[{"type":"paragraph","children":[{"text":"This lesson sits on the deeper side of blockchain fundamentals. Please read it carefully: it focuses on terms like Layer 0, Layer 1, Layer 2. The concepts themselves aren’t hard, but truly grasping them takes a bit of time."}]},{"type":"paragraph","children":[{"text":""}]},{"type":"paragraph","children":[{"text":"Think of them as the “layered blueprint” of blockchains—how the whole system runs, scales, and supports apps. If you’re new, these terms can feel confusing:"}]},{"type":"bulleted-list","children":[{"type":"list-item","children":[{"type":"paragraph","children":[{"text":"Layer 0: the infrastructure layer—the “foundation” of the blockchain world; you can loosely think of it as the internet itself."}]}]},{"type":"list-item","children":[{"type":"paragraph","children":[{"text":"Layer 1: the base (L1) chains—the “main building,” akin to the TCP/IP suite on the internet."}]}]},{"type":"list-item","children":[{"type":"paragraph","children":[{"text":"Layer 2: the scaling layer—like adding external elevators to the building for efficiency; loosely analogous to a content delivery network (CDN)."}]}]},{"type":"list-item","children":[{"type":"paragraph","children":[{"text":"Layer 3: the application layer—built atop the infrastructure and base layers, where users actually interact. (Strictly speaking, “Layer 3” is not an industry-standard term, but it’s helpful for understanding. Think DeFi, NFT, etc.)"}]}]}]},{"type":"paragraph","children":[{"text":"Below, we’ll walk through each layer in the most intuitive way possible—and how they work in practice."}]},{"type":"paragraph","children":[{"text":"Why Split Blockchains into Layers?"}]},{"type":"paragraph","children":[{"text":""}]},{"type":"paragraph","children":[{"text":"In the early days there was only a single-chain world—Bitcoin. It did one thing: peer-to-peer transfers. It’s admired for stability and decentralization, but its functionality was very limited."}]},{"type":"paragraph","children":[{"text":""}]},{"type":"paragraph","children":[{"text":"Then Ethereum arrived with smart contracts. DeFi, NFTs, and other innovations exploded—along with congestion and fees. In 2017, CryptoKitties almost brought Ethereum to its knees; during DeFi Summer 2020, gas fees ran into the hundreds of dollars."}]},{"type":"paragraph","children":[{"text":""}]},{"type":"paragraph","children":[{"text":"That pain forced a question: Can we decouple roles? Let the bottom handle security and consensus, let the middle handle scale and interaction, and let the top focus on user experience. Over time, a layered design emerged:"}]},{"type":"bulleted-list","children":[{"type":"list-item","children":[{"type":"paragraph","children":[{"text":"Layer 0 — cross-chain communication and low-level protocols, like the TCP/IP of Web3."}]}]},{"type":"list-item","children":[{"type":"paragraph","children":[{"text":"Layer 1 — the base chains themselves: Bitcoin, Ethereum, Solana, etc."}]}]},{"type":"list-item","children":[{"type":"paragraph","children":[{"text":"Layer 2 — scaling solutions attached to L1 to relieve bottlenecks."}]}]},{"type":"list-item","children":[{"type":"paragraph","children":[{"text":"Application layer — end-user experiences such as DeFi, NFT, GameFi, social."}]}]}]},{"type":"paragraph","children":[{"text":"This decoupling means each layer can optimize independently while cooperating end-to-end. Users won’t need to care what “layer” they’re on; for the industry, layering is how the Web3 skyscraper stays sturdy."}]},{"type":"paragraph","children":[{"text":"A Closer Look at Each Layer"}]},{"type":"heading-three","children":[{"text":""}]},{"type":"heading-three","children":[{"text":"1) Layer 0 — The Foundation of Blockchains"}]},{"type":"paragraph","children":[{"text":"1.1 Definition Layer 0 covers cross-chain communication and the foundational protocols. It doesn’t offer user-facing asset transfers like Bitcoin; instead, it provides the roads and bridges connecting chains. If blockchains are cities, Layer 0 is the highways, rail lines, and fiber. Without it, cities stay isolated."}]},{"type":"paragraph","children":[{"text":"1.2 Core Mechanics"}]},{"type":"bulleted-list","children":[{"type":"list-item","children":[{"type":"paragraph","children":[{"text":"Consensus & networking protocols — keep data consistent when chains communicate."