Railgun vs Aztec Network: EVM Privacy SDK vs zk-Rollup

Deploy on any EVM chain: Uses smart contracts and zero-knowledge proofs to add privacy to existing L1/L2s like Ethereum, Polygon, and Arbitrum. This matters for protocols needing privacy features without migrating ecosystems. Lower barrier to adoption for dApps.

Privacy for any ERC-20 or NFT: The system is asset-agnostic. Supports private swaps, lending, and transfers via integrations with protocols like Uniswap and Balancer. This matters for users and builders who require privacy for a diverse portfolio without locking funds into a new chain.

Dedicated zk-rollup with private smart contracts: Offers fully private computation (private state) via its Noir programming language. This matters for applications requiring complex, private logic (e.g., private DeFi, confidential voting) that isn't possible with simple asset shielding.

Default privacy and account abstraction: User shields funds on deposit, and all subsequent interactions are private. Native batched proving reduces individual user cost. This matters for mass-market applications where user experience and strong privacy guarantees are paramount.

Relies on underlying chain's security and data availability. Privacy set and note decryption are off-chain, but the system's integrity depends on the public L1. This can be a consideration for applications requiring maximum censorship resistance at the base layer.

Requires bridging to a separate L2. Users and liquidity must migrate to the Aztec rollup, creating fragmentation. While efficient, it's a separate ecosystem with its own tooling (Noir, Aztec.js). This matters for projects deeply integrated into the general EVM toolchain.

Seamless SDK Integration: Deploy private transactions on any EVM chain (Ethereum, Polygon, BSC) without migrating assets. This matters for protocols needing privacy features like private DeFi vaults or shielded governance voting on existing infrastructure.

No Bridge Lock-up: Users retain asset custody in their existing wallets using zero-knowledge proofs. This matters for users and protocols who want privacy but cannot afford the capital inefficiency or security risks of bridging to a new L2.

Application-Level Privacy Only: Privacy is at the transaction level via the RAILGUN smart contract. Complex private smart contract logic (like a fully private AMM) is not natively supported. This matters for developers building novel, computation-heavy private dApps.

Potential Censorship Vector: Transactions require a relayer to pay gas, creating a trusted component. While decentralized relayers exist, it adds a layer. This matters for applications requiring maximum censorship resistance and permissionless guarantees.

Programmable Privacy with Noir: A dedicated L2 with a Turing-complete zk-SNARK VM (Aztec VM) and the Noir language. This matters for developers building complex, private applications like confidential DeFi or fully private identity systems from the ground up.

Private State & Batching: All transactions are private by default and batched into succinct proofs, offering strong network-level privacy and lower fees at scale. This matters for high-volume applications where both transaction data and chain state must be concealed.

Closed Environment: Requires bridging assets to the Aztec L2 rollup, isolating liquidity and composability from the broader EVM ecosystem. This matters for users and protocols who prioritize interoperability with mainnet DeFi like Uniswap or Aave.

New Stack & Tooling: Developers must learn the Aztec network, Aztec.nr framework, and Noir language, a steeper curve than using an SDK. This matters for teams with tight timelines or those wanting to quickly add privacy to an existing EVM dApp.

SDK-based integration: Deploys as a smart contract system on existing EVM chains (Ethereum, Polygon, Arbitrum). This enables seamless composability with DeFi protocols like Aave, Uniswap, and Curve directly from private balances. Ideal for teams prioritizing integration speed and leveraging existing ecosystem liquidity without a new chain.

Requires third-party relayers: Users need external parties to submit private transactions on-chain, creating a potential coordination point and adding a fee layer. While trustless, it adds complexity versus native L1 submission. This matters for architects designing for maximum censorship resistance.

Full-stack zk-rollup: Provides private computation and data availability on a dedicated L2. Enables complex private smart contracts (zkApps) with ~300 TPS for private payments. This architecture is superior for applications requiring complex private logic, not just asset transfers.

Separate rollup environment: While bridging exists, assets and applications are siloed from the broader EVM ecosystem. Interacting with mainnet DeFi requires a bridge hop, adding latency and cost. A significant consideration for protocols whose value depends on direct composability with Ethereum mainnet.