Layer 0 (L0)

To understand Layer 0, picture the blockchain ecosystem as a stack of infrastructure, much like the internet itself is built in layers. At the very bottom sits Layer 0 — the foundational communication and interoperability infrastructure that different blockchains can be built upon or connected through. While a Layer 1 blockchain like Ethereum is a self-contained network, a Layer 0 protocol is the substrate that makes it possible for multiple independent blockchains to exist, communicate, and share data with each other.

Layer 0 projects typically provide the raw networking layer, consensus coordination, and cross-chain communication tools that developers use to launch their own specialized blockchains. Instead of building on top of Ethereum and inheriting all of its constraints, a developer using a Layer 0 protocol can spin up an entirely custom blockchain — with its own rules, speed, and governance — while still being able to exchange messages and value with other chains in the same ecosystem. Polkadot and Cosmos are among the most well-known examples. Without something like Layer 0, each blockchain is an island — Bitcoin cannot natively talk to Ethereum, and Ethereum cannot natively talk to Solana.

Example: Imagine the internet itself as a Layer 0. Individual websites (like Google or Wikipedia) are built on top of it, but they all rely on the same underlying protocols — TCP/IP — to communicate. Layer 0 blockchains aim to be that shared foundation for the crypto world, enabling individual blockchains to interoperate the way websites do on the internet today.