选择 Layer 2
权衡取舍
选择 Layer 2 是 CoddyKit 上的免费 Web3 & DApp Development Fundamentals 课时。 这是第 4 节课，共 4 节。 你可以在下方免费阅读本课时的完整内容 — 然后在浏览器中使用内置代码编辑器和全天候 AI 导师进行实践。 这是 Web3 & DApp Development Fundamentals 学习路径的一部分，你的进度在网页和 CoddyKit 应用中同步。 Web3 & DApp Development Fundamentals 课程共包含 4 节课。
本课时的部分内容尚未翻译，以英文显示。
No One-Size-Fits-All L2
There are many Layer 2s, each with different trade-offs. Choosing one means weighing security, cost, speed, and ecosystem.
This lesson gives you a framework to compare them sensibly.
Security Model
The first question is security. Rollups inherit L1 security; sidechains and validiums do not fully.
- ZK rollup: strongest, validity proofs
- Optimistic rollup: strong, fraud proofs
- Sidechain: own validators, weaker
Cost (Gas Fees)
Fees vary widely. L2s that use blobs (post-EIP-4844) and efficient compression are cheaper.
Compare typical swap and transfer costs on each network, not just headline claims.
Finality and Withdrawal Time
How fast can you safely move funds back to L1?
- ZK rollups: fast finality, quick withdrawals
- Optimistic rollups: ~7-day withdrawal (or pay a fast-bridge fee)
If you need to exit quickly, this matters a lot.
EVM Compatibility
EVM equivalence means existing Ethereum contracts and tools work unchanged.
Optimistic rollups (Arbitrum, Optimism) and many ZK rollups now offer strong EVM compatibility, easing migration.
EVM-equivalent L2:
same Solidity, same tooling,
deploy with minimal changesEcosystem and Liquidity
A chain is only as useful as its ecosystem. Check which DEXs, lending markets, and stablecoins are deployed and how much liquidity exists.
Deep liquidity means low slippage and a healthy DeFi environment.
Decentralization of the Sequencer
Most L2s today use a single sequencer to order transactions, which is a centralization risk.
Ask whether the sequencer can censor transactions and whether there is a path to decentralize it and an L1 escape hatch.
Developer Tooling
For builders, consider the availability of RPC providers, block explorers, indexers, oracles, and SDKs.
A mature toolchain accelerates development and reduces friction when shipping a dApp.
Bridges and Onboarding
How easily can users get funds onto the chain? Look at the canonical bridge, supported third-party bridges, and direct fiat on-ramps.
Smooth onboarding strongly affects user adoption.
Matching the L2 to the Use Case
Different needs favor different chains:
- High-value DeFi: prioritize security and liquidity
- Gaming/social: prioritize cheap, fast transactions
- Quick exits: favor ZK rollups
Putting It Together
Choosing an L2 means balancing security model, cost, finality, EVM compatibility, ecosystem, sequencer decentralization, and tooling against your specific use case.
There is no single best L2 — only the best fit. Next course: Cross-Chain and Bridges.
Quick Check
Test your L2 selection reasoning.
Recap: Choosing a Layer 2
You learned to weigh:
- Security model (rollup vs sidechain)
- Cost, finality, and withdrawal time
- EVM compatibility and tooling
- Ecosystem, liquidity, and sequencer decentralization
- Match the L2 to your use case
Course complete! Next: Cross-Chain and Bridges.
常见问题解答
「选择 Layer 2」课时是免费的吗？
是的 — 「选择 Layer 2」的完整文本可在网页上免费阅读。要进行交互式练习（内置代码编辑器和全天候 AI 导师）并解锁 Web3 & DApp Development Fundamentals 课程的其余内容，请升级到 CoddyKit PRO。 Web3 & DApp Development Fundamentals 课程共包含 4 节课。
「选择 Layer 2」这节课中我会学到什么？
权衡取舍 你通过在浏览器中直接运行的动手代码来练习 Web3 & DApp Development Fundamentals，全天候 AI 导师会在你学习这节课的过程中回答你的问题。
学习 Web3 & DApp Development Fundamentals 需要有经验吗？
无需任何先前经验。CoddyKit 上的 Web3 & DApp Development Fundamentals 课程适合初学者到高级学习者，你可以从这里开始或从头开始，按照自己的节奏学习。 这是第 4 节课，共 4 节。
「选择 Layer 2」课时需要多长时间？
大多数 CoddyKit 课程大约需要 5–10 分钟。每节课都很精短且互动，所以你能稳步进步，并在网页和应用中从离开的地方继续。
我能在这节 Web3 & DApp Development Fundamentals 课中编写并运行代码吗？
能。每节 Web3 & DApp Development Fundamentals 课都包含内置代码编辑器，你可以在浏览器中直接编写并运行真实代码，并获得即时 AI 反馈 — 无需本地设置。
此课程中的所有课时
- 为什么需要 Layer 2
- Rollups
- 跨层转移资产
- 选择 Layer 2