The distinctions between Fabric, Cello, Composer, Explorer, and Caliper can be described as follows:

• Fabric is the application itself, and where the business logic will finally reside
• Composer is a tool to help build this logic and the final chaincode

Both Fabric and Composer are going to be principally involved in the development phase of a blockchain project, followed shortly after by Caliper for performance testing:

• Cello and Explorer are tools dealing more with the operations side of a project. Cello is used by DevOps teams to deploy and extend blockchain applications across servers and virtual machines
• Explorer is a monitoring tool to inspect what is going on across different ledgers

Finally, Hyperledger Quilt can be used to connect different ledgers and blockchains together. For instance, Quilt could be used to communicate from a Fabric-based system to the public Ethereum network, or to the ACH banking system, or all of the above.

Thus, the Hyperledger project has tools for end-to-end creation, operation, and interoperability of blockchain-based application ecosystems.