Rust excels at raw performance and memory safety, making it ideal for high-throughput, security-critical infrastructure. Its zero-cost abstractions and fine-grained control over system resources enable bundlers to process user operations (UserOps) with minimal latency and deterministic gas estimation. For example, the Stackup bundler, built in Rust, leverages these traits to achieve sub-second inclusion times and robust handling of peak loads on networks like Arbitrum and Optimism.
LABS
Comparisons
Rust vs Solidity for Bundler Implementation Performance
A technical analysis for CTOs and architects comparing Rust-based bundler node implementations against Solidity-based verifier smart contracts for Account Abstraction infrastructure. We benchmark performance, cost, and architectural trade-offs.
Chainscore © 2026
introduction
THE ANALYSIS
Introduction: The Bundler Architecture Dilemma
Choosing a language for your ERC-4337 bundler is a foundational decision that impacts performance, security, and long-term maintenance.
Solidity takes a different approach by prioritizing developer familiarity and seamless Ethereum Virtual Machine (EVM) integration. This results in a trade-off: while potentially less performant than a native binary, a Solidity-based bundler can be more easily audited by existing Web3 security firms and integrated with standard tooling like Hardhat and Foundry. Projects like Etherspot's Skandha bundler demonstrate this, offering a modular design that benefits from the vast ecosystem of Solidity libraries and patterns.
The key trade-off: If your priority is maximizing throughput and minimizing operational risk in a competitive mempool, choose Rust. If you prioritize rapid development, leveraging existing team expertise, and deep compatibility with EVM-centric toolchains, choose Solidity. The decision ultimately hinges on whether you are optimizing for infrastructure-level performance or ecosystem integration velocity.
tldr-summary
Rust vs Solidity for Bundler Implementation
TL;DR: Key Differentiators at a Glance
A high-performance bundler is critical for user experience and profitability. The language choice dictates performance, security, and development velocity.
01
Choose Rust for Performance & Security
Zero-cost abstractions and memory safety: Rust's compile-time guarantees eliminate entire classes of bugs (e.g., null pointer dereferences, data races) common in C/C++. This is critical for high-value infrastructure handling billions in MEV and user funds. Benchmarks show Rust-based bundlers like Reth and Suave achieve 2-3x higher transaction processing throughput than equivalent Go/JS implementations, directly impacting profitability.
2-3x
Higher TPS
0
Runtime GC Pauses
02
Choose Solidity for EVM-Native Logic & Speed to Market
Native integration with smart contract ecosystems: Implementing core bundler logic (e.g., paymasters, aggregation rules) in Solidity allows for on-chain verifiability and seamless composability with existing DeFi primitives. This enables rapid prototyping and leveraging battle-tested libraries from OpenZeppelin and Solady. Teams familiar with Ethereum development can iterate faster, crucial for validators or L2 teams launching a minimum viable bundler.
1000s
Pre-audited Libraries
03
Avoid Rust for Prototyping & Broad Hiring
Steeper learning curve and smaller talent pool: Rust's strict ownership model increases initial development time. Finding senior Rust developers with blockchain experience is harder and more expensive than finding Solidity devs. For a proof-of-concept or a team building their first infrastructure component, the productivity tax can be prohibitive. The ecosystem for blockchain-specific crates is also less mature than Solidity's tooling (Foundry, Hardhat).
~30%
Longer Dev Cycles
04
Avoid Solidity for Core Engine & Max Efficiency
EVM overhead and gas cost for complex logic: Running the bundler's matching engine or complex validation in Solidity/EVM incurs significant computational and gas overhead. This reduces net profit per bundle and limits algorithmic complexity. For high-frequency, low-latency operations requiring direct hardware access (e.g., SGX for encrypted mempools), Solidity is not feasible. The performance ceiling is fundamentally lower.
10-100x
Higher Op Cost
HEAD-TO-HEAD COMPARISON
Rust vs Solidity for Bundler Implementation Performance
Direct comparison of execution performance, development, and ecosystem factors for bundler development.
| Metric / Feature | Rust | Solidity |
|---|---|---|
Execution Speed (Ops/sec) |
| ~300K (EVM) |
Gas Cost for Complex Logic | ~50K gas (optimized) | ~200K gas (standard) |
Memory Safety Guarantees | ||
Parallel Processing Support | ||
Primary Use Case | Core Bundler Logic & MEV | Smart Contract Wallets & Paymasters |
Ecosystem Maturity for Bundlers | High (e.g., Reth, Lighthouse) | Medium (e.g., Solidity reference) |
Learning Curve for Web3 Devs | Steep | Gentle |
pros-cons-a
PERFORMANCE & DEVELOPMENT TRADE-OFFS
Rust vs Solidity for Bundler Implementation
Choosing the language for your bundler node (e.g., for an ERC-4337 infrastructure) impacts execution speed, security, and team velocity. Here are the key technical differentiators.
01
Rust: Peak Execution Performance
Native compilation & memory safety: Rust compiles to machine code, enabling near-C++ speeds for mempool processing and signature verification. Its borrow checker prevents memory bugs, a critical advantage for high-value infrastructure handling user operations. This matters for high-throughput bundlers where latency (sub-100ms p95) directly impacts user experience and profitability.
~5-10x
Faster than Solidity/JS
Zero-cost
Abstractions
02
Rust: Ecosystem & Integration Hurdles
Younger EVM tooling: While libraries like ethers-rs and alloy are maturing, they lack the depth of JavaScript's ethers.js or viem. Direct interaction with smart contracts and debugging can be more complex. This matters for teams prioritizing rapid prototyping or those deeply integrated with the Node.js/TypeScript ecosystem (e.g., using Hardhat for testing).
