Blockchain Layers 0,1,2,3 in a diagram
3 min read

Blockchain Layers 0,1,2,3 in a diagram

Both definitions of Layer 0 explained so we can all be less confused👇

This is a more comprehensive look at:

  1. The Blockchain layers
  2. Where they fit in with the current 'web 2' infrastructure
  3. De-bunk the confusion around what "layer 0" means

The entire web3 stack and where it fits in with web2

This diagram shows the web2 stack vs. web3 as well as the layers of hardware and infrastructure that sit beneath both web2 and web3 stacks.

Blockchain layers and web2 layers

If you omit web3, this is what the OSI model layers used to look like:

OSI model

Layer 0

Definition: Can be seen as a bridge between the blockchain, the internet, and the physical world.

Simplified 🙏 : Think of layers as clothing. Layer 1 is your T-shirt. It’s the ‘main chain' of your outfit. Layer 0 is your undershirt - it keeps you warm but no one sees it doing its job.

The confusion❓❓❓: You’ll hear and read two definitions of ‘layer 0’. Let’s take a look at where both renditions of layer 0 appear in the stack below:

Now that you can visualize what the layers look like and where they're located, we’ll dive into the 2 definitions you might have heard and make all of this less confusing ☝️

Layer 0 Definition #1:

The hardware and all-encompassing data connection layer  

Correct definition ✅

To be truly layer 0, it has to connect *both web3 and web2 data.

Example: Constellation Network

Pictured above in the center of the picture, Constellation, is trying to be the connectivity for all data between blockchains and web2 and the hardware that underpins it all.

Layer 0 Definition #2:

"The blockchain of blockchains"

Incorrect definition 🛑

“The blockchain of blockchains” would imply a world where everything that happens on-chain, happens within one ecosystem. An example is a scenario where everyone ditched eth, bitcoin, etc, and moved all their assets and transactions to Polkadot.

Which would make Polkadot the sole blockchain. In this case, Polkadot could be considered a “layer 0” specific to the blockchain world and all 'new chains' are built on top of the greater Polkadot ecosystem (called parachains). Even still, Polkadot would not be considered “layer 0” since it’s not connecting to the rest of the web.

Here is an example of the Cosmos ecosystem, which also markets itself as a “blockchain or blockchains”:

Examples: Polkadot, Cosmos.

These are more marketing schemes than anything else. Yes, there is interoperability and composability but still only within each of these ecosystems. There will always be use case-specific chains, which means there will always be siloed chains, which means these can’t be considered “layer 0”.

Even if we were referring to a world where only blockchains existed these "blockchain of blockchains" still can't be considered layer 0.

Layer 1

Layer 1s are blockchains (Bitcoin and Ethereum) that process and finalize transactions on their own blockchain. This is where things like consensus (PoW, PoS) and all the technical details like block time and dispute resolution take place.

The most important three aspects of blockchains are conquering the blockchain trilemma: decentralization, security, and scalability. Still no single blockchain has nailed all three.

Layer 1

Polkadot and Cosmos, marketing themselves as 'layer 0' above are shown correctly here as layer 1.

Layer 2

Layer 2s are third-party integrations used in conjunction with layer ones to increase scalability and transactions per second (system throughput).

When you hear zero-knowledge rollups (zk rollups), side chains, or anything to do with speeding up transaction throughput, it’s likely layer 2.

Layer 3

Layer 3 is the application layer. This is the UI that we as consumers actually interact with.