Explaining WETH Conversion on Polygon Amoy Test Network

There is no native ETH on POS or Amoy networks; hence, the conversion to WETH occurs.

Hey, when you bridge using Polygon Portal from Sepolia ETH to Polygon Amoy, you receive WETH instead of ETH because on POS mainnet and Amoy, only the wrapped version of ETH exists.

TL;RD

Receiving WETH instead of ETH when bridging from Sepolia to Amoy is expected behavior. Since Polygon’s PoS network and testnets like Amoy do not support native ETH, the bridge automatically converts it to Wrapped ETH (WETH) upon arrival. This ensures compatibility with the ERC-20 token standard used on Polygon-based networks.

If you need native ETH, you can either bridge back to Sepolia, use a DEX to unwrap WETH, or interact with smart contracts designed for conversion. However, for most use cases on Amoy, WETH functions the same as ETH in DeFi, trading, and other blockchain applications.

Long Story

ETH is the native currency of Ethereum, meaning it exists as a base asset on Ethereum’s mainnet and testnets like Sepolia. When you use Ethereum, you can send ETH directly between wallets, pay for gas fees, and interact with smart contracts without needing any additional wrapping or conversion.

However, Polygon’s Proof-of-Stake (PoS) chain and its testnets, including Amoy, do not have native ETH. Instead, these networks use WETH (Wrapped ETH), which is an ERC-20 token that represents ETH but follows the ERC-20 token standard. This allows ETH to be used in smart contracts, decentralized applications (dApps), and DeFi protocols on Polygon’s network.

Because Amoy does not support native ETH, any ETH bridged from Sepolia must be converted into WETH upon arrival. This is why you received WETH instead of ETH when using the Polygon Portal bridge.

Why Is ETH Wrapped on Polygon and Amoy?

The main reason for using WETH instead of native ETH on Polygon’s PoS network and testnets like Amoy comes down to Ethereum’s token standards.

1. ETH Is Not an ERC-20 Token

   • On Ethereum, ETH exists as a base-layer asset, meaning it doesn’t follow the ERC-20 token standard used for most Ethereum-based tokens.
   • Since smart contracts and DeFi applications on Polygon expect ERC-20 tokens, ETH must be converted into WETH to maintain compatibility.

2. Polygon’s PoS Chain and Amoy Only Support ERC-20 ETH

   • Unlike Ethereum mainnet, where ETH is handled natively, Polygon and Amoy rely on an ERC-20 version of ETH.
   • Without a wrapped version, ETH would not be usable in DeFi protocols, swaps, lending platforms, or other dApps that require ERC-20 tokens.

3. Interoperability Between Chains

   • Wrapping ETH ensures that it can move smoothly between different networks and dApps, maintaining liquidity across ecosystems.
   • On Polygon’s PoS chain and testnets, WETH functions the same way as ETH but follows a standard that is easier to integrate.

How to Convert WETH to ETH on Amoy?

If you prefer to have native ETH instead of WETH, there are a few ways you can handle this:

1. Use a DEX to Unwrap WETH

   • Some decentralized exchanges (DEXs) allow you to unwrap WETH and receive ETH.
   • Look for an Amoy-compatible DEX that supports WETH-to-ETH conversion.

2. Bridge Back to Sepolia

   • If you bridge WETH from Amoy back to Sepolia, the process will reverse, unlocking your ETH on Sepolia and removing the WETH on Amoy.
   • This can be done through the Polygon Portal bridge or another cross-chain bridge that supports Sepolia and Amoy.

3. Use Smart Contracts to Convert WETH

   • On Ethereum, unwrapping WETH is done by interacting with the WETH contract and calling the withdraw() function, which converts WETH back to ETH.
   • If Amoy has a similar contract, you can do this manually via a blockchain explorer or a custom script.

When you bridge ETH from Sepolia to Amoy using Polygon Portal, you receive WETH (Wrapped ETH) instead of native ETH. This happens because Polygon’s PoS network and its testnets, including Amoy, do not support native ETH. Instead, they use WETH, an ERC-20 token that represents ETH but follows the standard needed for smart contracts and DeFi applications.

On Ethereum, ETH exists as a base asset, meaning it can be sent directly between wallets and used for gas fees. However, Polygon’s PoS chain and Amoy only support ERC-20 ETH, so when ETH is bridged, it is automatically converted into WETH for compatibility.

The bridging process involves:

• Locking ETH on Sepolia – The ETH you send is held in a smart contract.
• Minting WETH on Amoy – Since native ETH is unavailable, WETH is created at a 1:1 ratio and sent to your wallet.

WETH can be used like ETH for transactions, smart contracts, and DeFi, but it cannot be used for gas fees—you need MATIC for that on Amoy. If you want to convert WETH back to ETH, you can use a DEX (decentralized exchange) or bridge it back to Sepolia.