ICO contracts are meant to accept Ether as payin for the tokens sold, for example https://cartaxi.io/pre-ico or https://www.herocoin.io/

But there are a lot of ICOs running on Ethereum that accept BTC and even fiat money. For example, https://blackmooncrypto.com/ accepts BTC, ETH and LTC. How is that possible?

The ICO contract payable endpoint that delivers tokens accepts only Ethers. If an investor wants to buy tokens using Bitcoins, must he first exchange them into Ethers? Or is the very ICO organizer who performs the exchange task?

Is BTC Relay http://btcrelay.org/ a reliable, advisable solution to this problem?

Same question for fiat? Thx!


  • 4
    Just wanted to say this is a good version of similar questions that shows that research and thought went into it before posting (like the questions you linked to) :) Were it that more questions were like this!
    – lungj
    Sep 12, 2017 at 16:33

1 Answer 1


Yes, ethereum smart contract can only accept ether. So if one wants to use Bitcoin to buy ethereum tokens, then you need to do something to let it happen.

I have seen different approaches to this problem:

  • Some companies do the conversion for you - they show you a special BTC address where you can transfer your bitcoins to and the company will issue ethereum token for you. They need to know your ethereum address in order to issue tokens to it.
  • The other way is to exchange your BTC to ETH yourself using some external exchange website. This is something you need to do by yourself and then come back to ethereum and send ETH to smart contract directly.
  • Some just accept other currencies with no relation to ETH smart contract. You need to read the white paper and ask questions to support about how exactly they handle other currencies.
  • In the first option, tokens will be transferred manually?
    – Aniket
    Sep 18, 2017 at 21:31
  • It can be both ways. For example bitair.io will let you transfer BTC to a special address and then they will issue tokens to your ETH wallet (you have to set it in the dashboard on their website). tokenstars.com has similar dashboard - one can trasfer money to them, while the real token will be issued later and be delivered to your ethereum wallet. Untill you specify your ethereum wallet, tokens cannot be transfered to you. Sep 19, 2017 at 3:51

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.