Layer 2s can make blockchain networks cheaper, faster, and therefore more useful for more people. Blockchain systems offer great technological benefits for money transfers and record-keeping in general; the main properties most often considered are decentralisation, trust– and permissionlessness, censorship resistance and immutability. These desired properties of decentralised networks come at the cost of limited throughput, however. Even the most prominent networks of today, Bitcoin and Ethereum are only able to handle a fairly limited amount of transactions in a given time period; an average BTC transfer takes about 10 minutes, and some interactions with Ethereum dApps can cost hundreds of dollars in gas fees during congested. times. Scaling solutions to blockchains are an advanced topic with much ongoing research and development. The technical descriptions and differences between each is beyond the scope of this explainer, but they are well worth researching for the curious. For Bitcoin, the most notable L2 solution is Lightning Network. Ethereum has numerous Layer 2 implementations, with the two main approaches being Optimistic Rollups and Zero-Knowledge Rollups.