Layer 1: The Base Blockchain
What makes a chain a 'Layer 1', and why everything else settles back to it.
What 'Layer 1' means
Layer 1 just means the base blockchain itself - the network with its own validators, its own consensus rules, and its own native token. Bitcoin is a Layer 1. Ethereum is a Layer 1. So are Solana, Avalanche, and dozens of others.
When people call something 'a blockchain' with no other qualifier, they usually mean a Layer 1: a self-contained system that doesn't depend on any other chain to function.
One layer, four jobs
A Layer 1 bundles together everything a blockchain needs to do on its own: it orders and executes transactions, reaches consensus on the result, publishes the underlying data so anyone can check it, and settles - makes the outcome final and irreversible.
Because one network handles all four jobs itself, a transaction confirmed on a Layer 1 doesn't need any other chain to vouch for it. That self-sufficiency is exactly what later lets other systems borrow its security, which is where Layer 2s come in.
Trade-offs baked into the base layer
Every Layer 1 makes choices. More validators and stricter hardware-independence tend to mean stronger decentralization and security - but also a lower ceiling on how many transactions the network can process per second.
A chain can loosen those constraints to go faster, but it's spending some decentralization or security to get there. There's no free lunch at the base layer - which is exactly the tension the next lesson names directly.
Remember
No single Layer 1 has 'solved' this trade-off - different chains simply choose different points on the spectrum.
Self-check
Check your understanding
Try each question before opening the answer.
What best describes a 'Layer 1' blockchain?
- A.Any app built with smart contracts
- B.A self-contained base blockchain with its own consensus and validators
- C.A wallet that supports multiple chains
- D.A chain that only exists to speed up another chain
Reveal answer
B. A self-contained base blockchain with its own consensus and validators
Layer 1s are the base networks - like Bitcoin or Ethereum - with their own consensus, validators, and native token.
Which of these is NOT something a Layer 1 handles on its own?
- A.Ordering and executing transactions
- B.Reaching consensus on the result
- C.Publishing the underlying transaction data
- D.Nothing - a Layer 1 handles all of these itself
Reveal answer
D. Nothing - a Layer 1 handles all of these itself
A Layer 1 is self-sufficient: it executes, reaches consensus, publishes data, and settles finality without relying on another chain.
Why doesn't any single Layer 1 maximize decentralization, security, and speed all at once?
- A.It's a marketing choice, not a technical one
- B.Pushing throughput higher tends to trade off against decentralization or security
- C.Only Bitcoin has this limitation
- D.Regulations prevent it
Reveal answer
B. Pushing throughput higher tends to trade off against decentralization or security
Base-layer design involves real trade-offs - this tension is formalized as the blockchain trilemma in the next lesson.
Continue this track