Solidity and Rust are the two main programming languages used by web3 developers to build web3 applications on Ethereum Virtual Machine compatible blockchains and Solana respectively. Ethereum and Solana are two of the leading public smart contract-based blockchains in the world.

In this article, we’ll be talking about these two web3 programming languages and get to know why they are used by these powerful blockchains.

What is Solidity?

Solidity is an object-oriented, high-level, statically-typed programming language for implementing smart contracts on Ethereum, and it was created by a team of developers at Ethereum led by Christian Reitwiessner.

Here is an explanation of the terminology:

• Object-oriented - a programming approach that focuses on software development around data and objects instead of logic and functions
• High-level - languages that make software development more user-friendly by being independent of the computer hardware architecture
• Statically-typed - languages that check for errors and types during compile time

Solidity is designed to run on the Ethereum Virtual Machine (EVM), which is a runtime environment that works like a virtual computer to run software programs. The "programs" that the EVM runs are called smart contracts, and smart contracts are written in Solidity.

Blockchains that Support Solidity

Besides Ethereum, here are additional blockchains that support Solidity:

• Polygon - an Ethereum sidechain, Polygon allows developers to build scalable decentralized apps with low transaction fees
• Arbitrum - a layer 2 scaling solution that aims to reduce transaction fees and transaction congestion by moving computation off the Ethereum mainnet
• Optimism - an EVM-compatible layer 2 blockchain that uses optimistic rollups to reduce transaction fees and network congestion
• Polkadot - an interoperable and public blockchain, Polkadot makes use of its parachains to allow different blockchains (e.g. Astar) to interact with one another
• Avalanche - Avalanche is Proof-of-Stake blockchain that aims to address the blockchain trilemma.
• Celestial - Celestial is a data availability blockchain for Ethereum that orders and publishes transactions but does not handle computation. 
• Fuel - a modular blockchain that separates execution from data availability and consensus to create flexible throughput and maximum security

What is Rust?

Rust is a low-level, multiparadigm programming language with a focus on type safety and performance that enables developers to build fast and robust applications.

Let’s get more detailed.

• Low-level - Rust has a similar architecture to that of a computer’s processor, which makes it easier to write machine-efficient, high performance code
• Multiparadigm - languages are of different types (e.g. functional, dynamic, procedural, etc.), and multiparadigm languages have more than one type

Rust and Solana

Solana is an open-source programmable blockchain, which means that like Ethereum it supports the smart contracts (programs) functionality, and is often regarded as the world’s fastest public blockchain, with a block time of 400 milliseconds and the ability to handle 50,000 transactions per second. 

Solana permits development with C and C++ but uses Rust as its core programming language. Unlike Solidity, Rust was not created specifically for Solana, Rust has been in existence for years before Solana. However, it was chosen as a core programming language because of its high performance features.

To start building on Solana with Rust, developers only need to find a Solana RPC provider.

Blockchains that Support Rust

Besides Solana, here are additional blockchains that support Rust or a programming language based on Rust:

• Near - Near is a layer one proof of stake based blockchain and it uses sharding to solve the scalability problem.
• Aptos - Aptos is a layer one blockchain that is based on move, a programming language based on rust to implement smart contracts.
• Sui - Sui is the first implementation of a permissionless blockchain and it runs smart contracts written in move.

Solidity vs. Rust

Now that we’ve established what these languages are, we would compare and contrast them in this section.

What are the similarities between Solidity and Rust?

The main similarities shared by Solidity and Rust are their mutlichain compatibility and Turing completeness.

1. Multichain Compatibility

Although Solidity was designed specifically for Ethereum, it also supports layer two blockchains, sidechains, modular blockchains, and EVM-compatible layer one blockchains like Polkadot and Avalanche.

Similarly, Rust supports a variety of blockchains, including Near and Solana, and it is the programming language that inspired the Move and Sui languages. There is also a Rust implementation using Polkadot's substrate framework.

2. Turing Completeness

Both Rust and Solidity are Turing complete languages. A Turing complete language is any language that can solve any computational problem irrespective of its complexity. This is a feature that programming languages inherited from the Turing machine created by Alan Turing.

