Hyperledger Composer is a platform for accelerating the development process of Business Network Application. Why is it deprecated and what are the alternatives to composer for development of BNAs?
According to IBM, there are following three problems with Hyperledger Composer:
Composer has been designed from the start to support multiple blockchain platforms, not just Fabric - but this design has come at a cost. This design has meant that there are two completely different programming models - the Fabric programming model (chaincode) and the Composer programming model (business networks). This has caused significant confusion to users, with them needing to make a "choice" between the two programming models, with very few similarities between the two. In this particular case choice has been a bad thing, with many users opting not to use the "optional" part past the initial exploration or POC stage.
This design has also made it a lot harder for us to adopt and expose the latest Fabric features. For example, one of the questions we are constantly getting at the moment is "when can I use the Fabric v1.2 private data feature with Composer?". Whilst we've taken some steps (getNativeAPI) to assist with this problem, it is extremely difficult for us to keep up with and aligned with the latest features in Fabric when we are trying to maintain a design that keeps us blockchain platform independent. This has meant that users have understandably stopped using Composer and instead have reverted to developing with Fabric.
Finally, those of you that have used Composer will likely be fans of our simple, easy-to-use APIs (JavaScript and REST) for building applications that interact with a blockchain network. There is a lot of code behind the scenes to enable these APIs that doesn't really belong in Composer. What we have ended up doing is glossing over the underlying, low-level Fabric APIs instead of pushing improvements directly into these Fabric APIs. Today it takes ~50 lines of code to submit a transaction using the Fabric APIs, whilst in Composer it takes ~5 lines of code, and that's wrong - Composer's value should not come from just making Fabric easier to use.
Please read this for details.