1. Layer 1 Chains

These are base-level blockchains — they’re the foundation.
 Popular Layer 1s include:

• Bitcoin: The OG. Peer-to-peer digital cash.
  
  
• Ethereum: Smart contracts, DeFi, NFTs.
  
  
• Solana: High-speed, low fees, used for DeFi and NFTs.
  
  
• Cardano: Research-driven, eco-friendly, focuses on scalability.
  
  

📰 NEWS SNAPSHOT:
 As of this week, Ethereum’s Layer 1 is still facing congestion during high DeFi activity — driving the trend for Layer 2 solutions (next).

2. Layer 2 Chains

These sit on top of Layer 1s, helping them scale.
 They reduce transaction fees and speed things up.
 Examples:

• Polygon: Popular for cheaper Ethereum transactions.
  
  
• Arbitrum: Growing fast with DeFi protocols.
  
  
• Optimism: Similar to Arbitrum — making ETH cheaper & faster.
  
  

📰 NEWS TODAY:
 Polygon recently announced new partnerships to expand its zkEVM technology — a huge step in making Ethereum-based apps more efficient and cost-effective.

 3. Sidechains

A sidechain runs parallel to a main chain but can have different rules.
 Example: Polygon is technically a sidechain for Ethereum.

Sidechains offload work — freeing up the main chain.

 4. Private vs. Public Chains

• Public Chains: Anyone can join, like Bitcoin or Ethereum.
  
  
• Private Chains: Permissioned, for companies or governments.
  Example: Some banks build private chains for internal transactions.