[ANN] whales.exchange - FOSS web interface for Electrum Swaps built on Boltz

[bitdude]

Whale's Exchange is live now!

We have just released the first public beta version of Whale's Exchange. Please come test it, break things, and help us improve!

TLDR: Web interface for reverse swaps (LN→BTC) with Electrum Swap providers. You have bitcoin in a Lightning channel, you can swap for on-chain bitcoin.


Note that this is currently beta software, expect errors. This first public release only supports reverse swaps. Only use amounts you’re fully okay to lose.

About

Whale's Exchange is an open-source non-custodial Electrum Swap interface based on Boltz Exchange frontend. To understand what Whale's Exchange is, it is important to understand what submarine swaps are and also understand the two projects that it is built on.
Submarine Swaps

Submarine Swaps

Submarine swaps are a type of atomic swap that allows users to exchange on-chain bitcoin with off-chain bitcoin and vice-versa. Lightning Network users may sometimes have too little or too much liquidity in their channels, and submarine swaps allow them to swap between on-chain and off-chain bitcoin without trusting a third party custodian.

A Forward Swap (BTC→LN) is a swap where the user swaps on-chain bitcoin (BTC) for off-chain bitcoin (LN).

A Reverse Swap (LN→BTC) is a swap where the user swaps off-chain bitcoin (LN) for on-chain bitcoin (BTC). In the first version of Whale's Exchange, only the reverse swaps are supported.

Boltz Exchange

Boltz Exchange pioneered the concept of atomic swaps on Bitcoin with simple to use interface. It evolved into a web service that allows users to swap between various digital assets, not just Bitcoin, on different layers and chains.
Electrum Wallet

Electrum is a popular Bitcoin wallet that has been around since 2011. It is a feature rich wallet and often among first ones to implement new Bitcoin features.

Electrum Swap is a protocol that pushes the concept of atomic swaps on Bitcoin to the next level by decentralizing the swap process and allowing anyone to run a swap server. It leverages Nostr that is used by the swap providers to publish their swap offers and to arrange swaps with the clients.
Whale's Exchange

Whale's Exchange combines Boltz Exchange web interface with Electrum Swap. It allows participating in Electrum swaps without needing to run Electrum wallet. This allows expanding the user base of Electrum Swap ecosystem to more users.

While the web interface and the background API bridge are obviously centralized, the swaps themselves preserve the trust-minimized character that is inherent to Electrum Swap protocol. Whale's Exchange never gains access to user funds, and users retain full control of their bitcoin throughout the entire flow of a swap.

Of course, the user always needs to trust the interface they are using, whether it is Whale's Exchange web interface or whether it is Electrum Wallet. Electrum Wallet is a much more mature project that has been around for more than a decade, and it has a solid reputation. Whale's Exchange is a new project that still needs to build its reputation and trust among its users. To achieve that, all parts of Whale's Exchange are open source, and we encourage everyone to review the code and verify that it does what it is supposed to do; or even better, to run your own instance of Whale's Exchange, locally or on your own domain with your own branding.

Therefore, we can say that Whale's Exchange is somewhere in between Electrum Wallet and Boltz Exchange in terms of how much trust you have to put into it as a user.

Whale's Exchange does not receive any fees from the swaps as it does not participate in the swaps at all. It only facilitates communication between the user and the swap providers.

Resources

• Whale's Exchange Web App - the frontend interface
• Whale's Exchange Backend - API bridge to Electrum backend RPC in .NET
• Whale's Exchange Electrum Swap Bridge - modified Electrum wallet used to communicate with Electrum Swap providers

[dkbit98]

I don't understand what is the point of this exchange when there is exact same function already on Boltz exchange website?
In fact I compared exchanging 0.1 BTC to LN on both websites and I got significantly better rates on Boltz exchange.
I understand that I can choose different providers on your service, but I am always getting worse rates:



vs

[Zwei]

I don't understand what is the point of this exchange when there is exact same function already on Boltz exchange website?
In fact I compared exchanging 0.1 BTC to LN on both websites and I got significantly better rates on Boltz exchange.
I understand that I can choose different providers on your service, but I am always getting worse rates:



vs

i tought the same at first, but i see there is a different fee for LN to bitcoin and bitcoin to LN, which is why you are getting a worse rate comparing the two.
if you check some of the swap providers they actually have same or lower fees than boltz:



OP, when do you expect to support forward swaps?

