1. mashape is a cloud API hub. It is a place to consume, distribute and manage private and public APIs. The mission is to to unlock and facilitate the distribution and consumption of data and services.

  2. ProgrammableWeb's API Directory is a great way to find the API you're looking for. It features great filtering tools and a massive database to choose from.

  3. API Integration Solution for Developers: 10x Faster • Less Maintenance • No Vendor-Lock-In. Use the same clean interface across multiple providers.

  4. 3scale is an API Management Platform that makes it easy to open, distribute, control, and monetize public, private or internal APIs.