Mock sample for your project: shipstation API

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.

The Marketing API offers two platforms that sellers can use to promote and advertise their products: Promoted Listings is an eBay ad service that lets sellers set up ad campaigns for the products they want to promote. eBay displays the ads in search results and in other marketing modules as SPONSORED listings. If an item in a Promoted Listings campaign sells, the seller is assessed a Promoted Listings fee, which is a seller-specified percentage applied to the sales price. For complete details, see Promoted Listings. Promotions Manager gives sellers a way to offer discounts on specific items as a way to attract buyers to their inventory. Sellers can set up discounts (such as "20% off" and other types of offers) on specific items or on an entire customer order. To further attract buyers, eBay prominently displays promotion teasers throughout buyer flows. For complete details, see Promotions Manager. Marketing reports, on both the Promoted Listings and Promotions Manager platforms, give sellers information that shows the effectiveness of their marketing strategies. The data gives sellers the ability to review and fine tune their marketing efforts. Important! Sellers must have an active eBay Store subscription, and they must accept the Terms and Conditions before they can make requests to these APIs in the Production environment. There are also site-specific listings requirements and restrictions associated with these marketing tools, as listed in the "requirements and restrictions" sections for Promoted Listings and Promotions Manager. The table below lists all the Marketing API calls grouped by resource.

The Charity API allows third-party developers to search for and access details on supported charitable organizations.

One API serving data spanned across multiple verticals

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.

dropX.io API provides programmatic access to the e-commerce intelligence data.

reverb

This API is used to retrieve seller payouts and monetary transaction details related to those payouts.

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.

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.

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

The Feed API lets sellers upload input files, download reports and files including their status, filter reports using URI parameters, and retrieve customer service metrics task details.