What is a rollup?
A rollup is a Layer 2 scaling solution that executes transactions off-chain (on a separate execution layer) but posts compressed transaction data and state commitments back to the Layer 1 chain (typically Ethereum) for security and data availability. Rollups inherit L1 security while delivering 10-100x throughput and 10-100x lower gas costs.
Two rollup families
- Optimistic rollups (Arbitrum, Optimism, Base): assume transactions are valid by default; allow a fraud-proof challenge window (~7 days) before withdrawals finalise. Mature ecosystem; longer withdrawal latency.
- ZK rollups (zkSync, Starknet, Polygon zkEVM, Linea, Scroll): use validity proofs (zero-knowledge proofs) to mathematically prove correctness of each batch. Faster finality, smaller calldata, but more compute-intensive.
EIP-4844 (Proto-Danksharding)
Ethereum’s March 2024 Dencun upgrade introduced blobs — a dedicated data availability layer for rollups that dramatically reduced L2 gas costs (often 90%+). Blobs are temporary (pruned after 18 days) but sufficient for L2 fraud/validity proof windows. This was the first concrete step toward full Danksharding.
Türkiye’de rollup adopsiyonu
Türk geliştiriciler ve DeFi kullanıcıları için L2’lere (Arbitrum, Base, Optimism) geçiş gas tasarrufu nedeniyle hızla artmıştır; Btcturk, Paribu ve Binance TR yerel CEX’leri çoğu büyük L2’yi yatırma/çekme ağı olarak destekler. CASP düzenlemesi (7518) L2 işlemlerini doğrudan kapsamaz ancak fiat-on/off-ramp ve KYC zincirini etkiler. Türk kurumsal blockchain projeleri (örn. e-Devlet entegrasyonu hayalleri) genelde permissioned ağ tercih eder, public L2 değil.
Do: compare bridge security models (canonical vs. third-party) before moving large funds; use canonical bridges for L1↔L2; understand sequencer centralisation risk.
Don’t: assume all L2s are equally secure — fraud-proof activation status, sequencer decentralisation, and data availability all vary.