A software program capable of operating a Lightning node and engaging with the Lightning Network on the backend. Each implementation follows the BOLT (Basis of Lightning Technology) specifications, ensuring compatibility and seamless interaction between nodes within the network.

Some popular Lightning Implementations include Core Lightning, LND (developed by Lightning Labs), and Eclair (developed by ACINQ). While they may have different features, programming languages, or optimizations, their adherence to the BOLT standards guarantees interoperability.