While the blockchain is the innovation that makes LBRY possible, the [Data Network]((/spec/#data) is the layer that actually makes the blockchain useful.

At this level:

• [Metadata]((/spec/#metadata) stored in the blockchain is interpreted and validated.
• [Data referenced by metadata]((/spec/#data) is accessed and distributed via a peer-to-peer network.
• [Identities]((/spec/#channels) are created, signed, and validated.

Data network operations are provided by the lbrysdk. This SDK also provides local wallet functionality and a set of APIs to facilitate building applications.

Additional Resources

• The Specification contains a comprehensive specification of data network operations.
• Resources has further documentation on the LBRY SDK, including its APIs.
• Build teaches you how to create your own app.
• Contribute guides you on how to improve the protocol itself.