Understanding blockchain interoperability

Interoperable blockchains are blockchains that can talk to each other. Each blockchain can read the other's state. There will be many occasions when you will want to enable your smart contracts to talk to centralized or other decentralized apps. When we talk about interoperability between DApps we're talking about something different than interoperability between blockchains.

Note

Enabling an Ethereum smart contract to check whether a file exists in IPFS or not is enabling interoperability between DApps, whereas enabling an Ethereum smart contract to fetch a Bitcoin account balance is enabling interoperability between blockchains.

Getting Ethereum smart contracts to make REST APIs call to centralized apps is considered enabling interoperability between Ethereum and WWW. But in this chapter, we will learn about interoperability between blockchains, specifically interoperability between Quorum networks.

There are various popular projects being developed...