FCL Cross-VM Packages

These packages enable you to leverage Flow’s Cadence-Owned Account (COA) within Ethereum tooling (e.g., Wagmi, RainbowKit). They provide a unified approach for cross-VM apps on Flow and EVM, letting you perform EVM-like operations using Cadence accounts.

For background and motivation, see the FCL Ethereum Provider for Cross-VM Apps FLIP #316.

Package	Purpose
@onflow/fcl-ethereum-provider	Provides an EIP-1193-compliant Ethereum provider backed by an FCL-authenticated COA.
@onflow/fcl-wagmi-adapter	Integrates Flow-based COAs with Wagmi, exposing them as Ethereum accounts in your dApp.
@onflow/fcl-rainbowkit-adapter	Enables a Flow-based wallet option in your RainbowKit wallet selection modal.

@onflow/fcl-ethereum-provider

• Description: A drop-in EIP-1193 provider that authenticates users via FCL and lets them sign transactions/messages with their COA.
• Use Cases:
  • Integrate Flow EVM with any generic EVM library or framework.
  • Direct control over JSON-RPC calls (e.g., provider.request({ method: 'eth_sendTransaction' })).
• Link to Docs: Read the @onflow/fcl-ethereum-provider Reference »

@onflow/fcl-wagmi-adapter

• Description: A Wagmi connector that uses @onflow/fcl-ethereum-provider under the hood so you can sign in with your COA through standard Wagmi flows.
• Use Cases:
  • Add Flow-based COAs to an existing Wagmi-powered dApp as if they were Ethereum wallets.
• Link to Docs: Read the @onflow/fcl-wagmi-adapter Reference »

@onflow/fcl-rainbowkit-adapter

• Description: A RainbowKit adapter that surfaces a Flow-based wallet in the wallet selection modal, making it easy to sign transactions via COAs in a RainbowKit environment.
• Use Cases:
  • Offer Flow-based wallets (e.g., Flow Wallet) alongside popular Ethereum wallets in RainbowKit.
• Link to Docs: Read the @onflow/fcl-rainbowkit-adapter Reference »