Polygon's architecture has four components: the Ethereum layer, the security layer, the Polygon network layer, and the execution layer.
Polygon uses Ethereum as its base layer. This layer consists of a set of smart contracts on Ethereum that settles by validating nodes, staking nodes, and passing information between Polygon and the Ethereum ecosystem. This layer is responsible for solving the final processing flow on Ethereum. While this layer is optional, this component of the architecture is where Polygon excels. By leveraging Ethereum as an endpoint, Polygon can benefit from using Ethereum's security as the ultimate shield.
The second architectural layer is an optional security layer. This layer is called "Verification as a Service" because it allows developers to leverage several security solutions to verify transactions. Users can employ fraud proofs or PoS sidechains (among other solutions) for security.
By far the most popular security solution is PoS sidechains. The PoS sidechain utilizes a set of about 100 validating nodes to ensure the security of the blockchain project (a certain validation fee will be charged) and conduct validating node management. In addition, this layer can use Ethereum miners (final validators) to reach consensus.
Again, this layer is optional. In general, fabric layers farther from layer 1 tend to be less secure, but improve transaction throughput, as well as user experience. Not all chains need to utilize Polygon's security layer. Some projects, such as Chain Games, may even want to reduce security in exchange for faster settlement, allowing players to have a good user experience.
PPolygon network layer
The Polygon network layer is a network of independent blockchains that determine transactions, produce blocks, and determine the consensus of their respective chains. These chains can be independent chains or secure chains. The block producers of these chains group their respective transactions, and depending on the security solution, the network layer will issue a Merkle root as a checkpoint for the first layer.
Finally there is the execution layer. The execution layer interprets and executes transactions determined by the Polygon network layer.
This layer has two components.
Execution Environment – Implemented by a virtual machine. Similar to EVM, it can track the state of the blockchain.
Execution Logic - Implements state transitions for a specific Polygon blockchain. This logic is used to define transitions to the next blockchain state, and Ethereum can be thought of as an "infinite state machine". (As opposed to a finite state machine (English: finite-state machine, abbreviation: FSM), a finite state machine is often referred to as a state machine, which is a mathematical model that represents a finite number of states and behaviors such as transitions and actions between these states.)
However, in all of these layers, the key value-added point for developers is the security layer, as this allows the flexibility of the Polygon framework to really come into play. Developers can choose a security solution that suits their project, and can swap solutions if they choose to change direction. Its purpose is to provide developers with a set of tools for customizing blockchain projects.