adding-precompiles

You can expose Substrate pallet functionality to Solidity smart contracts by implementing precompiles that bridge the EVM to your runtime, allowing direct access without crossing runtime boundaries. This requires creating a dedicated precompile crate and registering it in the runtime.

To create a custom precompile in a Moonbeam-style runtime, you implement the precompile interface using a provided macro, define a unique precompile address, set up a mock runtime for testing, and register the precompile within the runtime configuration.

Precompiles act as a bridge for Substrate and EVM interoperability by mapping specific runtime pallet features to predefined EVM addresses, enabling Solidity contracts to securely invoke native Substrate logic without adding heavy computational overhead to the EVM.

Yes, you need Rust to write EVM precompiles for Substrate because the underlying runtime and pallet logic are written in Rust, and the precompile interface must be implemented as a Rust crate that integrates directly with the Substrate runtime environment.

The best way to test a Substrate precompile before runtime registration is to set up a mock runtime environment alongside your precompile crate, allowing you to verify the interface logic and macro implementation against simulated pallet calls prior to deployment.

Precompiles are used instead of standard smart contracts for Substrate pallet access because they execute native Rust runtime code directly, avoiding the gas-heavy EVM interpretation overhead and enabling seamless, secure bridging between Solidity contracts and Substrate features.