This section assumes "blockchain" already means something to you. If you're new, the central problem solved by blockchain is the ability for distributed, disparate entities to all agree on a rivalrous state of affairs. For a thorough introduction to blockchain, start here

LBRY uses a public, proof-of-work blockchain that is very similar to Bitcoin. The blockchain is the foundation of the protocol stack.

The most salient feature of the LBRY blockchain is the association of a normalized string of characters (a "name") with a structured set of metadata. This coupling is called a claim. The content referenced by a claim can be accessed as a LBRY URL, e.g. lbry://hellolbry.

The LBRY blockchain stores names and metadata in a parallel Merkle tree, separate from the tree used to store transaction data. This allows LBRY URLs to be trustfully resolved even without a full copy of the blockchain.

The metadata contains information about the content, such as the title, creator, price (if any), and a unique signature allowing the actual content to be fetched from the data network, the next level in the LBRY stack.

Additional Resources

• The Specification contains a comprehensive documentation of the LBRY blockchain and protocol.
• Resources has documentation about using the LBRY blockchain, including its APIs.