}]}]},{"type":"list-item","children":[{"type":"paragraph","children":[{"text":"Cross-chain mechanisms — let different blockchains pass messages or assets."}]}]},{"type":"list-item","children":[{"type":"paragraph","children":[{"text":"Modular architecture — toolkits to help developers spin up new chains quickly."}]}]}]},{"type":"paragraph","children":[{"text":"1.3 Representative Projects"}]},{"type":"bulleted-list","children":[{"type":"list-item","children":[{"type":"paragraph","children":[{"text":"Polkadot (DOT): relay chain + parachains for interoperability."}]}]},{"type":"list-item","children":[{"type":"paragraph","children":[{"text":"Cosmos (ATOM): IBC protocol for cross-chain messaging."}]}]},{"type":"list-item","children":[{"type":"paragraph","children":[{"text":"Avalanche Subnets: custom subnets enabling “multi-chain in parallel.”"}]}]}]},{"type":"paragraph","children":[{"text":"1.4 Advantages"}]},{"type":"bulleted-list","children":[{"type":"list-item","children":[{"type":"paragraph","children":[{"text":"Breaks down chain silos and enables interoperability."}]}]},{"type":"list-item","children":[{"type":"paragraph","children":[{"text":"Gives developers greater flexibility."}]}]},{"type":"list-item","children":[{"type":"paragraph","children":[{"text":"Improves ecosystem-level scalability."}]}]}]},{"type":"paragraph","children":[{"text":"1.5 Limitations"}]},{"type":"bulleted-list","children":[{"type":"list-item","children":[{"type":"paragraph","children":[{"text":"Growth depends on ecosystem adoption; great tech without builders still stalls."}]}]},{"type":"list-item","children":[{"type":"paragraph","children":[{"text":"Low user visibility; many people don’t realize their apps rely on L0 underneath."}]}]}]},{"type":"paragraph","children":[{"text":"1.6 Analogy TCP/IP turned isolated LANs into the global internet. Polkadot and Cosmos aim to be Web3’s TCP/IP."}]},{"type":"paragraph","children":[{"text":"2) Layer 1 — The Main Building"}]},{"type":"paragraph","children":[{"text":"2.1 Definition Layer 1 is the base chain itself—handling transactions and block production. Bitcoin, Ethereum, BNB Chain, Solana are all L1s. If Layer 0 is the foundation, Layer 1 is the city’s buildings—the most visible infrastructure."}]},{"type":"paragraph","children":[{"text":"2.2 Core Tasks"}]},{"type":"bulleted-list","children":[{"type":"list-item","children":[{"type":"paragraph","children":[{"text":"Accounting & security — how transactions are batched and consensus reached."}]}]},{"type":"list-item","children":[{"type":"paragraph","children":[{"text":"Smart contracts — allowing developers to deploy DApps."}]}]},{"type":"list-item","children":[{"type":"paragraph","children":[{"text":"Governance — upgrades, forks, and community decision-making."}]}]}]},{"type":"paragraph","children":[{"text":"2.3 Representative Projects"}]},{"type":"bulleted-list","children":[{"type":"list-item","children":[{"type":"paragraph","children":[{"text":"Bitcoin: digital gold—the most secure value network."}]}]},{"type":"list-item","children":[{"type":"paragraph","children":[{"text":"Ethereum: smart-contract pioneer; birthplace of DeFi/NFT."}]}]},{"type":"list-item","children":[{"type":"paragraph","children":[{"text":"BNB Chain: high throughput, low fees; supports many apps."}]}]},{"type":"list-item","children":[{"type":"paragraph","children":[{"text":"Solana: high concurrency; fits games and NFT activity."}]}]},{"type":"list-item","children":[{"type":"paragraph","children":[{"text":"Aptos / Sui: Move-based, emphasize safety and scalability."}]}]}]},{"type":"paragraph","children":[{"text":"2.4 Strengths & Challenges"}]},{"type":"paragraph","children":[{"text":"Strengths"}]},{"type":"bulleted-list","children":[{"type":"list-item","children":[{"type":"paragraph","children":[{"text":"Preserve decentralization and security."}]}]},{"type":"list-item","children":[{"type":"paragraph","children":[{"text":"Large developer ecosystems."}]}]}]},{"type":"paragraph","children":[{"text":"Challenges"}]},{"type":"bulleted-list","children":[{"type":"list-item","children":[{"type":"paragraph","children":[{"text":"Limited performance (low TPS)."}]}]},{"type":"list-item","children":[{"type":"paragraph","children":[{"text":"High gas can block mass adoption."}]}]},{"type":"list-item","children":[{"type":"paragraph","children":[{"text":"Popular chains are prone to congestion."