A layer-1, or L1, blockchain is the base network of a blockchain ecosystem. It operates independently—without relying on other chains for validation or execution—and handles everything from transaction processing to consensus and data storage on its own ledger.
Often called the mainnet or settlement layer, a layer-1 blockchain forms the ground floor upon which all other blockchain layers, including sidechains and layer-2s, are built.
Where layer-2s extend performance on top of existing networks, layer-1s stand alone. They define their own rules, run their own validators, and issue their own native tokens. Bitcoin, Ethereum, Solana, Cardano, and Avalanche all fit this description.
In this article, we will look at the history and functions of the foundational layer of Web3.
Every L1 blockchain includes several core components that make it both functional and secure:
Across different networks, the flow is broadly the same:
This cycle repeats continuously, thousands of times per day, without central oversight.
The consensus mechanism defines how a blockchain reaches agreement and shapes its speed, security, and energy profile. While there are many different consensus mechanisms, the main ones are:
Bitcoin (BTC) – Proof of Work: The first and most secure blockchain. Processes about 7 TPS using energy-intensive mining, emphasizing decentralization and immutability over speed.
Ethereum (ETH) – Proof of Stake: The largest programmable blockchain, supporting smart contracts, NFTs, and DeFi. After The Merge in 2022, it reduced energy use by more than 99% while laying the groundwork for scalability through rollups and upcoming sharding.
Solana (SOL) – Proof of History + PoS: Known for high throughput and low fees, Solana timestamps transactions before consensus to achieve sub-second block times.
Cardano (ADA) – Ouroboros Proof of Stake: A research-driven blockchain that emphasizes formal verification and layered architecture to separate settlement and computation.
Avalanche (AVAX) – Avalanche Consensus: Uses probabilistic sampling to reach consensus quickly. Offers sub-second finality and supports customizable subnets for app-specific chains.
Binance Smart Chain (BNB) – Delegated Proof of Stake: Operated by a limited validator set, BSC trades decentralization for performance, providing fast, low-cost transactions compatible with Ethereum’s tooling.
Each blockchain aims to tackle the same underlying challenge: the blockchain trilemma.
Ethereum co‑founder Vitalik Buterin coined the term “blockchain trilemma” in 2017 to describe the challenge that blockchains cannot simultaneously maximize decentralization, scalability, and security, forcing trade‑offs between the three.
Developers continually search for ways to boost blockchain throughput without compromising decentralization—a direct response to the blockchain trilemma.
Layer-1 blockchains supported DeFi, powering lending, exchanges, and stablecoins through smart contracts. Ethereum and Solana enabled NFTs and gaming, bringing digital ownership on-chain. They also improved supply-chain transparency, secured digital identity, and enabled tokenization of real-world assets like property and art.
Layer-2s and sidechains help with speed, but layer-1s remain the source of truth. They provide final settlement, immutable history, and shared trust for everything built above them.
Blockchain technology has advanced far beyond its 2009 origins, and the work hasn’t slowed. In November, the Ethereum Foundation announced its next major step: the Ethereum Interoperability Layer, which would let any Ethereum L2 communicate with any other L2 instantly.
As blockchain technology evolves—from energy-heavy mining to modular, quantum-resistant architectures—layer-1 blockchains continue to define the infrastructure of the decentralized internet.
