All specifications for the Mesh APIs are documented at mesh-specifications in the OpenAPI 3.0 format (the successor to Swagger/OpenAPI 2.0). Because all interfaces are in this format, code (both for servers and clients) can be automatically generated using Swagger Codegen or OpenAPI Generator.
Check out mesh-sdk-go for an example of generating both a server and a client from rosetta-specifications.

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Specification Changes

If it is not possible to represent the abstractions used by a blockchain with the current specifications, please open an issue describing specifically what limitation is preventing you from implementing the Mesh APIs for a blockchain.