What Is A Lightweight Wallet?
Cryptocurrency client software can either run a full node or a lightweight wallet. A full node will download and maintain a complete copy of the blockchain, whereas a lightweight wallet will not need to do this.
Because it doesn’t need to store or maintain the whole blockchain, a lightweight wallet uses less hard disk space and less bandwidth compared to a full node.
How Does a Lightweight Wallet Work?
Lightweight wallets use a simplified payment verification (SPV) mode which only requires them to download part of the blockchain. They will connect to full node clients and use bloom filters to ensure that they only receive transactions which are necessary and relevant to their operation.