What are the differences between Solidity and Rust?

The two main differences between Solidity and Rust, besides the blockchains that support each programming language, is that Solidity is a high-level, object-oriented language and Rust is a low-level, multiparadigm language.

1. High-level vs. Low-level

Solidity is a high-level language that offers a high level of abstraction from the computer system architecture. Because of this, Solidity is simpler to learn and use, which makes it a more user-oriented language. In contrast, Rust is a low-level language that is closer to the computer's hardware and offers good memory efficiency and speed, making it a more machine-oriented language.

2. Object-oriented vs Multiparadigm

A programming paradigm is the approach or style used when solving a given problem. Solidity is an object-oriented language because it uses the object-oriented paradigm to solve problems.

Contrarily, Rust is a multiparadigm language, which means, it permits the use of different paradigms to solve problems. Some of the paradigms it supports are object-oriented, functional, and imperative among others. 

What are the benefits of building dapps with Rust rather than Solidity?

The two main benefits of building web3 dapps with Rust instead of Solidity are: Rust’s memory safety properties and fast speeds makes developing safer for engineers and apps more performant for customers. 

1. Memory safety

Memory safety is a property in some programming languages that prevent programmers from making certain types of memory-related errors. Rust achieves memory safety using the principle of ownership and borrowing.

Rust ensures memory safety by eliminating memory-related bugs during compile time, this makes it memory efficient without the use of a garbage collector like other memory-safe languages.

2. Speed and high output

Rust has the ability to create decentralized programs with high output and performance, which is a feature that is essential for dapps at scale. Rust performs more efficiently because it can achieve memory safety without using a garbage collector.

What are the tradeoffs of building web3 apps with Rust instead of Solidity?

The two main tradeoffs of building web3 applications with Rust vs. Solidity are: Rust’s compiler is slower compared to Solidity and Rust is generally more difficult to learn.

1. Slow Compiling

The Rust compiler is slow. Rust uses the low-level virtual machine (LLVM) to generate code, which occupies a major part of the Rust codebase and takes a non-trivial amount of time when regenerating machine code during compilation. Sometimes program compilation for large projects takes over 10 minutes.

2. Harder to Learn

Rust is challenging to learn for many reasons, one of which is that it is different. Being acquainted with its unusual ownership and borrowing system can be intimidating. Additionally, unlike some other languages, Rust programs are difficult to copy and paste, you are required to create your entire codebase from scratch.

What are the benefits of building dapps with Solidity versus Rust?

The two main benefits of building decentralized applications with Solidity over Rust are: Solidity is easier to learn, and there are a lot more developer tools for Solidity.

1. Easier to Learn

Solidity is a high-level language, which makes its code human-readable and understandable and it also has a syntax similar to that of Javascript, developers with previous experience writing Javascript, won’t find it difficult to learn solidity.

2. Lots of Developer Tools

Solidity has a ton of excellent developer tools available, it is supported by platforms like OpenZeppelin, which provides open-source libraries for secure smart contract development.

Solidity also has a couple of development environments (IDEs) like the Remix online IDE and Hardhat, a local developer environment. These IDEs provide tools and features that allow for the development of decentralized applications with ease.

What are the tradeoffs of building web3 apps with Solidity over Rust?

The two main tradeoffs of building web3 applications with Solidity vs. Rust are: Solidity’s integer overflows and static analysis make building difficult for developers.

1. Integer Overflow and Underflows

An integer overflow or underflow occurs when a number exceeds the amount that can be stored in a data type (its byte size). For example, ( 0 - 1 ) should give you ( -1 ), but it throws an error instead. This usually occurs in the previous versions of Solidity, versions prior to the solidity 0.8.

2. Difficult to Perform Static Analysis

Static analysis is the process of analyzing and troubleshooting code without actually running it. This type of debugging is challenging due to the Turing complete feature in solidity because there are numerous potential outcomes for the code.

Should I develop with Solidity or Rust?

Both Rust and Solidity are designed to support the building of smart contracts and scalable dapps. Therefore, the answer to this question comes down to your preferences and the blockchain ecosystem you want to build in.