If you have reached this far, congratulations! You have built the core of your blockchain application and the smart contract that directly reads, and more importantly, manipulates, the ledger that is the System-of-Record for your network. But, you are not close to finishing yet. As you can imagine, the contract is a sensitive piece of code that must be protected from misuse or tampering.

To produce a robust and secure application that is safe to release to business users, you must wrap the smart contract with one or more layers of protection and engineer it as a service that clients can access remotely through appropriate safeguards. In addition, the various stakeholders that wish to share a ledger and a smart contract may have unique and specific business logic needs that only they, and not the others, need to implement over and above the contract. For this reason, one blockchain application running one smart contract may end up offering different views and capabilities to different stakeholders.

In this chapter, you will first learn how to build a complete blockchain application from the ground up using our trade application as a guide and example. Later, you will learn about the various considerations that go into designing this application for a scenario of your choice and how to integrate that application with existing systems and processes.

The topics that will be covered in this chapter are as follows:

• Building a complete application
• Integrating the application with existing systems and processes