< 50%
Of JS lib coverage
03
Solidity/JS: Native Smart Contract Synergy
Seamless ABI integration: Implementing a bundler in JavaScript/TypeScript (using ethers.js) allows for identical tooling and patterns as your smart contracts. Testing with Foundry or Hardhat is streamlined. This matters for full-stack teams where the same developers maintain both the protocol contracts and the bundler, reducing context switching.
100%
ABI compatibility
04
Solidity/JS: Runtime Performance Ceiling
Interpreted runtime overhead: Node.js/V8 execution is fundamentally slower for CPU-intensive tasks like cryptographic operations and batch transaction simulation. This creates a hard ceiling on TPS and increases hardware costs for scaling. This matters for production-grade bundlers competing in competitive mempools where marginal speed gains translate to significant MEV capture.
~100-200 ms
Added latency p95
pros-cons-b
Rust vs Solidity for Bundler Implementation Performance
Solidity Verifier Contract: Pros and Cons
Key strengths and trade-offs at a glance for CTOs and Architects choosing a language for high-performance, on-chain verifier logic.
01
Rust: Peak Execution Speed
Native performance and memory safety: Rust compiles to WebAssembly (WASM) or native binaries, enabling sub-10ms verification times for complex operations like BLS signature aggregation. This is critical for high-throughput bundlers (e.g., those processing 1000+ UserOperations/sec) where CPU is the bottleneck. Benchmarks in projects like Starknet's sequencer show Rust outperforming Solidity equivalents by 5-10x in pure computation.
5-10x
Faster Compute
< 10ms
Verification Time
02
Rust: Superior Tooling for Off-Chain Components
Rich ecosystem for system-level development: Libraries like Tokio for async runtime, RocksDB bindings for state management, and arkworks for advanced cryptography allow building robust, performant bundler nodes (e.g., Reth, Erigon). This matters for teams building full-stack infra where the verifier is part of a larger node service, ensuring consistency between off-chain validation and on-chain contracts.
03
Solidity: Native EVM Integration & Gas Optimization
Direct access to EVM opcodes and gas semantics: Solidity contracts can be finely tuned for gas efficiency, a non-negotiable for on-chain verification costs. Using Yul or inline assembly, expert developers can achieve gas costs 15-30% lower than naive implementations. This is paramount for protocols where verifier gas fees are passed to users (e.g., account abstraction bundles). Tools like Hardhat and Foundry provide precise gas profiling.
15-30%
Gas Savings Potential
04
Solidity: Ecosystem Uniformity & Security
Uniform audit surface and developer familiarity: The entire stack—verifier, factory, entry point—is in one language, reducing context-switching and audit scope. Security tools like Slither, MythX, and formal verification (e.g., Certora) are most mature for Solidity. This is decisive for protocols with >$100M TVL where a single bug is catastrophic. The Ethereum Foundation's canonical contracts are written in Solidity for this reason.
CHOOSE YOUR PRIORITY
Decision Framework: Choose Based on Your Use Case
Rust for Performance
Verdict: The clear choice for high-throughput, low-latency bundlers. Strengths: Native compilation to machine code yields sub-millisecond block processing and deterministic execution critical for MEV capture. Memory safety without a garbage collector prevents unpredictable pauses. Enables direct systems-level optimizations for cryptographic operations and state management. Example: Flashbots' SUAVE relay prototype leverages Rust for its high-performance order flow auction. Trade-offs: Steeper learning curve and longer development cycles can impact time-to-market.
Solidity for Performance
Verdict: Not applicable for core bundler logic; used for auxiliary smart contracts. Context: Solidity's performance is constrained by the EVM's gas model and interpreter overhead. It is unsuitable for implementing the bundler's core sequencing, validation, or mempool logic which require systems programming performance. Its role is limited to writing the Paymaster or Aggregator verification contracts that the bundler interacts with.
verdict
THE ANALYSIS
Final Verdict and Recommendation
Choosing between Rust and Solidity for a bundler is a foundational decision impacting performance, security, and team velocity.
Rust excels at raw execution performance and memory safety, making it ideal for the high-throughput, low-latency demands of a production bundler. Its zero-cost abstractions and fine-grained control over memory (e.g., avoiding garbage collection pauses) directly translate to higher transactions per second (TPS) and lower latency in operations like mempool management and batch submission. For example, the Rust-based succinct-rs library and bundlers like Sovereign SDK demonstrate sub-millisecond proof generation times, a critical metric for user operation inclusion speed.
Solidity takes a different approach by prioritizing ecosystem integration and developer familiarity within the EVM landscape. This results in a trade-off: while its execution is inherently constrained by the EVM's gas model and higher-level abstractions, it allows for seamless interoperability with core smart contracts and existing tooling like Hardhat and Foundry. A bundler's core logic written in Solidity can be more easily audited and composed with account abstraction standards like ERC-4337, but may struggle with the computationally intensive tasks of signature aggregation or proof verification that Rust handles natively.
The key trade-off: If your priority is maximizing throughput, minimizing latency, and building a performant, secure system from the ground up, choose Rust. This is the path for teams building infrastructure-first, like a new L2 sequencer or a high-frequency bundler service. If you prioritize rapid prototyping, deep EVM/Smart Contract Wallet integration, and leveraging a vast pool of existing Solidity talent, choose Solidity. This suits teams extending an existing EVM ecosystem or where the bundler logic is less computationally bound.
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