Recently, someone asked me how virtual machines really work on blockchain, and I realized it’s one of those concepts that sounds complicated but is more accessible than it seems. So here’s my attempt to explain it.

Let’s start with the basics. A VM is essentially a computer that doesn’t exist physically. Imagine you can create a computer inside your computer without buying any additional hardware. Your host machine (your current laptop or PC) lends its memory, processing power, and storage so that this VM can run. It’s like having multiple computers running at the same time on the same device.

What makes this possible is software called a hypervisor. It divides the physical resources of your machine so that multiple VMs can use them at the same time. There are two main types: Type 1, which are installed directly on the hardware (common in data centers and cloud platforms), and Type 2, which run on your regular operating system (better for development and testing).

Now, why would someone want to use a VM? There are several practical reasons. You can try different operating systems without touching your main machine. If you need to open a suspicious file or test an unknown application, doing it in an isolated VM protects your main computer. It’s also useful for running older software that no longer works on modern systems, or for developers to test code in different environments without hassle.

But where things get really interesting is in blockchain. Here, VMs aren’t just isolated environments—they’re the engine that runs smart contracts across the entire network. The Ethereum Virtual Machine (EVM) is probably the most well-known. It allows developers to write contracts in Solidity, Vyper, or Yul and deploy them on Ethereum and other compatible networks. The key point is that it ensures every node on the network follows exactly the same rules when processing these contracts.

Not all blockchains use the same VM. Each network implements its own version depending on what it prioritizes. Some, like NEAR and Cosmos, chose WebAssembly (WASM)-based virtual machines, which support contracts in multiple programming languages. Sui uses MoveVM. And Solana has its own Solana Virtual Machine (SVM), designed specifically to process transactions in parallel and handle massive volumes of activity.

Where you really see the impact is when you interact with dApps. When you do a swap on Uniswap, your transactions are being managed by smart contracts running inside the EVM behind the scenes. If you mint an NFT, the VM is executing the code that maintains ownership records. In Layer 2 rollups, specialized transactions use virtual machines such as zkEVM to execute smart contracts while benefiting from zero-knowledge proofs.

But not everything is perfect. VMs have real limitations. First, there’s performance overhead: they add an extra layer between the hardware and the code, which can slow things down or consume more resources than running applications directly. Then there’s operational complexity: maintaining VMs on cloud infrastructure or blockchain networks requires constant configuration and specialized knowledge. And finally, there’s the issue of compatibility: a smart contract written for Ethereum would need to be rewritten to work on Solana or other incompatible blockchains.

In summary, virtual machines are fundamental both in traditional computing and in blockchain. They enable flexibility, security, and efficiency. Even if you’re not a developer, understanding how VMs work gives you a much better idea of what’s happening behind the scenes in the DeFi tools and platforms we use every day.