Nodes, L1/L2, Rollups

Sidechains & State Channels Two non-rollup scaling approaches: separate chains with their own security, and off-chain micro-transactions with on-chain settlement. TL;DR: Sidechains: Independent consensus + bridge to L1. Cheaper, but inherit sidechain security (not L1). State channels: Lock funds on L1, exchange signed updates off-chain, settle final state on-chain. Great for rapid, repeated interactions. In

ZK Rollups: zkSync & StarkNet Validity proofs compress execution and prove correctness to Ethereum for fast finality and withdrawals. TL;DR: ZK rollups submit validity proofs so Ethereum can verify a batch is correct. Withdrawals are typically faster; tradeoffs include prover complexity/cost and EVM compatibility differences. In this lesson How ZK rollups work EVM-compatibility spectrum zkSync

Optimistic Rollups: Arbitrum & Optimism Scale Ethereum by executing off-chain and posting data on-chain, fraud proofs keep things honest. TL;DR: Optimistic rollups assume transactions are valid by default; anyone can challenge via fault/fraud proofs. Cheap & EVM-friendly, but withdrawals wait through a challenge window. In this lesson How optimistic rollups work Bridging & the challenge

Layer 1s: Ethereum vs Solana vs Avalanche Three popular base layers with different tradeoffs in security, performance, and developer experience. TL;DR: Ethereum (PoS, EVM-first): Deepest liquidity & ecosystem; scales via L2 rollups. Solana (PoH + PoS, parallel runtime): High throughput, single global state, fast finality. Avalanche (Snow consensus, subnets): Customizable app chains with fast finality.

Layer 2 Rollups Explained: Optimistic and ZK, Data Availability, Bridges, and Real World Risk Checks Rollups are Ethereum’s main scaling path, but most explanations stop at slogans. This guide goes deeper: how rollups actually post data, what “security inheritance” really means, why data availability is the foundation of safe exits, and how Optimistic and ZK