L2 Development Toolchain 2026 — A Generational Shift to op-reth and EIP-8130

The core of the 2026 Ethereum Layer 2 development environment is maximizing productivity and gas efficiency. Replacing heavy, legacy client forks and complex off-chain infrastructure, Rust-based execution engines and native account abstraction at the protocol layer have become the new development standard. In particular, the retirement of op-geth and the introduction of EIP-8130 are completely reshaping how rollup nodes are operated and transactions are architected. This post covers the background of this toolchain shift and examines the practical changes builders must immediately reflect in their architectures.

The End of op-geth and the Era of op-reth and kona-client

Following the Karst hard fork applied on July 8, 2026, support for op-geth (the Go-based client that long served as the standard in the OP Stack ecosystem) and op-program has been completely terminated. Although official technical support ended in late May 2026, any legacy clients will fail to sync with the main chain after this hard fork. Therefore, not only node operators but also builders running local test nodes must now fully transition to the high-performance Rust-based client, op-reth, and the Rust-based proof system, kona-client.

The reason for this change in the execution environment, beyond performance improvements, is the advancement of the fault proof system via the introduction of the new CANNON_KONA dispute game type. The most practical hurdle developers face when configuring local test or archive nodes is that the database format used by legacy op-geth is incompatible with op-reth. While op-geth uses LevelDB or Pebble, op-reth utilizes the high-speed MDBX format; existing data directories cannot be reused, requiring users to either re-download snapshots or sync completely from the genesis block.

The environment for running nodes via terminal has also been updated to follow the Rust package structure as shown below.

# 과거: Go 기반의 op-geth 실행 예시
op-geth \
  --datadir ./data \
  --rollup.sequencerhttp=https://mainnet-sequencer.optimism.io \
  --http

# 현재: Rust 기반의 op-reth 실행 예시 (최소 v2.3.3 버전 필요)
op-reth node \
  --chain optimism \
  --rollup.sequencer https://mainnet-sequencer.optimism.io \
  --http \
  --http.api eth,net,web3,debug,engine

To properly run the aforementioned op-reth node, you must complete the 1-on-1 communication setup with the consensus client, op-node, via JWT authentication. Additionally, with the addition of the L2 contract manager module for network upgrades, it is essential for local development environments to update Docker Compose configurations using op-reth images of at least v2.3.3, which include the new protocol rules.

EIP-8130 and EIP-8140 — The Advent of Native AA Without Bundlers

The complex off-chain infrastructure previously required for implementing smart contract accounts is finally being integrated into the blockchain execution engine. With the Cobalt upgrade scheduled for September 2026, Base is integrating EIP-8130 and EIP-8140 directly into the Reth V2 execution engine, ushering in the era of native account abstraction. This key change completely removes the reliance on off-chain bundlers and entry-point contracts—the chronic bottlenecks of the legacy ERC-4337 model.

[ERC-4337 흐름]
사용자 서명 -> [오프체인 번들러] -> [엔트리포인트 컨트랙트] -> [스마트 계정] -> 트랜잭션 실행
               (대체 메모풀 필요, 가스 시뮬레이션 오버헤드 발생)

[EIP-8130 (0x79) 흐름]
사용자 서명 -> [Reth V2 실행 엔진] (AccountConfiguration 시스템 컨트랙트로 즉시 검증) -> 트랜잭션 실행
               (번들러와 엔트리포인트 완전 우회, O(1) 속도로 처리)

EIP-8130 introduces a new native transaction type: 0x79. This method performs transaction verification directly within the execution engine rather than through smart contract calls in the EVM. Because signatures are verified at the virtual machine level without going through a bundler, transaction byte size is reduced by 83.4%, resolving the persistent user experience issues of gas fee calculation errors and transaction cancellations during network congestion.

Developers can already verify these performance improvements on the dedicated testnet, Base Vibenet. Benchmark results show that compared to legacy ERC-4337, standard USDC transfer gas fees have decreased by approximately 63.2% (from 125,000 to 46,000 gas), and passkey-based gas-subsidized transfers have decreased by 60.3% (from 173,000 to 68,700 gas). As verification computational costs have dropped to levels comparable to standard Externally Owned Accounts (EOAs), it is now possible to seamlessly design on-chain AI agent payment flows that operate at high speeds without the risk of gas limit prediction failures.

Smart Contract Development Expanding into WASM and zkVM

Attempts to overcome the computational speed and memory limitations of the EVM have been fully integrated into practical toolchains via multi-VM structures. Arbitrum Stylus has embedded a secondary virtual machine that executes WebAssembly (WASM) directly into the execution engine, putting it on par with the standard EVM. This allows builders to write high-performance smart contracts in Rust, compile them into WASM files, and deploy them on-chain. Thanks to WASM’s high computational efficiency, complex cryptographic operations are 10x to 100x cheaper than the EVM, with memory usage costs reduced by 100x to 500x. Math operation loops that were gas-intensive in the EVM—such as the Poseidon hash essential for zero-knowledge proofs—can now be optimized in Rust and processed with minimal gas in the 10,000-unit range. These high-performance contracts interact and exchange tokens with existing Solidity contracts without restrictions.

The ZK-rollup camp is also rapidly shifting toward general-purpose VM architectures to overcome the limitations of complex VM circuit design. Notably, Scroll has discarded its Halo2-based zkEVM circuits in favor of the openVM prover, a general-purpose RISC-V virtual machine, via the Euclid upgrade. Previously, developers were forced to follow complex processes to manually verify the circuit limits of transactions within specific gas limits; the transition to a general-purpose zkVM system now supports zero-knowledge proof generation without complexity constraints.

At the same time, the state storage structure has successfully reverted from the ZK-friendly zkTrie back to the Ethereum standard: the Merkle Patricia Trie (MPT). Thanks to openVM’s powerful proving performance, it has become possible to prove standard MPTs directly, significantly reducing the compatibility cost for external dApps dealing with L2 state proofs. When combined with optimizations for data availability overhead, sequencer bottlenecks have been entirely resolved, securing rapid 1-second block times. For builders, this means receiving powerful infrastructure that goes beyond simple compilation optimization: WASM for computational density and zkVM for removing verification limits.

Three Action Guidelines for L2 Builders in 2026

The 2026 Layer 2 ecosystem is evolving to reduce infrastructure complexity and push the performance of execution engines to their limits. The first step builders must immediately reflect in their practical architectures is transitioning their local development and testing environment execution clients to op-reth and kona-client to align with the Karst hard fork environment.

Next, you must strip away existing heavy, off-chain bundler dependencies based on ERC-4337 and prepare for a transition to next-generation SDKs that support the EIP-8130 0x79 transaction specification. Finally, in line with the multi-VM trend—including Stylus and openVM—it is important to accumulate smart contract design assets that leverage Rust to maximize computational efficiency rather than relying solely on Solidity.

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