Cosmos
Cosmos is a decentralized network of independent, scalable, and interoperable blockchains, often referred to as the 'Internet of Blockchains'. It enables different blockchain networks to communicate and transact with each other through its Inter-Blockchain Communication (IBC) protocol. The platform uses a proof-of-stake consensus mechanism and provides tools like the Cosmos SDK for developers to build custom, application-specific blockchains.
Developers should learn Cosmos when building decentralized applications (dApps) that require interoperability between multiple blockchains, such as cross-chain DeFi protocols, NFT marketplaces, or supply chain solutions. It's particularly useful for projects needing high scalability and customizability, as the Cosmos SDK allows for tailored blockchain designs without relying on a single, monolithic chain like Ethereum.