What Is a Layer 1 Blockchain?

A Layer 1 is a base blockchain that settles its own transactions. It runs its own consensus, maintains its own state and does not depend on another chain for security. Bitcoin, Ethereum, Solana and BNB Chain are all Layer 1 networks. The term only really makes sense in contrast to Layer 2, which are networks that process transactions elsewhere and post the results back down to a Layer 1.

What Makes a Chain a Layer 1

Three things. It produces its own blocks, it reaches consensus among its own validator set, and it has a native asset used to pay for transactions. Everything beyond that varies enormously. Some Layer 1s are EVM compatible, meaning contracts written for Ethereum run on them with little or no modification, which is why so many chains chose that path. Others, Solana among them, use a different execution environment entirely and require their own tooling and their own developer ecosystem.

Layer 1 Versus Layer 2

A Layer 2 does not replace the base chain, it borrows its security. Rollups such as Arbitrum and Base execute transactions off-chain, compress them, and post proofs or data back to Ethereum, which remains the final arbiter of what happened. The result is cheaper and faster transactions that still inherit Ethereum’s settlement guarantees. The cost is extra complexity and, in most designs, a waiting period when withdrawing back down to the base layer.

The Trade-offs Every Layer 1 Faces

Layer 1 design is a balancing act between decentralization, security and throughput, often called the blockchain trilemma. Pushing throughput usually means fewer or better-resourced validators, which concentrates control. Maximizing decentralization tends to cap how fast the network can go. Every Layer 1 picks a point on that curve, and that single choice explains most of the visible differences between them, from block times to hardware requirements to how many nodes actually run the software.

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