Mock sample for your project: DocuSign REST API

The Metadata API has operations that retrieve configuration details pertaining to the different eBay marketplaces. In addition to marketplace information, the API also has operations that get information that helps sellers list items on eBay.

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.

Endpoint Structure
All URLs are in the format:
More
Jumpseller API wrapper provides a public Ruby abstraction over our API;
Apps Page showcases external integrations with Jumpseller done by technical experts;
Imgbb API provides an easy way to upload and temporaly host for images and files.

Just Eat API
Just Eat offers services for our various business partners and our consumer applications.
How you interact with the API depends on the services you wish to interact with.
Security
HTTPS
All api calls and callbacks require HTTPS. Your service will need a valid SSL certificate and be accessible via the standard SSL port (port 443).
Making an API request
Some API calls require an API key, to authenticate the partner calling the API.

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.

This is the koomalooma Partner API. koomalooma is the first Loyalty BPaaS (Business Process as a Service) for mobile and web companies. With koomalooma merchants issue points for actions their customers / users make on your mobile or web store, for example a purchase or a referral. koomalooma takes care of all the rest, from signing up users, keeping track of points and delivering rewards in over 80 countries. koomalooma offers an easy to integrate API and web backend to configure loyalty campaigns and track performance. You can find more at http://support.koomalooma.com

reverb

papinet API is a global initiative for the Forst and Paper supply chain.

The shop API empowers developers to build amazing new apps or websites using Zalando shop data and services.