Layer 1 vs Layer 2
Layer 1s are base blockchains like Bitcoin and Ethereum, while Layer 2s build on top to add speed and reduce costs. You'll learn why both layers matter and how they interact.
Who Is This For?
- •Beginners who feel fees are high on main chains
- •Users deciding whether to transact on Ethereum L1 or L2s like Arbitrum or Optimism
Learning Objectives
- 01Differentiate L1 security from L2 scalability roles
- 02Describe how transactions settle back to the base chain
- 03Choose when to stay on L1 versus move to L2
What Defines a Layer 1
Layer 1 is the foundation--the base blockchain that provides security, consensus, and data availability. Everything else builds on top of it.
🏗️ The Foundation Layer
L1 Advantages
- •Highest security and decentralization
- •Deepest liquidity and most integrations
- •True finality--no additional trust assumptions
L1 Limitations
- •Higher fees during network congestion
- •Limited throughput (transactions per second)
- •Slower block times compared to L2s
How Layer 2s Work
Layer 2s process transactions off the main chain, then post compressed proofs back to L1. This dramatically increases throughput while inheriting L1 security.
🔄 The Rollup Process
🟡 Optimistic Rollups
Assume transactions are valid by default. Include a challenge period where anyone can dispute fraud.
Withdrawals: ~7 day challenge period
Security: Fraud proofs
🟣 ZK Rollups
Generate cryptographic proofs (zero-knowledge) that transactions are valid. No challenge period needed.
Withdrawals: Minutes to hours
Security: Validity proofs
💰 Cost Comparison Calculator
See how much you'd save on L2. Select a transaction type:
💡 You'd save $15.38 (99% less) on L2
🌉 Bridge Simulator
See how bridging works in each direction. Notice the different withdrawal times!
When to Use Each
The right layer depends on your use case. Let's build intuition with real scenarios.
📊 L1 vs L2 Comparison
| Attribute | Layer 1 | Layer 2 |
|---|---|---|
| Security | Maximum (consensus layer) ✓ | Inherits from L1 |
| Transaction Cost | $5-50+ | $0.01-0.50 ✓ |
| Speed | 12-15 seconds | 1-2 seconds ✓ |
| Liquidity | Highest ✓ | Growing |
| Decentralization | Most decentralized ✓ | Varies by design |
| Throughput | ~15-30 TPS | ~2,000+ TPS ✓ |
🎯 Which Layer? (Click to reveal)
✅ Use L1 When:
- •Making large, high-value transfers
- •Minting valuable NFTs where provenance matters
- •Maximum security and finality are critical
- •Interacting with L1-only protocols
✅ Use L2 When:
- •Making frequent, smaller transactions
- •Trading actively on DEXs
- •Playing blockchain games
- •Experimenting with new protocols
Common Mistakes & Gotchas
These misconceptions about L1s and L2s can lead to lost funds or unexpected delays.
⚠️ Pro tip: Before bridging, always verify bridge addresses through official documentation. Bookmark official bridge URLs and never use links from Discord DMs or Twitter ads.
Knowledge Check
Let's see how well you understand Layer 1 vs Layer 2. Answer all 5 questions below.
What core role does a Layer 1 chain provide?
How do rollups reduce fees?
Why do some L2 withdrawals take several days?
When should you prefer using Layer 1 over Layer 2?
What is the key difference between a sidechain and a rollup?