the result will be a list of amount in different currencies.
getPrice - This call will return a set of product prices with list of different shipping options based on the specified products with quantity, currency, socket and country. The returned shipping options include shipping method, shipping price and estimated delivery days.
Action calls:

createAddress - This call will create and store new address entry in the address book in your Chinavasion Account.
createOrder - This call will create new order, which will be automatically paid by balance credit if there is enough. Other payment methods are also accepted but have to be processed manually. Available shipping methods can be retrieved by another query call - getPrice. Either product ID or model code is accepted for order details with required quantity. This is also an option to leave comment or special request note.

You are not supposed to create an API if you want to connect to your dropshippers API. You create a client side integration.

Have a look at the wiki article how to create an order module. It will will be triggered on certain events.

hmmm this is a very nice information thanks for sharing.

How to creat such api for dropshipping like easync or others?

Google is your friend
https://lmgtfy.com/?q=how+to+create+a+rest+api+in+php

But I would recommend hiring a developer