Polygon

Polygon is an Ethereum scaling ecosystem with PoS checkpoints and POL gas

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Polygon is an Ethereum-compatible network that processes transactions on its own chain and anchors summaries to Ethereum, with proof-of-stake (PoS) validators staking POL and users paying POL fees. The broader ecosystem also includes Polygon CDK and Agglayer, while a wallet on chain ID 137 reaches the production network long known as Polygon PoS.

Key takeaway: A Polygon mainnet transaction needs a priority fee of at least 25 gwei, with its final POL cost set by gas consumed.

Choosing Polygon Chain for low-cost smart contract activity

The production network known as Polygon Chain, still widely called Polygon PoS, fits activity that needs Ethereum Virtual Machine (EVM) compatibility, frequent settlement, and a native POL balance for gas.

Related details are covered in Working with polygon. Choose it when the application and assets already exist on chain ID 137, the team accepts a separate validator set, and transactions benefit from lower execution cost than Ethereum mainnet. EVM compatibility keeps Solidity contracts and familiar tools such as MetaMask, Hardhat, Foundry, and ethers usable, although deployed addresses and liquidity remain chain-specific. Payments, games, marketplaces, and repeated decentralized finance (DeFi) actions gain from cheap blockspace. High-value settlement belongs on Ethereum or a rollup when the required security model demands Ethereum data availability or rollup proofs. The deciding inputs are application support, bridge path, gas token, and finality policy.

Network configuration identifies the ledger: the mainnet uses chain ID 137 and charges POL, while Amoy uses chain ID 80002 for testing.

Does Polygon Chain use the same model as Arbitrum One and Base?

Polygon Chain uses a different model from Arbitrum One and Base: its proof-of-stake validator set finalizes blocks, then submits checkpoints to Ethereum without a rollup proof system. Ethereum mainnet uses chain ID 1 and ETH gas; the PoS mainnet uses 137 and POL. Security assumptions, withdrawal mechanics, application liquidity, and gas-token preference settle the choice among this network, Arbitrum One at 42161, OP Mainnet at 10, and Base at 8453.

Bor execution, Heimdall milestones, and Ethereum checkpoints

Execution and consensus are separated on Polygon Chain: Bor runs EVM transactions and produces blocks, while Heimdall-v2 selects producers, finalizes milestones, and coordinates Ethereum checkpoints.

Block production after Rio

Bor is based on Go Ethereum, with Erigon also supported. Post-Rio, exactly one elected producer seals every block in a span; a producer pool holds up to four eligible candidates. Each sprint contains 16 Bor blocks, and each span contains 400 sprints, so one span covers 6,400 blocks. If production stalls, Heimdall rotates the span rather than relying on an out-of-turn backup.

Milestone finality

Heimdall-v2 runs on forks of Cosmos SDK and CometBFT and uses validator vote extensions to agree on the longest common run of Bor block hashes. Heimdall milestones finalize Bor blocks when at least two-thirds of validating stake agrees, normally within 2 to 5 seconds. The finalized block tag in the standard eth_getBlockByNumber JSON-RPC call exposes this state to wallets and applications. Milestone finality governs activity staying on the chain; it does not wait for an Ethereum checkpoint.

Checkpoint anchoring

A checkpoint packages a contiguous range of Bor block hashes into a Merkle root and records it in Ethereum contracts. Its interval is governance-set, so a wallet transfer can reach milestone finality before its range appears on Ethereum. Checkpoint inclusion matters for Polygon-to-Ethereum withdrawals because the exit contract verifies the burn proof against the submitted root. It also explains why bridge completion is slower than an ordinary on-chain transfer.

The chain therefore has two relevant clocks: milestone finality for ordinary activity and a longer, variable wait for Ethereum checkpoint inclusion. For an on-chain payment, the applicable endpoint is the finalized milestone, normally reached within 2 to 5 seconds.

Polygon graphic reading The go-to blockchain for payments
Polygon graphic reading The go-to blockchain for payments

What does POL pay for?

POL pays Polygon Chain transaction fees and underpins validator staking, while its Ethereum ERC-20 form supports the MATIC migration and delegation contracts.

Transaction fees

The network follows EIP-1559 Type 2 pricing: gas used is multiplied by the base fee plus the effective priority fee. The base portion is burned, and the priority portion goes to the block producer. Mainnet enforces a minimum priority fee of 25 gwei; one gwei equals 10^-9 POL, while one wei equals 10^-18 POL. A plain native transfer uses 21,000 gas before any contract execution, so token swaps, approvals, and non-fungible token (NFT) mints consume more. Wallet estimates should set both maxFeePerGas and maxPriorityFeePerGas rather than copying a stale total.

Validator staking

Validators stake POL through Ethereum contracts, not on Polygon Chain itself. Entry as a validator requires at least 10,000 POL, and the active set supports up to 105 validators. Delegators can start with 1 POL, while unbonding locks principal for 80 checkpoints. Because staking transactions execute on Ethereum, they also need ETH for Ethereum gas; local gas prices do not determine those costs.

Migration and supply

MATIC on Polygon Chain converted automatically into POL at a 1:1 ratio; MATIC held on Ethereum uses the migration contract. POL began with 10 billion tokens and follows an emissions schedule rather than retaining MATIC’s original fixed ceiling. The published schedule establishes an effective 2% annual issuance after June 2025, split into 1% for validator rewards and 1% for the community treasury, while governance can alter the emission manager within the token contract’s cap. That governance path makes future supply an explicit protocol variable.

Payments, DeFi, and digital assets

Applications on Polygon Chain that repeat small EVM state changes include stablecoin payments, exchange transactions, lending positions, prediction markets, game items, and tokenized assets. USDC provides a payment denomination; Aave and Uniswap supply DeFi venues; Polymarket uses the network for market activity; and ERC-721 or ERC-1155 contracts represent individual or multi-token assets. Each action settles on the mainnet at chain ID 137.

