What is Heimdall Node?

A Heimdall node is a validator node that is integrated with Polygon's staking contract system on Ethereum to enable Polygon's Proof-of-Stake (PoS) consensus mechanism. This capability was realized by building on top of the Tendermint consensus engine with modifications to the signature scheme and specific data structures. Heimdall nodes oversee block validation, block producer committee selection, and checkpointing of Polygon's sidechain blocks to the Ethereum network. The Heimdall layer aggregates blocks produced by Bor nodes into a Merkle tree and publishes the Merkle root sequentially to the Polygon root chain (one of the Polygon sidechains).