Layer 1 (L1) is the base protocol of a blockchain network. It maintains the network’s main transaction state and applies its own rules for validating transactions and reaching consensus. Bitcoin and Ethereum mainnet are familiar examples, although their designs and purposes differ.
“Layer 1” is a useful way to distinguish a base network from systems built to scale or extend it. The term does not imply that all L1s work alike, are equally decentralized, or offer the same security.
What the Base Layer Does
An L1’s nodes check transactions and blocks according to the network’s protocol. Its consensus process determines which valid history the network accepts. The details vary: Bitcoin’s proof-of-work system and Ethereum’s proof-of-stake system use different mechanisms and assumptions.
Some L1s also run general-purpose smart contracts; others focus on a narrower set of functions. Throughput, confirmation or finality, data storage, validator or miner requirements, and the ability to verify the system independently are all part of a network’s design. A single transactions-per-second figure cannot capture those differences unless the measurement method and transaction type are also specified.
Layer 1 and Layer 2
A Layer 2 is intended to handle some activity away from a base network while relying on that network in defined ways. On Ethereum, rollups execute transactions outside the main chain and post data or proofs back to Ethereum. That differs from a sidechain or a system that uses a separate data-availability committee; those designs make different security trade-offs.
For that reason, “built on top of” does not by itself tell you what security an application inherits. Check where transactions are executed, what data is posted to the L1, how disputes or invalid updates are handled, who can operate or upgrade the system, and what users must do to exit. Ethereum’s documentation describes several scaling designs separately because their trust assumptions are not interchangeable.
Design Trade-offs
Discussions of L1s often group design goals under decentralization, security, and scalability. This “blockchain trilemma” is a way to discuss competing priorities, not a universal theorem that every network must optimize exactly two properties. Comparing chains requires looking at concrete choices: hardware needed to run a node, validator concentration, consensus rules, network performance under load, and recovery or governance procedures.
Similarly, calling a chain “fast,” “cheap,” or “secure” is incomplete without a measurement and a threat model. A higher throughput claim may use a different transaction mix, rely on particular hardware, or describe a short peak rather than sustained activity. Readers should compare like with like and separate a protocol’s design from marketing claims.
Common Misconceptions
“Every chain that connects to Ethereum is an Ethereum Layer 2.” No. Sidechains and other connected systems can use independent consensus or data availability. A bridge or shared user interface does not make their security identical to Ethereum’s.
“Layer 2 always inherits all Layer 1 security.” Not automatically. The answer depends on the specific design and its proof, data, upgrade, and exit mechanisms. Even within one ecosystem, systems can make different trust assumptions.
“The highest TPS number identifies the best Layer 1.” A throughput number alone leaves out decentralization, reliability, transaction mix, costs, and finality. It is one measurement, not a complete comparison.
Social Media Sentiment
An October 2026 r/ethereum daily discussion included a question about which networks capture value at the base layer and debate over whether Ethereum’s Layer 2 adoption also benefits L1. This is one discussion, not a poll; it shows that people debate both technical scaling and the economic role of the base chain. Read the Reddit discussion.
Last updated: 2026-10
Related Terms
See Also
- Are Layer 2 Networks Actually Decentralized?
- Does Ethereum TPS Include Layer 2 Transactions?
- Is Ethereum Staking Making the Network More Centralized?
- Swap crypto with ChangeNOW
Sources
- Bitcoin Developer Guide, “Block Chain” — Explains how Bitcoin nodes validate blocks and follow the network’s consensus rules.
- Ethereum.org, “Scaling” — Distinguishes Layer 1 protocol changes from off-chain scaling designs and explains why different Layer 2 models have different security assumptions.
- Ethereum.org, “Data Availability” — Describes why rollups need data to be available for independent verification and how that relates to Ethereum’s base layer.