> For the complete documentation index, see [llms.txt](https://docs.level.finance/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.level.finance/tutorials/what-is-arbitrum-chain.md).

# What is Arbitrum chain?

Arbitrum is one of the most popular blockchains and Layer 2 and one of the most vibrant ecosystems, in the Top 5 by amount of daily users. Furthermore, Arbitrum is the 4th biggest ecosystem in terms of Total Value Locked (TVL), and volume.