I want to use MetaMask swap function automatically with code, but MetaMask don't provide ABI, then I have to use contract input data information to write swap function code, but I don't know the structure of input data for swap function, is there anyone who have done it? Please try to provide some help. Thanks!

  • I'd recommend to start reading about AMM, for example uniswap provides an SDK for using their services docs.uniswap.org/sdk/introduction. Similar products are Pancakeswap, 1inch, etc.
    – Ismael
    Commented Nov 9, 2022 at 6:39

1 Answer 1


Metamask won't provide anything, other than a good interface (UI) for quick and easy transaction inspecting and approval. you will need to create all the logic behind your swaps on your own. The only thing that you need to connect your code logic to metamask is window.ethereum

  • First you need to create a provider with the window.ethereum that metamask provides
  • Second you need to get the ABI, the best place will be etherscan or bscscan
  • Create the contract from the abi and the actual address you are trying to contact, here how to do it in JS : `web3.eth.Contract(<ABI_in_json_fromat>, )
  • Do the same for the token contract you want to swap, and call the approval method tokenContract.methods.approve(<address_of_the_swap_contract>, <amount_you_want_to_swap>)
  • finally you can execute the swap like follows : RouterContract.methods.swapExactTokensForTokens(<amount_in>, <minimum_amount_out>, <path>, <to_address>, <real_dead_line>)
  • Thanks for your answer. It seems that I can't swap with Metamask function interface. Is there any method that I could leave traces of the transaction on Metamask contract?
    – Jeff
    Commented Nov 7, 2022 at 11:57

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