Part 5: What are Validator Nodes?

What are Validator Nodes

Validator nodes are online servers running a blockchain’s client software. They all keep a copy of the ledger and are constantly talking to each other to make sure the copies are consistent as new data is added.

Validator node network
A network of validator nodes, each one with an identical copy of the ledger.

The fact that the ledger is not under control of a single entity but distributed among a network of independent validators is what makes blockchains:

Validators agree on the state of the ledger using a consensus algorithm that varies for each blockchain. While the implementation of the groundbreaking FCP protocol is being completed, Flare is currently using a variant of Avalanche‘s Snowman++ algorithm.

In Avalanche’s Snowman++, each round a validator is randomly selected to act as the leader and propose new blocks to be added to the ledger, which are then validated by the rest of nodes. To provide Sybil resistance, the probability of a node’s being elected the leader is proportional to the node’s stake, so this is effectively a Proof-of-Stake consensus. The shortcomings of Proof-of-stake are well known and include risk of centralization and the rich-get-richer effect, for example.

To compensate for this, Flare’s version of Snowman++ reduces the importance of a node’s stake and introduces a meritocratic factor: All Flare validators are also FTSO Data Providers, so their performance in this role has an impact on their chance to become round leaders.