Light Node

A light node is a node that participates in a blockchain network and can verify specific transactions or account balances without downloading and storing the network's entire transaction history, unlike a full node (see Kaavon's "Full Node" glossary definition). Instead, a light node typically relies on cryptographic proofs — such as a Merkle proof (see Kaavon's "Merkle Proof" glossary definition) — provided by full nodes it connects to, letting it verify a specific piece of data is genuinely part of the blockchain without needing the entire dataset itself.

This makes a light node practical to run on resource-constrained devices like mobile phones, where downloading and storing an entire blockchain's history would be impractical, at the cost of some additional trust placed in whichever full nodes the light node connects to for the data it doesn't independently verify. A light client (see Kaavon's "Light Client" glossary definition) is a closely related concept, often used somewhat interchangeably with light node, sometimes specifically emphasizing additional cryptographic techniques like sync committees that further reduce the trust a light node needs to place in its connected full nodes.