BlockDAG overview

In a classical blockchain, blocks form a single chain. At very low block times, orphan blocks (valid blocks that do not end up on the longest chain) become more frequent, which can waste work and reduce effective throughput.

XELIS uses a BlockDAG: multiple blocks may exist at the same height, improving scalability and security characteristics compared to a strict linear chain under similar timing assumptions.

Official explanation

Read the official page for precise definitions and diagrams:

• BlockDAG — docs.xelis.io
• Client protocol — how the same transaction may appear in multiple blocks without double-spending

Study questions

1. How does the BlockDAG ordering relate to finality from a wallet perspective?
2. What metrics would you use to compare orphan rates across networks?