}]}]}]},{"type":"paragraph","children":[{"text":"2.4.3 Example During 2020’s DeFi boom, users bid up gas fees into the hundreds just to get in line—people joked “on-chain ops cost more than attorney fees.” That’s the L1 bottleneck in a nutshell."}]},{"type":"paragraph","children":[{"text":"3) Layer 2 — The External Elevators"}]},{"type":"paragraph","children":[{"text":"3.1 Definition Layer 2 sits atop Layer 1 to scale it: alleviate congestion, cut fees, and improve UX. Picture external elevators bolted to a high-rise, so people don’t all jam the stairwell."}]},{"type":"paragraph","children":[{"text":"3.2 Core Mechanics"}]},{"type":"bulleted-list","children":[{"type":"list-item","children":[{"type":"paragraph","children":[{"text":"Rollups"}]}]},{"type":"bulleted-list","children":[{"type":"list-item","children":[{"type":"paragraph","children":[{"text":"Optimistic Rollup: assume validity; revert only on proven fraud."}]}]},{"type":"list-item","children":[{"type":"paragraph","children":[{"text":"ZK Rollup: verify batches with zero-knowledge proofs; higher assurance."}]}]}]},{"type":"list-item","children":[{"type":"paragraph","children":[{"text":"State channels: settle many off-chain interactions, post final state on-chain."}]}]},{"type":"list-item","children":[{"type":"paragraph","children":[{"text":"Sidechains: separate chains linked to the main chain."}]}]}]},{"type":"paragraph","children":[{"text":"3.3 Advantages"}]},{"type":"bulleted-list","children":[{"type":"list-item","children":[{"type":"paragraph","children":[{"text":"Massively higher throughput and lower costs."}]}]},{"type":"list-item","children":[{"type":"paragraph","children":[{"text":"Inherit L1 security (especially rollups)."}]}]},{"type":"list-item","children":[{"type":"paragraph","children":[{"text":"More design choices for developers."}]}]}]},{"type":"paragraph","children":[{"text":"3.4 Challenges"}]},{"type":"bulleted-list","children":[{"type":"list-item","children":[{"type":"paragraph","children":[{"text":"UX can still be complex (bridges, funding on L2, withdrawals)."}]}]},{"type":"list-item","children":[{"type":"paragraph","children":[{"text":"Dependence on L1; not fully standalone."}]}]}]},{"type":"paragraph","children":[{"text":"3.5 Examples"}]},{"type":"bulleted-list","children":[{"type":"list-item","children":[{"type":"paragraph","children":[{"text":"Arbitrum / Optimism: star L2s for Ethereum."}]}]},{"type":"list-item","children":[{"type":"paragraph","children":[{"text":"zkSync: a leading ZK Rollup with significant future potential."}]}]}]},{"type":"paragraph","children":[{"text":"Analogy If Ethereum is a downtown skyscraper, L2s are the high-speed exterior elevators letting far more people move efficiently."}]},{"type":"paragraph","children":[{"text":"4) The Application Layer — Where Life Happens"}]},{"type":"paragraph","children":[{"text":"4.1 Definition This is what users actually touch. Apps (DApps) and on-chain services built atop L0/L1/L2. If the blockchain is a city, apps are the malls, schools, housing, parks—where people spend time, transact, and play."}]},{"type":"paragraph","children":[{"text":"4.2 Categories"}]},{"type":"bulleted-list","children":[{"type":"list-item","children":[{"type":"paragraph","children":[{"text":"DeFi — Uniswap, Aave."}]}]},{"type":"list-item","children":[{"type":"paragraph","children":[{"text":"NFT — OpenSea, Blur."}]}]},{"type":"list-item","children":[{"type":"paragraph","children":[{"text":"GameFi — Axie Infinity, StepN."}]}]},{"type":"list-item","children":[{"type":"paragraph","children":[{"text":"SocialFi — Lens Protocol, friend.tech."}]}]},{"type":"list-item","children":[{"type":"paragraph","children":[{"text":"RWA — tokenized real-world assets: real estate, bonds, art."}]}]},{"type":"list-item","children":[{"type":"paragraph","children":[{"text":"Metaverse — Decentraland, The Sandbox."}]}]}]},{"type":"paragraph","children":[{"text":"4.3 Core Logic"}]},{"type":"bulleted-list","children":[{"type":"list-item","children":[{"type":"paragraph","children":[{"text":"Identity: decentralized identity (DID) proves who you are."}]}]},{"type":"list-item","children":[{"type":"paragraph","children":[{"text":"Assets: NFTs and tokens grant true ownership."}]}]},{"type":"list-item","children":[{"type":"paragraph","children":[{"text":"Economy: token incentives, DAO governance, DeFi financing."}]}]}]},{"type":"paragraph","children":[{"text":"4.4 Examples"}]},{"type":"bulleted-list","children":[{"type":"list-item","children":[{"type":"paragraph","children":[{"text":"Uniswap: redefined “exchange”—anyone can be a market maker."