Update: BTC/NIM Swap

Dear Nimiq Community,

we know that you are joyfully anticipating the BTC support and of course the crypto-to-crypto swaps directly in our Nimiq Wallet.

We initially anticipated this set of new and exciting features to be released in the third quarter of this year and we are aware that you’ve been patiently awaiting the release. As you might have noticed, the swap is already live in the Nimiq Testnet Wallet and ready for you to try out!

The mainnet release is already very close. As with any new solution that is very complex underneath the hood, before entering the mainnet we need to make extra sure it is really release-ready not only from a security point of view, but also by having worked out less predictable usability kinks which is in everybodies interest!

Here a quick overview of the very last bits and pieces that we’re currently finalizing in order to move the swaps from testnet to mainnet:

  • We are currently working on integrating a smart animation that will give the swap a very natural and unique look and feel to both experienced users but also and especially to crypto newcomers. Imagine if you just found out about crypto and know nothing about atomic swaps and their uniquely valuable, non-custodial nature. What would you expect them to look and feel like in order to be perceived as something fun, innovative and appealing to use? Here’s a sneak peek for you: https://drive.google.com/file/d/1nK43Ot_Rzw9X1LfgyJodslhDipoJHu4Z/view?usp=sharing

  • The team is still working on the very last tasks related to the mainnet Fastspot API which is powering the complex atomic swap experience behind the crypto-to-crypto swap. While we are finishing our work on the API, please take a look at the brand new Fastspot Website in the meantime: https://fastspot.io

  • Before releasing the BTC integration and swaps we have to test the Bitcoin integration and BTC swap in the mainnet environment one last time. It is important to understand that this very easy-to-use-solution requires a lot of tech in the back in order to enable this smooth and pleasant non-custodial swap experience. We want and have to make sure that there will be no surprises after launch, and this simply requires some more testing and code audit for BTC handling.

  • A tricky real world fact of using non-custodial atomic swaps with BTC is that at times of high BTC network fees, these fees eat up a portion of the swap value (loading and unloading the HTLC effectively sums up to two BTC transactions). The UI needs to better and dynamically accommodate for that so that users are not surprised and to make clear that it is not Fastspot taking any odd cut.

As stated, we are very close to mainnet release and we are working hard through these last motions and appreciate your patience and excitement for whats about to come.

Pura Vida!

Max for Team Nimiq


And what about Lighting Network using in case to lower BTC network fees?

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Very great job! guys! Can’t wait for this new feature!

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Also pondering for xDai as alternative route for Ethereum to cope with rising gas fees ahead of ETH 2.0 and Nimiq 2.0

Thank you for the update on the delays and the clear explanations. Really appreciate the communication on this.


The Fastspot site is fantastic. It gives users just enough information to catch their attention but not to discourage them. I like the UX very much.

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Fastspot website is looking great!

Just tried the NIM <-> BTC swap inside wallet. While the slider thing looks nice, I didn’t find it very practical, I was not able to select the exact amount I wanted to swap. I tried typing the amount in the input field, but it’s not editable.

Agree with you. I’m not a big fan of the swap interface in the wallet too. The slider looks fancy, but I can’t specify the exact amount to swap. Furthermore, I think it’s leaning too much on the side of simplicity and hides the crucial fact that there’s an exchange rate in the background. A user could easily swap his NIM to BTC by clicking the slider, not aware that it was using the market rate at that moment. A big warning should be given about this IMO, if we’re in a bear market, users could easily lose their money by sliding the sliders repeatedly without fully understanding what it means.

Curiosity got the better of me… please move to another thread if required.
Tried swapping NIM to BTC and worked fine. Two days ago, I started an atomic swap of BTC to NIM. It has been around 60 hours since and transaction has not completed or reverted, seems to be stuck. BTC is no longer in wallet and no NIM recieved back. The refund button doesnt seem to do anything.
I have screenshots of the Tx ID’s etc - if you could please point me in the right direction on how to solve this?
Many thanks!

Hi! Sorry to hear it got stuck for you.

Can you please share with me (in personal message if you like) the BTC address that your BTC got sent to, and your NIM address that you used in the swap? Then we can manually refund you the BTC or send you the NIM (which do you prefer)?

I am having the same problem as pipenetworks previously had. I submitted a purchase of nim from BTC and the BTC is gone and the NIM never showed up. In fact I got a error message the transaction was rejected by network rules… Any chance you could give me a helping hand as well?

Hi Shannon!
Sure, just send me the same info as I requested for the previous case.

Hello! Help me please. Recently ive tryed to swap USDC-NIM on my cellphone in nimiq wallet app, it failed several times, i gave up. Morning ive noticed that USDC was spend in my wallet, on creatong HTLC state , but NIMIQ wasnt received. so no USDC no NIMIQ , Refund button dont work - Fee to gigh error. Paymaster rejected in server . What can i do ?