What Is a “Finality Gadget” and How Does It Differ from Checkpointing?

A finality gadget is a mechanism that is used to provide absolute finality to a blockchain's blocks, meaning that they cannot be reverted. It differs from checkpointing in that it is an integral part of the blockchain's consensus mechanism, rather than a separate process that is anchored to another chain.

A finality gadget typically involves a supermajority of validators signing off on a block, which provides a much stronger guarantee of finality than a checkpoint. However, finality gadgets can be more complex to implement and can introduce additional overhead to the consensus process.