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.

L2 Rollups: Optimistic and ZK, Data Availability Intermediate Infrastructure • ~15–18 min read • Updated: 08/08/2025 TL;DR: Rollups execute off the base layer and post summaries back: Optimistic rollups rely on fraud proofs during a challenge window; ZK rollups post validity proofs the base layer can verify quickly. Security depends on where data lives: L1