New Solidity compilers arrive with major speed gains for Ethereum developers

Ethereum developers just got two reasons to update their toolchains. Within days of each other in September 2026, the Nomic Foundation shipped slang-solx, a new LLVM-based Solidity compiler backend, and the core Solidity team released v0.8.37 with security fixes and fresh opcode support.

The bigger headline belongs to slang-solx. Launched on September 7, the compiler backend achieves speeds up to 5x faster than the traditional solc compiler when running in via-IR mode, and roughly 1.7x faster in legacy mode.

What slang-solx actually changes

Slang-solx attacks the problem at the backend level by leveraging LLVM, the same compiler infrastructure that powers Clang for C/C++ and Rust’s compiler.

The project traces back to a compiler effort called solx that Matter Labs initiated in 2025. At some point the work transitioned to the Nomic Foundation, the organization behind Hardhat, Ethereum’s most popular development framework.

Currently, slang-solx supports Solidity 0.8.34 and is explicitly positioned for development use rather than production. Nomic is not recommending it for mainnet deployments yet.

The 5x speed improvement in via-IR mode is particularly noteworthy because via-IR is the compilation pipeline the Solidity team has been pushing as the future-facing approach, replacing the older legacy pipeline.

Solidity v0.8.37 fills in the gaps

Three days after slang-solx landed, on September 10, the core Solidity team released version 0.8.37. The release includes two bug fixes rated at low to medium severity.

Version 0.8.37 also introduces support for the SLOTNUM opcode tied to the Amsterdam EVM version. SLOTNUM gives contracts access to slot number information, extending the EVM’s capabilities in line with Ethereum’s ongoing protocol upgrades.

The release fits into a steady cadence the Solidity team has maintained throughout 2026. Version 0.8.35 shipped in April, 0.8.36 arrived in July, and now 0.8.37 rounds out the summer.

Why faster compilers matter beyond developer convenience

The combination of slang-solx and Solidity v0.8.37 signals something about Ethereum’s broader tooling ecosystem: the core team handles language-level improvements and security patches while independent organizations like Nomic tackle performance and developer experience.

For protocols and teams building on Ethereum, slang-solx is worth evaluating for development environments now, with production use likely following once the compiler matures and undergoes more rigorous auditing. Solidity v0.8.37 should be adopted as part of normal update hygiene, particularly given the security patches.