Substrate
Substrate is an open-source blockchain development framework created by Parity Technologies, designed for building custom blockchains. It provides modular components, such as consensus mechanisms, networking, and runtime logic, allowing developers to create highly customizable and interoperable blockchains without writing everything from scratch. It is the foundation for the Polkadot and Kusama networks, enabling parachain development.
Developers should learn Substrate when building custom, scalable blockchains that need to integrate with the Polkadot ecosystem or require specific governance, consensus, or economic models. It is ideal for projects needing high flexibility, such as decentralized applications (dApps), enterprise solutions, or interoperable networks, as it reduces development time and leverages shared security through Polkadot.