A clean first transaction on chain ID 137

A first Polygon transaction needs an EVM wallet, the correct network, enough POL for gas, and an asset route ending on chain ID 137.

Wallet and network

MetaMask, Rabby, and WalletConnect-compatible apps use the same 20-byte EVM address format seen on Ethereum. Add the mainnet with chain ID 137, or choose Amoy at chain ID 80002 when testing. Network selection changes the ledger a wallet reads; it does not create a new private key. An address may therefore look identical across chains while holding different balances.

Funding and asset identity

Acquire a small POL balance on the destination chain before submitting a normal transaction. Assets arriving from Ethereum through Polygon Portal are locked on Ethereum and represented 1:1 on Polygon; returning them reverses that mint-and-lock flow. A centralized withdrawal must also select Polygon as the network. Match the displayed token contract to the intended representation because identical symbols do not establish identical contracts.

Network decision checklist

After signing, retain the 32-byte transaction hash. PolygonScan or an RPC receipt shows inclusion, while the finalized block tag distinguishes inclusion from deterministic finality. That record is the clean handoff point for an exchange, merchant, or application.

From Matic Network to POL: the trade-offs that remain

In the common configuration, Polygon evolved from Matic Network into a broader scaling ecosystem, but Polygon Chain still carries a distinct validator, bridge, token, and governance model.

The security boundary spans two clients, Bor and Heimdall-v2, plus staking and bridge contracts on Ethereum. Up to 105 active validators participate, yet one elected producer orders every block inside a 6400-block span; Heimdall milestone voting supplies the two-thirds finality threshold. This design lowers coordination overhead, while temporary producer concentration and span rotation become relevant failure modes during a stall. Ethereum checkpoints strengthen anchoring and enable exits, but they do not make each transaction inherit Ethereum’s rollup data or proof model. Users therefore assess validator operations, bridge contracts, and asset liquidity together.

The 2021 rebrand broadened Matic Network beyond one chain, and the 1:1 MATIC-to-POL migration later changed the gas and staking unit without changing native balances. Polygon CDK builds separate chains, while Agglayer coordinates cross-chain interoperability. Neither changes the wallet rules of the mainnet at chain ID 137.

Polygon - your questions answered

Does Polygon support Ethereum smart contracts without code changes?

Polygon Chain supports Ethereum smart contracts through EVM compatibility. Solidity contracts and standard tooling transfer with little protocol-level change, but deployment creates a separate address and state on chain ID 137. Integrations must select Polygon-specific tokens, oracles, liquidity, and RPC configuration. Hardhat or Foundry can deploy the code, while ethers, MetaMask, and WalletConnect connect users to applications.

How long does a Polygon-to-Ethereum withdrawal take?

A Polygon-to-Ethereum withdrawal takes longer than a transaction staying on Polygon because the exit waits for checkpoint inclusion and then an Ethereum transaction. Milestone finality in 2 to 5 seconds does not complete that bridge path. Checkpoint timing is governed by protocol parameters and Ethereum conditions, so no fixed wall-clock promise applies; the receipt becomes claimable only after its Bor block range is checkpointed and accepted by the Ethereum exit contract.

Which token standards does Polygon Portal support?

Polygon Portal handles mapped assets through bridge contracts for ERC-20 fungible tokens, ERC-721 non-fungible tokens, and ERC-1155 multi-token collections. A token must have the correct root-and-child mapping before the canonical bridge recognizes it. Deposits lock the Ethereum representation and mint the mapped Polygon representation 1:1; exits burn the child representation before releasing the Ethereum asset at settlement.

Is MATIC still usable after the POL migration?

MATIC was superseded by POL as Polygon Chain’s native gas and staking token. Balances held natively on Polygon converted automatically at a 1:1 ratio, while Ethereum-held MATIC uses the migration contract for conversion. Some wallets may still display the old symbol until their network metadata changes. Stakers and delegators receive rewards in POL, and applications should label the native currency as POL on chain ID 137 for accurate gas estimates.

Do I need ETH to delegate POL?

ETH is required to pay for delegation transactions because Polygon staking contracts operate on Ethereum mainnet. The delegated asset is POL, but approval, delegation, reward, and unbonding actions consume Ethereum gas rather than Polygon gas. Holding POL only on chain ID 137 does not fund those calls; the staking address needs POL and enough ETH for each transaction.

What happens if a Polygon transaction runs out of gas?

A Polygon transaction that exhausts its gas limit reverts its state changes, while the gas already consumed remains charged. The receipt records a failed status, and the sender’s nonce advances because the transaction was included. Resubmitting requires a new transaction with the next nonce and a sufficient gas limit. Raising only the priority fee changes inclusion incentives; it does not increase the computation the transaction is allowed to use on the next attempt.

Can the POL supply increase beyond 10 billion?

POL supply can increase beyond its 10 billion initial amount under the token’s emissions design. The published schedule establishes ongoing issuance for validator rewards and the community treasury rather than preserving POL’s original fixed ceiling. Governance can modify the emission manager within contract constraints, so future supply depends on protocol decisions as well as scheduled minting, not on transaction-fee burning alone.

Will the same wallet address work on Ethereum and Polygon?

The same EVM account address works on Ethereum and Polygon because both derive the address from the same private key. Balances and contract state remain separate on each chain, even though the 20-byte address looks identical. A wallet must switch to chain ID 137 to read Polygon assets and submit Polygon transactions. Exchange withdrawals and bridge transfers must also name Polygon as the destination network before the account receives the intended asset representation.