When working with Ethereum rollups, a set of Layer 2 technologies that bundle many transactions into a single batch before anchoring them to the Ethereum mainnet. Also known as rollup solutions, they let users enjoy fast, cheap transfers while keeping Ethereum’s security guarantees.
One of the biggest reasons developers turn to Layer 2 scaling, systems built on top of the base chain to increase throughput without sacrificing decentralisation. It reduces gas costs by moving most computation off‑chain, then posts a cryptographic proof or summary to the mainnet. Think of it as a high‑speed highway that periodically checks in with the main road to stay safe. This approach not only eases network congestion but also opens the door for richer dApps that were previously too expensive to run.
The two dominant families are Optimistic Rollup, which assumes transactions are valid and only runs fraud proofs if someone challenges them and zk‑Rollup, which generates a zero‑knowledge proof that mathematically guarantees correctness before posting data to L1. Optimistic rollups trade a few minutes of withdrawal delay for simpler implementation, while zk‑rollups sacrifice a bit of flexibility to achieve near‑instant finality and even lower fees.
In practice, an Optimistic Rollup like Arbitrum or Optimism presents a batch of transactions to Ethereum, then waits a 7‑day dispute window. If no fraud proof appears, the batch is considered final. This model works well for DeFi apps that can tolerate a short delay. By contrast, zk‑Rollups such as zkSync or StarkNet compute a SNARK or STARK proving all state transitions are correct, letting users exit in seconds. The proof itself adds a small computational overhead, but the gas saved on each transaction usually outweighs that cost.
Choosing the right rollup depends on your priorities. If you need the fastest withdrawal experience and want to minimise fees, zk‑Rollup is often the better fit. If you’re building a complex DeFi protocol and can handle a modest exit lag, Optimistic Rollup gives you more expressive smart‑contract capabilities. Both solutions require a bridge contract to move assets in and out, which means you’ll interact with a smart‑contract bridge that locks tokens on L1 and releases them on L2. Understanding the bridge’s security model is essential—many incidents stem from poorly audited bridge code.
Below you’ll find a curated set of articles that dig deeper into these concepts, from compliance considerations and exchange reviews to real‑world use cases. Whether you’re a developer looking to deploy on a rollup or a trader hunting lower fees, the posts ahead will give you the context and actionable insights you need to make the most of Ethereum’s scaling future.
Rollups bundle Ethereum transactions off‑chain, boosting throughput to thousands of TPS while slashing fees. Learn how optimistic and ZK rollups work, their trade‑offs, real‑world deployments, and the path to 100k TPS.