Solidity vs Move for Implementing ERC-4337 Sender Contracts

Massive developer and tooling network: 4,000+ monthly active devs and battle-tested tools like Foundry, Hardhat, and OpenZeppelin. This matters for rapid prototyping and finding talent, as you can leverage existing ERC-4337 Bundler and Paymaster infrastructure from Stackup, Biconomy, and Alchemy.

Seamless compatibility with existing AA infrastructure: Native support for EntryPoint contracts and validation logic. This matters for deploying on major L2s (Arbitrum, Optimism, Base) where the AA stack is already EVM-native, minimizing integration friction and audit surface.

Resource-oriented programming prevents key vulnerabilities: Assets are non-copyable, non-droppable types enforced by the bytecode verifier. This matters for high-value account logic, as it eliminates reentrancy and accidental loss of funds by design, a critical advantage for smart accounts holding user assets.

Built-in prover (Move Prover) and parallel execution: Enables mathematical proof of contract invariants and leverages Aptos/Sui's parallel transaction processing. This matters for mission-critical financial logic requiring guaranteed correctness and for scaling AA operations with high throughput.

Your priority is time-to-market and ecosystem leverage. You're building on Ethereum L2s, need to integrate with existing AA service providers, and want to tap into the largest pool of Web3 developers and auditors.

Your priority is security-by-design and maximal performance. You're building a novel, high-throughput AA system on Aptos or Sui, handling complex asset logic, and can invest in a smaller but growing developer pool for long-term robustness.

Massive developer adoption: 4,000+ active GitHub repos and battle-tested tools like Hardhat, Foundry, and OpenZeppelin. This matters for teams needing rapid development, extensive libraries (e.g., Solady, Account Abstraction Kits), and immediate access to auditors familiar with EVM patterns.

Native ERC-4337 compatibility: The standard and core infrastructure (Bundlers, Paymasters) are built for the EVM. This matters for projects deploying on Ethereum L2s (Arbitrum, Optimism, Base) or needing to integrate with dominant wallets (Safe, Rainbow) and existing DeFi protocols (Uniswap, Aave).

Resource-oriented model: Assets are non-copyable, non-droppable types, preventing double-spend and accidental loss by default. This matters for high-value account contracts where wallet logic must be mathematically verifiable, reducing audit surface for custom signature schemes and asset custody.

Deterministic execution & on-chain proofs: Move's bytecode is verifiable, enabling formal verification tools like the Move Prover. This matters for protocols requiring maximal uptime guarantees and predictable gas costs, crucial for scalable social recovery or batch transaction logic in sender contracts.

Proven in production: Billions in TVL secured across 5+ years, but carries legacy risks like reentrancy and overflow bugs. This matters for teams who prioritize a well-understood risk profile and can leverage extensive testing suites and security patterns over novel language guarantees.

Limited ERC-4337 toolchain: Emerging bundler/paymaster support on Aptos/Sui and smaller developer pool (~10x fewer devs than Solidity). This matters for projects that cannot afford to build core infrastructure from scratch or require deep integration with the broader Ethereum ecosystem.

Dominant network effect: Over 90% of ERC-4337 infrastructure (Bundlers, Paymasters, Indexers) is built for Solidity. This ensures immediate compatibility with core AA services like Stackup, Alchemy, and Biconomy. Critical for teams prioritizing time-to-market and leveraging existing audits.

Battle-tested security: Reference implementations like the official EntryPoint and sample accounts (SimpleAccount) have undergone extensive security reviews. The prevalence of established patterns (e.g., multi-sig, session keys) reduces novel attack surfaces, a key consideration for protocols managing high-value assets.

Resource-oriented safety: Move's type system enforces strict ownership and prevents double-spending at the VM level. Custom assets are native resource types, eliminating common Solidity vulnerabilities like reentrancy for asset logic. Essential for novel financial primitives within AA accounts.

Designed for proofs: Move Prover and languages like Move allow for native formal specification. This enables mathematical verification of critical AA invariants (e.g., nonce monotonicity, signature validity) directly in the contract code, a decisive advantage for institutions requiring the highest assurance levels.

Higher verification overhead: Complex signature aggregations (e.g., BLS) or stateful validation logic can lead to high gas costs in the validateUserOp function. This directly impacts end-user experience and Paymaster sponsorship viability, a major constraint for mass adoption.

Limited AA Infrastructure: While Aptos and Sui support AA concepts, dedicated bundler networks, paymaster services, and indexers are nascent. Teams must build supporting infrastructure in-house, adding significant development overhead compared to the plug-and-play EVM stack.