Hyperledger Composer is a design tool for building smart contracts and business applications on the blockchain. It is designed for rapid prototyping of chaincode and asset data models for use with Hyperledger Fabric. As a Fabric-specific tool (so far), it is primarily designed around helping with Hyperledger Fabric specific concepts, such as assets, identity management, transactions, and the resultant chaincode used to power the business rules between all these items.

It is not designed as a "fire-and-forget" tool, where someone can build an entire ecosystem from scratch to production, rather it is designed for rapid visual prototyping to get testable applications up and running quickly, with finer details iterated directly in the codebase. IBM hosts a demo online at https://composer-playground.mybluemix.net/editor.

The primary users of Composer will be blockchain developers (especially new developers) and some technical business users. It sits well as part of an agile process for developing blockchain applications, allowing developers, network administrators, and technical business users to visualize the network and the code operating on it.