Interoperability is a characteristic of a product or system, whose interfaces are completely understood, to work with other products or systems, at present or in future, without any restrictions. Interoperability is essentially the ability to see and access information across various blockchain systems.

The ability of different decentralized networks to communicate with one another without any intermediaries will go a long way in giving rise to fully decentralized systems.

World Economic Forum has identified three main categories of interoperability methods as on 2021: Cross Authentication, Oracles and API gateway. Currently, Blockchains are not interoperable and one can operate on only one Blockchain at a time.

Eg: Either Bitcoin or Ethereum. Blockchain interoperability projects like Polkadot Blockchain and Cosmos Blockchain are working hard to change this and make various Blockchains interoperable.