Mock sample for your project: Just Eat UK API

The Analytics API provides data and information about a seller and their eBay business. The resources and methods in this API let sellers review information on their listing performance, metrics on their customer service performance, and details on their eBay seller performance rating. The three resources in the Analytics API provide the following data and information: Customer Service Metric – Returns data on a seller's customer service performance as compared to other seller's in the same peer group. Traffic Report – Returns data that shows how buyers are engaging with a seller's listings. Seller Standards Profile – Returns data pertaining to a seller's performance rating. Sellers can use the data and information returned by the various Analytics API methods to determine where they can make improvements to increase sales and how they might improve their seller status as viewed by eBay buyers. For details on using this API, see Analyzing seller performance.

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

Note: This is a (Limited Release) API available only to select developers approved by business units. This API allows third-party developers to search for and retrieve details about eBay deals and events, as well as the items associated with those deals and events.

The Account API gives sellers the ability to configure their eBay seller accounts, including the seller's policies (the Fulfillment Policy, Payment Policy, and Return Policy), opt in and out of eBay seller programs, configure sales tax tables, and get account information. For details on the availability of the methods in this API, see Account API requirements and restrictions.

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

https://www.beanstream.com/api/v1

The Negotiations API gives sellers the ability to proactively send discount offers to buyers who have shown an "interest" in their listings. By sending buyers discount offers on listings where they have shown an interest, sellers can increase the velocity of their sales. There are various ways for a buyer to show interest in a listing. For example, if a buyer adds the listing to their Watch list, or if they add the listing to their shopping cart and later abandon the cart, they are deemed to have shown an interest in the listing. In the offers that sellers send, they can discount their listings by either a percentage off the listing price, or they can set a new discounted price that is lower than the original listing price. For details about how seller offers work, see Sending offers to buyers.

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.

Maintaining up-to-date inventory for your items on Walmart.com ensures a great experience for your customers and greater sales opportunities for you.

The Browse API has the following resources: itemsummary: Lets shoppers search for specific items by keyword, GTIN, category, charity, product, or item aspects and refine the results by using filters, such as aspects, compatibility, and fields values. (Experimental) searchbyimage: Lets shoppers search for specific items by image. You can refine the results by using URI parameters and filters. item: Lets you retrieve the details of a specific item or all the items in an item group, which is an item with variations such as color and size and check if a product is compatible with the specified item, such as if a specific car is compatible with a specific part. Provides a bridge between the eBay legacy APIs, such as Finding, and the RESTful APIs, which use different formats for the item IDs. (Experimental) shoppingcart: Provides the ability for eBay members to see the contents of their eBay cart, and add, remove, and change the quantity of items in their eBay cart. Note: This resource is not available in the eBay API Explorer. The itemsummary, searchbyimage, and item resource calls require an Application access token. The shoppingcart resource calls require a User access token.