What POL is
Polygon is a multi-chain Ethereum scaling ecosystem. The original Polygon PoS chain (launched 2020) is a sidechain with EVM compatibility and low fees, secured by its own validator set rather than Ethereum directly. The AggLayer is a coordination layer connecting Polygon chains with each other and with external chains, and Katana, a DeFi chain incubated by Polygon Labs and GSR, launched on it in 2025. POL is the network's native token, replacing the older MATIC token via a 1:1 migration.
Polygon zkEVM, the project's ZK rollup, is gone. Polygon announced in June 2025 that it would sunset zkEVM Mainnet Beta after years of low usage, gave users a 12-month window, and the sequencer stopped producing blocks in early July 2026. A claims interface for funds left behind stays open through December 31, 2027.
How it works
Polygon PoS uses a Heimdall + Bor architecture: validators stake POL, propose blocks on Bor (the EVM execution layer), and finalize them through Heimdall (Tendermint-based). The Rio upgrade, live since October 8, 2025, reworked block production so a small set of producers builds blocks while other validators verify them, targeting about 5,000 transactions per second with fast finality and no reorgs. The AggLayer aims to provide unified liquidity and atomic cross-chain transactions between participating chains.
Use cases
Polygon PoS hosts a large DeFi and NFT ecosystem (Aave, Uniswap, OpenSea collections), and significant stablecoin supply. It is widely used by enterprise integrations (Starbucks, Reddit, Nike) due to low fees and EVM compatibility. Since 2025 Polygon has leaned hard into payments: stablecoin transfers, payroll, remittances and merchant settlement on the PoS chain, which Rio was built to serve. The CDK (Chain Development Kit) lets projects launch their own chains connected through the AggLayer.
Tradeoffs and criticism
Polygon PoS is technically a sidechain secured by its own validators, not a rollup that inherits Ethereum's security, and with zkEVM shut down it is now Polygon's main chain. Retiring zkEVM also left users with funds in DeFi positions that could not be migrated automatically. The MATIC-to-POL migration confused some users, and some data providers still list the old ticker.