Rust and Smart Contracts - Ultimate Guide | RustMeUp

Rust and Smart Contracts - Ultimate Guide

Smart Contracts are self-executing contracts with the terms of the agreement directly written into lines of code. They run on blockchain and eliminate the need for intermediaries in various processes related to finance, real estate, legal industry, etc. Looking to build Smart Contracts? Consider Rust. It's a game-changer. This guide will enlighten you about Rust and its synergy with Smart Contracts.

Why Rust for Smart Contracts?

Rust is a system programming language that aims to provide memory safety, concurrency, and high performance. It was rated the "most beloved language" in the Stack Overflow Developer Survey for the past four years for good reasons:

  • Efficiency & Speed: Rust offers low-level details that provide the ability to write high-performance code.

  • Robustness: The language significantly reduces software crashes and security vulnerabilities. It is known for its uncompromising reliability and strong guarantees of memory safety.

  • Easy to Maintain codebase: Rust has high-level constructs that make complex architectures easier to manage.

  • Interoperability: Rust can interoperate with C and can be linked to other languages. Thus, making it easier to integrate with existing codebases and libraries.

In the realm of Smart Contracts, these utilities align ideally. Smart Contracts require high assurance since they handle and store value. Safety, speed, and robustness – some of Rust’s core features, are thus imperative for the successful execution of smart contracts.

Developing Smart Contracts with Rust

Tools and Libraries

There are several tools, libraries, and frameworks available to assist in developing smart contracts in Rust. Here are some:

  • ink!: It's a Rust-based eDSL from Parity Technologies. ink! allows developers to write smart contracts for blockchains built on the Parity Substrate platform.

  • solang: Solang is a Solidity to wasm compiler, allowing Ethereum smart contracts to be written in Solidity while running inside a Substrate chain.

  • Cosmwasm: Libraries for building safe, efficient, Cosmos SDK module, wasm smart contracts, and a Rust toolkit for building Wasm smart contracts.

Meeting the Blockchain Environment’s Requirements

Rust, like other languages, needs to meet specific conditions to accommodate the requirements of a blockchain environment. Here are a few things to be considered:

  • Determinism: The language must be deterministic. The same input will always produce the same output.

  • Metering: For a language to be used in a blockchain environment, it needs to incorporate the ability to measure or 'meter' the computational resources an operation uses.

  • No Forced Upgrades: Since it's hard to force upgrades in a decentralized system, language stability is highly desirable. Rust's promise of backward compatibility ensures that this requirement is met.

Writing a Simple Contract in Rust

Firstly, let's install the required tools:

# Install ink CLI
cargo install cargo-contract
# Install binaryen
brew install binaryen
# Build needed binaries
cargo contract build

Creating a new ink! project:

cargo contract new flipper

Here's a simple contract that can either return true or false.

use ink_lang as ink;

#[ink::contract]
mod flipper {
    #[ink(storage)]
    pub struct Flipper {
        value: bool,
    }

    impl Flipper {
        #[ink(constructor)]
        pub fn new(init_value: bool) -> Self {
            Self {
                value: init_value,
            }
        }

        #[ink(message)]
        pub fn flip(&mut self) {
            self.value = !self.value;
        }

        #[ink(message)]
        pub fn get(&self) -> bool {
            self.value
        }
    }
}

To compile the contract:

cargo contract compile

FAQs

Q1: Why are smart contracts important?

Smart contracts help to automate transactions, enhance security, reduce the need for intermediaries, and provide transparency, thereby reducing paperwork and saving time and cost.

Q2: Are smart contracts in Rust efficient?

Absolutely. Rust brings forth efficiency and speed and combines it with safety and robustness – making it an ideal choice for Smart Contracts.

Q3: What is ink!

ink! is a Rust-based eDSL for writing smart contracts for blockchains built on the Substrate platform.

Q4: Can I use Rust for Ethereum Smart Contracts?

While Solidity is the primary language for Ethereum Smart Contracts, the Solang compiler allows developers to use Rust. Solang translates Solidity to WASM, allowing it to run on Substrate chains.


Harnessing Rust’s powerful features to create Smart Contracts can improve their performance, safety, and robustness. Despite certain challenges, the ecosystem of Rust and Smart Contracts is being continually enriched by tools, libraries, and frameworks, making Rust a strong contender in the landscape of blockchain development.