If you're trying to understand how validators work in the Sui blockchain, you’ll need to look at how they help maintain the network’s integrity and performance. Validators are responsible for processing transactions, reaching consensus, and securing the blockchain. In Sui, they play a unique role because of the network’s hybrid execution model. When transactions involve shared objects—like assets used by multiple users—validators use Byzantine Fault Tolerant (BFT) consensus to agree on the outcome. But when transactions involve only owned objects, they can be finalized instantly without full consensus. This setup allows you to enjoy both speed and security depending on the type of transaction.

To become a validator, you need to run a node and stake SUI tokens. The more tokens you stake, the more weight your validator has in the consensus process. You also earn rewards based on your performance and reliability. If you’re building an app or running a service on Sui, understanding how validators work helps you design systems that interact efficiently with the network.

One challenge you might face is deciding whether your app should use shared or owned objects. Shared objects require consensus and are slower to process, but they’re useful when multiple users need access to the same data—like in a multiplayer game or a decentralized exchange. Owned objects are faster and ideal for personal assets like wallets, profiles, or collectibles. By designing your app to minimize shared object usage, you can improve performance and reduce costs.

Here’s a simple example of how you might define a shared counter object in Move:

module example::SharedCounter {
    struct Counter has key {
        id: UID,
        value: u64,
    }

    public fun create(): Counter {
        Counter { id: UID::new(), value: 0 }
    }

    public fun increment(counter: &mut Counter) {
        counter.value = counter.value + 1;
    }

    public fun get_value(counter: &Counter): u64 {
        counter.value
    }
}

This counter can be shared across users, but every update will require consensus. If you redesign it to use owned counters, each user can manage their own without waiting for network agreement.

Validators also help manage gas fees and transaction prioritization. When you submit a transaction, you include a gas payment, and validators choose which transactions to process based on these bids. This system keeps fees predictable and ensures that high-priority transactions are handled quickly.