#explain-card A [[Layer 2]] (L2) network or solution operates on top of an existing [[Layer 1]] blockchain to improve its scalability and efficiency. The primary goal of Layer 2 solutions is to increase transaction throughput ([[Transactions per second|transactions per second]]) and reduce transaction fees without compromising the security or decentralization of the main underlying Layer 1 network. Layer 2 solutions achieve this by processing transactions off the main chain (off-chain), thereby alleviating congestion on the Layer 1. Periodically, these off-chain transactions are bundled and anchored back to the Layer 1 network, which ensures that they benefit from the security and finality of the [[Base|base]] layer. There are several types of Layer 2 scaling solutions, each with its own mechanisms and trade-offs. Some common approaches include: - [[Rollup|Rollups]] (e.g., Optimistic Rollups, ZK-Rollups) - State Channels - Sidechains - Plasma These solutions aim to address the scalability challenges faced by many Layer 1 blockchains, making decentralized applications more usable and cost-effective for a wider audience. By offloading transactional and computational load, Layer 2s enable blockchains to handle a much larger volume of activity. Examples of Layer 2 solutions, particularly for [[Ethereum]], include: - [[Arbitrum]] - [[Optimism]] - [[Polygon]] (which has various solutions, including a PoS sidechain and L2 technologies) - [[ZKSync]]