MetaMate is a semantic service bus open source that provides a unified interface for accessing diverse sources of data, including APIs and blockchains. It also supports websites, peer-to-peer networks, and other web services. MetaMate allows seamless interaction with different services by mapping vendor-specific data to an abstract schema graph. The community-driven approach of MetaMate allows contributors to create new types and fields. This ensures that the system is updated with real-world data. The platform's type-system is derived from widely used data transmission technologies, such as GraphQL and gRPC. It also incorporates Thrift and OpenAPI to facilitate compatibility with different protocols. MetaMate enforces the backward compatibility of services and applications that are built on its platform programmatically. Using its command-line, it can also generate SDKs that are tailored to the specific needs of a project, and only cover the subsets of the schema graph that are desired.