Offchain Labs Pushes Back on Vitalik Buterin’s RISC‑V Proposal, Says WASM Is the Smarter Path for Ethereum

In a move that could influence the next generation of blockchain architecture, Offchain Labs — the core developer behind the Arbitrum ecosystem — has publicly challenged Vitalik Buterin’s recently floated idea to adopt the RISC‑V instruction set architecture (ISA) as the foundation for Ethereum’s execution layer. The research team argues that while RISC‑V has become prominent in zero‑knowledge (ZK) proof systems, it may not be the optimal choice for smart‑contract delivery on layer one. Instead, they propose WebAssembly (WASM) as a more future‑proof format.

The Core of the Debate

Offchain Labs’ researchers introduce a useful conceptual separation: the “delivery ISA” (dISA), which defines how contracts are uploaded and stored on‑chain, versus the “proving ISA” (pISA), which is used by ZK‑VMs to verify execution. They argue that Vitalik’s proposal implicitly assumes a single ISA should serve both roles, but this assumption risks locking Ethereum into a format optimized for today’s ZK proving, not long‑term delivery and flexibility.

The team points out that RISC‑V has shown strong performance in ZK proof contexts, but it does not necessarily perform well in diverse node‑hardware environments, where most clients do not run native RISC‑V CPUs. Emulating RISC‑V on commonly used hardware introduces inefficiencies and may undermine decentralization. WASM, by contrast, executes efficiently on general hardware, is type‑safe, and benefits from a robust and well‑supported developer ecosystem.

Implications for Ethereum’s Future

The research suggests that anchoring Ethereum’s delivery ISA to RISC‑V now could effectively freeze the ecosystem into a proving‑ISA strategy that may become outdated as ZK‑VM architectures evolve. They caution that RISC‑V was never designed primarily for ZK proving or smart‑contract delivery but rather for hardware microprocessors — a fact that limits its long‑term suitability in a general‑purpose blockchain context.

By selecting WASM for contract delivery, with the option to compile it into whatever proving ISA emerges as superior, the blockchain ecosystem retains flexibility, avoids hardware lock‑in, and aligns smart‑contract deployment with a mature and widely supported programming standard. Offchain Labs argues WASM could philosophically serve as an “Internet protocol” layer for smart contracts — agnostic to the underlying hardware or proof system.

Why This Matters Right Now

Ethereum is nearing a set of protocol design decisions that will shape not just the next upgrade, but its evolution over the coming decade. As ZK proof technologies evolve and node hardware becomes increasingly heterogeneous, selecting an ISA for Layer 1 becomes a strategic architectural choice, not just a technical one. If Ethereum adopts an ISA optimized solely for today’s proving stack, it may compromise adaptability, decentralization, and inclusivity across hardware platforms.

Offchain Labs’ response reframes the ISA decision as a battle between flexibility and immediate efficiency. Their argument is simple: prioritize future‑proofing over optimization for today’s ZK tech.

What to Monitor

Over the next several months, developers and observers should keep an eye on Ethereum’s core roadmap and community discussions. Will the network choose separate ISAs for delivery and proving? Will it commit to RISC‑V or pivot to WASM? The maturity of tooling, compiler support, and infrastructure around WASM could prove decisive, especially as alternative ZK‑VM designs begin to experiment with non‑RISC architectures.

Ultimately, this may look like a low‑level implementation dispute, but it reveals something deeper: Ethereum’s infrastructure choices today will define its trajectory for the next decade. The RISC‑V vs. WASM debate is not just about smart contracts — it’s about what kind of computational future Ethereum wants to build.