Ethereum Appchains vs Rollups: State Scope

Ethereum Appchains (e.g., Polygon Supernets, Avalanche Subnets) excel at state sovereignty. They maintain their own independent state and consensus, enabling radical customization of the virtual machine, fee token, and governance. For example, dYdX migrated to a Cosmos-based appchain to implement a custom order book and capture 100% of its transaction fees, a model impossible on a shared rollup. This sovereignty allows for peak performance, with chains like dYdX V4 achieving over 2,000 TPS for its specific use case.

Rollups (e.g., Arbitrum Orbit, OP Stack, zkSync Hyperchains) take a different approach by inheriting security from Ethereum while managing execution off-chain. This results in a critical trade-off: they sacrifice full state sovereignty for stronger security guarantees and native interoperability within their ecosystem. An Optimism Superchain rollup shares a bridging standard and security model with other OP Chains, but its state rules and upgrade keys are ultimately constrained by the shared settlement layer on Ethereum L1.

The key trade-off: If your priority is maximum control, custom economics, and isolated performance for a specific application, choose an Appchain. If you prioritize leveraging Ethereum's security, seamless composability with major DeFi protocols, and a proven migration path, choose a Rollup. Your choice defines who controls your chain's destiny.

Ethereum Appchains (e.g., built with Polygon Supernets, Avalanche Subnets, or Cosmos SDK) excel at providing unmatched sovereignty and performance isolation. By controlling their own validator set and consensus, they can achieve thousands of TPS with sub-second finality and near-zero fees, as seen with dYdX's v4 chain. This model is ideal for applications like high-frequency gaming or proprietary financial products that require custom gas tokens, governance, and upgrade paths without external constraints.

Rollups (e.g., Arbitrum, Optimism, zkSync Era) take a different approach by inheriting Ethereum's security and composability. They batch transactions on L2 and post proofs or data back to Ethereum L1, achieving ~2,000-10,000 TPS while remaining trust-minimized. This results in a trade-off: you gain deep liquidity and seamless interoperability with the mainnet ecosystem (e.g., Uniswap, Aave) but must operate within the rollup's virtual machine constraints and share block space with other apps, which can lead to fee volatility during congestion.

The key trade-off is sovereignty versus security composability. If your priority is customizability, predictable performance, and total control over the stack—and you can bootstrap your own validator network and liquidity—choose an Appchain. If you prioritize leveraging Ethereum's battle-tested security, existing user bases, and native access to a $50B+ DeFi TVL from day one, choose a Rollup. For most mainstream DeFi and consumer dApps where network effects are critical, a rollup is the pragmatic choice, while appchains serve specialized, high-throughput enterprises willing to manage their own chain infrastructure.