[dkbit98]

i tought the same at first, but i see there is a different fee for LN to bitcoin and bitcoin to LN, which is why you are getting a worse rate comparing the two.
if you check some of the swap providers they actually have same or lower fees than boltz

Yeah you are right, but they have more centralization with no forward swaps, and on Boltz.exchange there are other options available like Liquid assets.
That being said, I understand whale.exchange is still in beta, and it's good to have more options available.

[bitdude]

I don't understand what is the point of this exchange when there is exact same function already on Boltz exchange website?
In fact I compared exchanging 0.1 BTC to LN on both websites and I got significantly better rates on Boltz exchange.
I understand that I can choose different providers on your service, but I am always getting worse rates:

Hi, couple of comments here

1) fees - you can check on Boltz exchange, they currently have different fees for forward and reverse swaps.

For forward swaps, they charge 0.1% + fixed network fee, which is very good indeed and currently, no Electrum Swap provider offers that. Our interface currently does not support Forward swaps, but we are working on it.

For reverse swaps, however, they charge 0.5% + fixed network fee and this is something that some Electrum Swap providers beat - currently I can see offers ranging 0.39% - 0.69%.

2) What is the point if it is exact same function ...?

So the point here is that it is not exact same function. On some level, yes, the idea is the same - to swap on-chain for off-chain and vice versa. But the distinction is a bit like CEX vs DEX. What Boltz is is an atomic swap service that is centralized in the service provider.

Electrum Swap is a protocol that anyone can join as a service provider. Our exchange is a mere interface to Electrum Swap and technical people can run our interface at home and it will still work because it connects to Electrum Swap world via Nostr. The original interface to Electrum Swap world is obviously Electrum Wallet, so our interface is just another interface for people who do not use Electrum Wallet.

So the point here is ideological. Some people don't mind CEXes, and that's fine, no problem with that as long as they are aware of the trade-offs. Notable difference here of course is that Boltz is non-KYC by itself and it is also by ifself non-custodial, so although if it operates the swap somewhat centrally, the CEX-DEX analogy is not perfect here as the usual main problems with CEXes are KYC and being custodial. So Boltz itself is pretty good already. Electrum Swap just takes it to the next level, but it is rather nuanced distinction that perhaps not everyone can appreciate.

[bitdude]

OP, when do you expect to support forward swaps?

Hi, we are working on it. There are specific challenges for forward swaps (discussed here https://github.com/spesmilo/electrum/issues/10611). There is no ETA at the moment, and we will need cooperation from Electrum Wallet guys to make this happen with full power. This is fully open-source, so any help is highly appreciated and interested parties can join our effort in the public repos of the project.

That being said, it should be noted that currently Electrum Swap protocol does not support asymmetric fee model. However, Electrum Wallet devs expressed interest in implementing that. Currently, it means that even if we had Forward swap support, the providers would not be able to offer better fees than Boltz on that unless they provided the same fee for reverse. But I believe Electrum Swap will evolve and will support asymmetric fees in the future, so then Electrum Swap will potentially offer competitive fees for both directions.

[bitdude]

i tought the same at first, but i see there is a different fee for LN to bitcoin and bitcoin to LN, which is why you are getting a worse rate comparing the two.
if you check some of the swap providers they actually have same or lower fees than boltz

Yeah you are right, but they have more centralization with no forward swaps, and on Boltz.exchange there are other options available like Liquid assets.
That being said, I understand whale.exchange is still in beta, and it's good to have more options available.

I'd say whales.exchange rather has less centralization than Boltz. That's kind of the whole point of Electrum Swap protocol - that the swaps are decentralized as opposed to Boltz model.

But yes, Electrum Swap is Bitcoin only (and whales.exchange is just an interface to it), so no USDT, no Liquid, no Rootstock.