Kong is the more common of the two in our index: it runs on 20 websites against 3 for IBM DataPower. Counts come from real scans, not vendor claims.
IBM DataPower Gateway is a single multi-channel gateway designed to help provide security, control, integration and optimized access to a full range of mobile, web, application programming interface (API), service-oriented architecture (SOA), B2B and cloud workloads.
Kong is an open-source API gateway and platform that acts as middleware between compute clients and the API-centric applications.
Want to know which one a particular site uses? Look it up and see its whole stack, or compare two sites side by side.