Layer 1 and Layer 2: what they are and why they exist
If you spend any time reading about cryptocurrency, you will quickly encounter the terms Layer 1 and Layer 2. They appear in news articles, developer discussions and investment reports, usually without explanation. This post covers what Layer 1 and Layer 2 actually mean. It explains why the distinction exists and what it matters for anyone using or investing in crypto in the UK.
What Layer 1 blockchains are
To understand Layer 1 and Layer 2, start at the bottom of the stack. A Layer 1 is the base blockchain: the foundation on which everything else is built. Bitcoin is a Layer 1. Ethereum is a Layer 1.
Solana, Avalanche and Cardano are also Layer 1s. These are the networks that process and record transactions directly on the chain. Each one runs independently, with its own rules, its own nodes, and its own method for reaching consensus.
Each Layer 1 sets the core rules for its network. It decides how transactions are validated, how new coins are created, and what happens when nodes disagree. Think of the Layer 1 as the constitution of a country.
Every application and transaction built on that network has to operate within those rules. Nothing overrides the base layer. That is both its greatest strength and its most significant constraint.
The speed problem at the heart of Layer 1 and Layer 2
Bitcoin processes around seven transactions per second. Ethereum handles somewhere between fifteen and thirty. Visa processes tens of thousands per second. If cryptocurrency is going to work at the scale of global payments, Layer 1 blockchains cannot handle the volume alone.
One option is to make the base layer faster. Speed gains on a Layer 1 typically come at the cost of decentralisation or security. The tradeoff is genuine and unavoidable.
This tradeoff has a name in the crypto world: the blockchain trilemma. It describes the difficulty of achieving security, decentralisation and scalability all at once on a single Layer 1. Improve one and you typically weaken another.
The trilemma is why Layer 2 solutions exist in the first place. No one has solved it at the base layer yet.
You can design a faster blockchain. But it usually means fewer nodes, more centralised control, or weaker guarantees. Most of the networks that have taken this path have faced serious questions about reliability and trust.
The other option is to build a second layer on top. It handles everyday transactions at volume, then settles back to the base layer when needed. That is the idea behind the Layer 1 and Layer 2 model.
The base layer stays slow and secure. The second layer absorbs the volume. Both do the job they were designed for, without either one having to compromise.
How Layer 2 networks work in practice
A Layer 2 is a network built on top of a Layer 1. It processes transactions faster and more cheaply than the base layer. But it ultimately settles back onto the base chain.
Think of the Layer 1 as the M25, the major ring road that everything eventually passes through. The Layer 2 is the faster network of local roads that handles most daily journeys. The motorway provides the final, secure settlement. Both are necessary parts of the same system.
The Lightning Network is Bitcoin’s most established Layer 2. Two parties open a payment channel between themselves. They transact as many times as they like, instantly and cheaply. Then they settle the final balance back on the Bitcoin blockchain when the channel closes.
Hundreds of transactions can happen off-chain. Only the channel opening and closing are recorded on the Layer 1. This is how paying for coffee with Bitcoin works in certain cafes. Those payments never touch the base layer at all.
Ethereum’s Layer 2 landscape is larger and growing quickly. Networks called Arbitrum, Optimism and Base process transactions at a fraction of Ethereum’s cost. They bundle transactions together and settle them back on Ethereum in batches.
By 2025, the majority of Ethereum activity by transaction count was happening on Layer 2 networks rather than the main chain. That shift happened faster than most analysts expected. Most people using Ethereum-based apps are already on a Layer 2. Wallets and apps handle the routing automatically, so most users never notice.
Understanding what smart contracts do helps explain why Layer 2 networks have grown so fast. The post on what smart contracts are and how they work explains the mechanism that most Layer 2 settlement processes depend on.
Common misconceptions about Layer 1 and Layer 2
The first misconception is that using a Layer 2 means leaving the security of the base blockchain behind. It does not. A well-designed Layer 2 inherits the security of the Layer 1 it settles on.
You gain speed and lower fees while giving up very little in terms of final settlement guarantees. The relationship between Layer 1 and Layer 2 is a division of labour, not a compromise on security.
The second misconception is that one Layer 2 will eventually dominate and the rest will disappear. Nobody knows how this plays out. There is genuine competition between different Layer 2 designs.
Each design makes different technical choices about security and settlement. It is possible that several Layer 2 networks coexist for years. It is also possible that one proves more efficient and absorbs the rest. Anyone who tells you they know for certain is overstating what is known.
The third misconception is that decentralised finance, or DeFi, runs only on Layer 1 blockchains. A large portion of DeFi activity now happens on Layer 2 networks, not the base layer directly. The post on what decentralised finance actually is and how it works explains the broader landscape and which networks host most of that activity.
What Layer 1 and Layer 2 mean for UK crypto users
For most people in the UK, the Layer 1 and Layer 2 distinction is already handled on their behalf. If you notice a transaction going through Arbitrum, Optimism or Base rather than Ethereum directly, you are on a Layer 2. Fees will be lower and transactions faster.
The trust model is slightly more complex than using the base chain directly. But most everyday users will never encounter that complexity in practice. Wallets and apps abstract it away entirely.
The Ethereum Foundation’s Layer 2 resource page provides a detailed technical overview for those who want to go deeper. It covers how rollup technology works and which networks have been independently audited for security.
The broader lesson from Layer 1 and Layer 2 is that crypto is no longer a single flat system. It has become a layered infrastructure, similar in structure to the internet itself. Different levels solve different problems. Base layers provide security and finality.
Middle layers provide speed and low cost. Applications sit on top and manage the complexity so users do not have to. Whether this layered infrastructure will scale to serve a global financial system is an important open question. It is worth watching as the technology develops.
This article is for informational purposes only and does not constitute financial advice. Cryptocurrency investments carry significant risk. Always do your own research before making any financial decisions.