}]}]},{"type":"list-item","children":[{"type":"paragraph","children":[{"text":"Axie Infinity: enabled real income for players in Southeast Asia."}]}]},{"type":"list-item","children":[{"type":"paragraph","children":[{"text":"Decentraland: kicked off a digital real-estate market."}]}]}]},{"type":"paragraph","children":[{"text":"4.5 What’s Next"}]},{"type":"bulleted-list","children":[{"type":"list-item","children":[{"type":"paragraph","children":[{"text":"Super apps: WeChat-like bundles—wallet, payments, social, games, investing."}]}]},{"type":"list-item","children":[{"type":"paragraph","children":[{"text":"On-chain ↔ real-world: RWA brings real assets on-chain."}]}]},{"type":"list-item","children":[{"type":"paragraph","children":[{"text":"AI + blockchain: smart contracts plus AI for self-running economies."}]}]}]},{"type":"paragraph","children":[{"text":"The app layer’s vibrancy is how users feel Web3’s value."}]},{"type":"paragraph","children":[{"text":""}]},{"type":"paragraph","children":[{"text":"Cross-Layer Coordination & Where It’s Going"}]},{"type":"paragraph","children":[{"text":""}]},{"type":"paragraph","children":[{"text":"As layering matures, the industry is entering a modular era. Rather than one chain doing everything, we’re seeing separation of concerns with cross-layer cooperation. The three core modules—consensus, execution, data availability—are being split and optimized. This makes the system more flexible and gives both developers and users a stronger foundation."}]},{"type":"paragraph","children":[{"text":""}]},{"type":"paragraph","children":[{"text":"For example, Ethereum L1 focuses on security and settlement, L2 handles high-frequency execution, and DA layers provide scalable data availability. This division of labor resembles a distributed operating system, powering future Web3 apps."}]},{"type":"paragraph","children":[{"text":""}]},{"type":"paragraph","children":[{"text":"Over time, the division will get clearer—and more invisible. Regular users won’t know (or need to know) whether they’re on L0, L1, or L2—just like you don’t worry about TCP/IP, HTTP, or WebSocket when you browse. Users will judge only speed, safety, and experience while the multi-layer stack hums quietly in the background."}]},{"type":"paragraph","children":[{"text":""}]},{"type":"paragraph","children":[{"text":"This trend also hinges on interoperability. As apps diversify, no single chain can do it all. Communication and bridging between L1s and L2s becomes essential. Cosmos IBC, Polkadot’s relay chain, and newer bridging tech all aim to dissolve blockchain island effects, enabling a truly interconnected metaverse and DeFi landscape."}]},{"type":"paragraph","children":[{"text":""}]},{"type":"paragraph","children":[{"text":"Another direction is “invisible blockchain” UX at the app layer. The end goal of modular layering isn’t to make users study the plumbing, but to make blockchains feel natural. Tomorrow’s users might just know they’re playing a game or paying with a wallet—without realizing the backend is a rollup or L0 messaging protocol. That’s the biggest value of the layered, modular approach: blockchain as unseen but reliable infrastructure."}]},{"type":"paragraph","children":[{"text":""}]},{"type":"paragraph","children":[{"text":"In three words: modular, cooperative, invisible. That’s how we tackle performance bottlenecks and reach meaningful scale."}]},{"type":"paragraph","children":[{"text":""}]},{"type":"paragraph","children":[{"text":"Conclusion","bold":true}]},{"type":"bulleted-list","children":[{"type":"list-item","children":[{"text":"The blockchain layered architecture is a master key for understanding crypto. From Layer 0’s foundation to Layer 1’s base chains, through Layer 2’s scaling, and into the application layer’s liveliness—each layer shapes tomorrow’s digital civilization."}]},{"type":"list-item","children":[{"text":"Today’s explainer might be tomorrow’s common sense—just like TCP/IP once felt esoteric but is now everywhere."}]},{"type":"paragraph","children":[{"text":"\n\n"},{"type":"topic","character":"cryptocurrency","children":[{"text":""}]},{"text":" "},{"type":"topic","character":"blockchain","children":[{"text":""}]},{"text":" "},{"type":"topic","character":"juExchange","children":[{"text":""}]},{"text":" "}]}]}]