Developed and delivered external self-pay invoice recognition for the getAlby/hub repository, focusing on backend development using Go and Lightning Network protocols. The feature enables automatic detection and handling of invoices generated outside LND by matching incoming transactions with identical payment hashes, streamlining cross-system invoicing and reducing the need for manual reconciliation. Updated and expanded test coverage to address multiple edge cases, ensuring robust and reliable operation across varied scenarios. Integrated the new process with existing LND-based flows to maintain operational consistency, ultimately improving cash-flow visibility and supporting seamless settlements for users managing invoices across different systems and platforms.