Mock sample for your project: Qualpay Payment Gateway API

Use the Taxonomy API to discover the most appropriate eBay categories under which sellers can offer inventory items for sale, and the most likely categories under which buyers can browse or search for items to purchase. In addition, the Taxonomy API provides metadata about the required and recommended category aspects to include in listings, and also has two operations to retrieve parts compatibility information.

Send an SMS with verification code and a custom message for authentication purpose. It helps merchants to minimize chargebacks and fraud for various kinds of payment method, such as credit card, paypal, cod and so on. Please visit https://www.fraudlabspro.com to learn more.

Use the Fulfillment API to complete the process of packaging, addressing, handling, and shipping each order on behalf of the seller, in accordance with the payment method and timing specified at checkout.

Use this api to fetch information to Amazon products and more.

A product library is a representation of all the items that can be
displayed, put in a shopping cart and sold to a customer. Items may be
either producs or discounts.
A product is a synthetic construct, wrapping one or more variants (which is
the actual item being sold) Variants expresses different variations of
properties such as for example price, size or color. A discount will reduce
the total amount charged in a shopping cart. It can be used per item line,
or on the whole cart. It may reduce the affected amount by a percentage, or
by a fixed amount.
Together, the above types of entities makes up a complete library. The
library can be fetched as a whole through the library endpoint, where each
consecutive change applied to the library is available. Once the full
library is retrieved, only later events needs to be fetched to keep the
client up to date with the server
All path patterns "/organizations/{organizationUuid}/" can be replaced
with "/organizations/self/" for convenience as all endpoints are for
authorized users.

Note: This is a (Limited Release) API available only to select developers approved by business units. The Logistics API resources offer the following capabilities: shipping_quote – Consolidates into a list a set of live shipping rates, or quotes, from which you can select a rate to ship a package. shipment – Creates a "shipment" for the selected shipping rate. Call createShippingQuote to get a list of live shipping rates. The rates returned are all valid for a specific time window and all quoted prices are at eBay-negotiated rates. Select one of the live rates and using its associated rateId, create a "shipment" for the package by calling createFromShippingQuote. Creating a shipment completes an agreement, and the cost of the base service and any added shipping options are summed into the returned totalShippingCost value. This action also generates a shipping label that you can use to ship the package. The total cost of the shipment is incurred when the package is shipped using the supplied shipping label. Important! Sellers must set up a payment method via their eBay account before they can use the methods in this API to create a shipment and the associated shipping label.

The DocuSign REST API provides you with a powerful, convenient, and simple Web services API for interacting with DocuSign.

Service for providing information to sellers about their listings being non-compliant, or at risk for becoming non-compliant, against eBay listing policies.

Documentation of the Billbee REST API to connect a Billbee account to external aplications.
Endpoint
The Billbee API endpoint base url is https://app.billbee.io/api/v1
Activation
You have to enable the API in the settings of your Billbee account. In addition you need a Billbee API Key identifying the application you develop. To get an API key, send a mail to [email protected] and send us a short note about what you are building.
Authorization & security
Because you can access private data with the Billbee API, every request has to be sent over https and must
Contain a valid API Key identifying the application/developer. It has to be sent as the HTTP header X-Billbee-Api-Key
Contain a valid user login with billbee username and api password in form of a basic auth HTTP header
Throttling
Each endpoint has a throttle of max 2 requests per second per combination of API Key and Billbee user.
When you exceed these 2 calls, the API will return a HTTP 429 status code

API2Cart