Bluemix is IBM's cloud platform that provides infrastructure as a service (IaaS), platform as a service (PaaS), and software as a service (SaaS). It offers public, dedicated, and local deployment options across global data centers. Bluemix provides built-in programming languages and runtimes, services from its catalog that extend app functionality, and tools for DevOps. It allows hosting your own apps and services or using prebuilt ones from IBM like Watson cognitive APIs.