🤔 What is Arbitrum Stylus? Arbitrum Stylus is a new programming environment on Arbitrum that allows developers to write smart contracts in Rust, C, and C++ — languages that compile to WebAssembly (WASM). This means:

⚡ 10x faster execution than EVM bytecode 🦀 Memory-safe contracts thanks to Rust's ownership model 💰 Lower gas costs due to WASM efficiency 🔗 100% EVM compatible — Stylus contracts can call Solidity contracts and vice versa

🛠️ What I Built: A Vault Contract During the camp, I built a Vault contract using the Stylus SDK in Rust. Here's a breakdown of the key components: Setting Up the Project rust#![cfg_attr(not(feature = "export-abi"), no_main, no_std)] extern crate alloc;

#[global_allocator] static ALLOC: wee_alloc::WeeAlloc = wee_alloc::WeeAlloc::INIT; This sets up a no-std Rust environment optimized for WASM compilation.

Defining Storage with sol_storage! rustsol_storage! { #[entrypoint] struct Vault { address asset; uint totalSupply; #[borrow] Erc20 erc20; } } The sol_storage! macro maps Rust structs directly to Solidity-compatible storage slots — no manual slot management needed!

Inheriting ERC20 rust#[public] #[inherit(Erc20)] impl Vault { // functions here } The #[inherit] attribute automatically re-exports all ERC20 functions through the Vault contract — similar to Solidity inheritance but cleaner.

Writing the Deposit Function rust#[payable] pub fn deposit(&mut self, amount: U256) -> Result<(), Vec> { let selector = function_selector!("transferFrom(address,address,uint256)"); let data = [ &selector[..], &msg::sender().into_array(), &contract::address().into_array(), // amount bytes... ]; } This uses raw calldata construction to call transferFrom on the underlying ERC20 asset — a powerful pattern for cross-contract interaction in Stylus.

💡 Key Takeaways ConceptWhat I Learnedsol_storage!Maps Rust structs to on-chain storage#[entrypoint]Marks the main contract struct#[public]Exports functions as external ABI#[inherit]Enables contract inheritance#[payable]Allows native token receptionfunction_selector!Builds raw calldata for cross-contract callsResult<(), Vec>Stylus error handling pattern

🏆 Why Arbitrum Stylus is a Game Changer

For Rust developers — you can now enter Web3 without learning Solidity For performance-critical apps — DeFi, gaming, and compute-heavy contracts benefit enormously For security — Rust's compiler catches memory bugs before deployment For gas optimization — WASM execution is significantly cheaper than EVM

🙏 Acknowledgements Huge thanks to HackQuest India for organizing Co-learning Camp 19. The structured learning path made Arbitrum Stylus approachable even for someone new to blockchain development. I'm now a Certified Arbitrum Builder and excited to keep building! 🎉

📌 Resources

Arbitrum Stylus Docs HackQuest Stylus SDK GitHub

Written by Arpit Bhardwaj | HackQuest India Co-learning Camp 19