Ethereum, a smart contract Layer 1 blockchain, faces scalability limits despite its robust architecture. Layer 2 (L2) solutions such as Channels, Plasma, Rollups and Validiums aim to boost throughput by offloading execution while retaining Ethereum’s security. Rollups, the leading L2 approach, introduce new actors (Sequencer, Prover, Verifier) which raise decentralization concerns. To address this, a framework defining decentralization levels (0–2) has emerged, guiding L2s toward greater trustlessness. While most L2s remain centralized, the community is actively progressing toward scaling Ethereum in a decentralized way.