What is Layer 1?
A Layer 1 (L1) is the foundational blockchain in a crypto network — the base layer that processes transactions, reaches consensus, and provides security for everything built on top of it. Layer 1s are responsible for the core functions of a blockchain: ordering transactions, validating them, and ensuring the network’s rules are followed.
Ethereum, Bitcoin, Solana, and Avalanche are all Layer 1 blockchains. Layer 2 networks (Arbitrum, Optimism, Base) build on top of L1s to improve scalability, inheriting the base layer’s security for final settlement.
The term comes from the blockchain scalability stack: Layer 1 handles settlement and security, while Layer 2 handles execution (fast, cheap transactions). Think of L1 as the court system (final authority) and L2 as the day-to-day transactions.
Major Layer 1 Blockchains
| Chain | Consensus | TPS | Finality | TVL | Smart Contracts |
|---|---|---|---|---|---|
| Ethereum | PoS | ~15 | ~12 min (2 epochs) | $50B+ | Yes (Solidity) |
| Solana | PoS + PoH | ~65,000 | ~400ms | $5B+ | Yes (Rust) |
| Avalanche | Snowball | ~4,500 | ~1-2 sec | $1B+ | Yes (Solidity) |
| BNB Chain | PoSA (delegated PoS) | ~2,200 | ~3 sec | $5B+ | Yes (Solidity) |
| Sui | PoS (Narwhal-Bullshark) | ~100,000+ | ~400ms | $500M+ | Yes (Move) |
| Aptos | PoS | ~100,000+ | ~1 sec | $400M+ | Yes (Move) |
| Bitcoin | PoW | ~7 | ~60 min (6 blocks) | N/A | No (Script, limited) |
| Cosmos | PoS (Tendermint) | ~10,000 | ~6 sec | $1B+ | Yes (CosmWasm) |
The Blockchain Trilemma
Ethereum co-founder Vitalik Buterin coined the blockchain trilemma: you can optimize for two of three properties, but not all three simultaneously:
| Property | Description | Trade-off |
|---|---|---|
| Security | Resistance to attacks, censorship | Higher security = fewer validators = less decentralization |
| Decentralization | Number of independent participants | More decentralization = lower throughput |
| Scalability | Transaction throughput (TPS) | Higher TPS = larger hardware requirements = less decentralization |
How Different L1s Approach the Trilemma
- Ethereum: Prioritizes security and decentralization over scalability. Low TPS (~15) but unmatched security ($100B+ staked). Relies on L2s for scaling.
- Solana: Prioritizes scalability and security. Very high TPS (~65K) but requires more expensive hardware (high-end servers), reducing decentralization.
- BNB Chain: Prioritizes scalability. 21 validators (highly centralized) but fast and cheap.
- Sui/Aptos: Prioritize scalability with parallel execution. Novel consensus enables high TPS without sacrificing security.
No L1 has solved the trilemma completely. The current approach (Ethereum’s) uses L2s to handle scalability while L1 focuses on security and decentralization.
How Layer 1s Differ
Consensus Mechanisms
See our dedicated guides:
- Proof of Stake — Ethereum’s approach
- Proof of Work — Bitcoin’s approach
- BFT — Byzantine Fault Tolerance
Smart Contract Support
| Chain | Language | EVM Compatible? | DeFi Ecosystem |
|---|---|---|---|
| Ethereum | Solidity, Vyper | Native | Largest |
| Arbitrum/Optimism/Base | Solidity, Vyper | Yes (L2) | Growing |
| Solana | Rust | No | Growing |
| Avalanche | Solidity | Yes (C-Chain) | Medium |
| Sui | Move | No | Emerging |
| Aptos | Move | No | Emerging |
| Bitcoin | Script, Taproot | No | Minimal (Ordinals, Stacks) |
Token Economics
L1 tokens serve multiple purposes:
- Gas payment: Pay for transaction execution
- Staking: Secure the network and earn rewards
- Governance: Vote on protocol upgrades
- Store of value: Speculative and utility value
L1 Security Comparison
| Chain | Staked Value | Attack Cost | Time to Finality | Decentralization Score |
|---|---|---|---|---|
| Ethereum | $100B+ (34M ETH) | $34B+ (slashing risk) | 12.8 min | High (1M+ validators) |
| Solana | $7B+ (SOL staked) | $7B+ | 400ms | Medium (1,800 validators) |
| Avalanche | $3B+ (AVAX staked) | $3B+ | 1-2 sec | Medium (1,600 validators) |
| BNB | $500M+ | $500M+ | 3 sec | Low (21 validators) |
The L1 vs L2 Relationship
L1s and L2s are complementary, not competing:
User → L2 (fast, cheap execution)
↓ (batch + post)
L1 (security, settlement)L1 provides:
- Final settlement: The ultimate source of truth
- Security: Cryptographic guarantees via consensus
- Data availability: Ensures transaction data is available for verification
L2 provides:
- Speed: 100-4,000 TPS vs 15 TPS on L1
- Low cost: $0.01-0.50 vs $1-50 on L1
- User experience: Near-instant confirmations
Frequently Asked Questions
Q: Which Layer 1 is the best? A: Depends on your priorities. For DeFi and security: Ethereum. For speed and low fees: Solana. For EVM compatibility: Ethereum + L2s. For diversification: Cosmos ecosystem.
Q: Can Layer 1s compete with L2s? A: They serve different roles. L1s settle and secure; L2s execute. Some L1s (Solana) handle execution directly, but Ethereum’s L2-centric approach is gaining dominance.
Q: How many Layer 1s are there? A: Hundreds, but only ~15 have meaningful TVL (> $100M) and user activity. The rest are speculative or regional chains.