Fork of Polygon's fx-portal. Polygon's repo does not have an associated npm package so we forked it to create our own so that we can use the contracts without dealing with submodules.

fx-portal(Flexible portal)

FxPortal for Polygon(prev Matic)Chain. No mapping. Seamless communication with Ethereum Network.

What is Fx bridge (fx-portal)?

It is a powerful yet simple implementation Polygon state sync mechanism. Polygon PoS bridge is based on it. The code in the examples folder are examples of the usage of this methodology. You can use these examples to build your own implementations or own custom bridge.

In short, it's Meta bridge. This bridge allows any state-syncs without mapping.

Some use-cases of Fx-portal

• ERC20 token tranfer from Ethereum to Matic-Chain without mapping request
• Lazy minting of ERC20 tokens on MaticChain
• State Transfer between Ethereum-Matic

What about PoS portal?

PoS Portal is another bridge, but it works only for few ERC standards and requires mappings. It is more developer-friendly, allows customization without much headache.

While Fx-portal focuses on permissionless-ness and flexibility, a developer might have to write more code but more customizable than PoS Portal. It requires no mapping.

Can I build my bridge?

Yes. You can check docs here: https://docs.matic.network/docs/develop/l1-l2-communication/ethereum-to-matic https://docs.matic.network/docs/develop/l1-l2-communication/matic-to-ethereum

What are FxChild and FxRoot?

FxChild (FxChild.sol) and FxRoot (FxRoot.sol) are main contracts on which mapping-less bridge works. It calls and passes data to user-defined methods on another chain without mapping.

Mumbai

| Contract | Deployed address | | :----- | :- | | FxRoot (Goerli) | 0x3d1d3E34f7fB6D26245E6640E1c50710eFFf15bA | | FxChild (Mumbai) | 0xCf73231F28B7331BBe3124B907840A94851f9f11|

Mainnet

| Contract | Deployed address | | :----- | :- | | FxRoot (Ethereum Mainnet) | 0xfe5e5D361b2ad62c541bAb87C45a0B9B018389a2 | | FxChild (Matic Mainnnet) | 0x8397259c983751DAf40400790063935a11afa28a|

You can deploy your own FxChild and FxRoot, but no need. Except you want to have some fun and have extra ETH to throw away.

What can I build with it?

• Arbitrary state bridge (examples/state-transfer)
• Normal ERC20 bridge (examples/erc2-transfer)
• ERC20 token generator bridge (example/mintable-erc20-transfer)