Mashape is described as 'Free API Management Platform & Marketplace'. There are seven alternatives to Mashape, not only websites but also apps for a variety of platforms, including Mac, Windows, Linux and Self-Hosted solutions. The best alternative is KrakenD, which is both free and Open Source. Other great sites and apps similar to Mashape are WSO2 API Manager (Free, Open Source), Algorithmia (Freemium), Apigee (Freemium) and macgyver (Paid).
KrakenD is an ultra performant API Gateway with middlewares or it's also known as a *Backend For Frontend* as it sits between the client (frontend) and source servers (backends) offering a custom API that provides only the information that the UI needs.
SEOBOTS.io is an on-demand bot marketplace for data analysis, marketing, web automation and much more. Developers are able to upload and sell their scripts to users who can then run them in the cloud and view the data online or export it.
Nevatech Sentinet is the only enterprise class API Management and SOA Governance platform written in .NET that is available for On-Premise, Cloud and Hybrid environments. It connects, mediates and manages interactions between services across the enterprise or in the cloud.