Blockchain platforms are foundational infrastructures for building decentralized applications, smart contracts, and token economies. Examples include Ethereum, Solana, Binance Smart Chain, and Polkadot. These platforms vary in consensus mechanisms, scalability, transaction speed, and ecosystem support. They provide tools and environments for developers to create secure and transparent digital systems without centralized control. Blockchain platforms are critical in transforming industries like finance, healthcare, supply chain, and gaming, enabling peer-to-peer interactions, digital ownership, and new economic models.