A purely internal, proprietary blockchain underpins the Vertalo software model, creating a complex web of relationships between pre-issuance and post-issuance events/objects. As a purpose-built digital asset ledger, this architecture also allows for a consistent, clean mapping between internal events (typically related to the issuance and transfer of shares) and those on the external blockchains with which Vertalo is integrated. As you explore and traverse the Vertalo GraphQL schema exposed through the API, you will see refererences to internal blockchain addresses throughout, and in many use cases these addresses allow you to make connections between various nodes in the graph.
This internal blockchain is integral to the Vertalo architecture regardless of whether you are leveraging an external blockchain (for tokenization, etc.) or not.