How does a client app communicate with Hyperledger fabric chaincode (Smart Contracts)?

The app uses an SDK which invokes functionality on the chaincode which then announces the transaction to any peers required to endorse the transaction

The app uses Hyperledger Composer to communicate with CouchDB which in turn invokes chaincode functionality

Client apps don’t communicate with Hyperledger fabric directly, they must use Hyperledger Composer for the transmission

The app points to a node’s IP address, then calls an invoke function on the chaincode address to start the write process