For our first edition of #Nostrversity, we'll be diving into Nostr Wallet Connect, or #NWC; a handy means of connecting a #Lightning wallet to your favorite #Nostr app that quickly became the standard and is now an essential part of onboarding to Nostr for any new user who wants to experience the magic of zaps. Yet NWC enables so much more than just one-tap-zapping, as we will see when we look a little closer at how it works under the hood.
Lightning History on Nostr
Back in the wild-west days of Nostr, before
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invented zaps, Bitcoin psychopaths were already sending sats to one another over Nostr. However, the way we had to do it back then was by going into our Lightning wallet, selecting "receive," inputting an amount we wanted, and copy/pasting an invoice from the wallet into our Nostr note, then hope someone was willing to pay it. And the payment side was just as cumbersome, requiring manually copying the invoice from your Nostr client, pasting it into a Lightning wallet so you could see how much the other user wanted, and then deciding if you were even willing to send it.It didn't take long before Nostr clients, particularly on mobile, started rendering Lightning invoices in a convenient format that showed the invoice amount and a "Pay" button, that would prompt the user to open a Lightning wallet. This took out a decent amount of friction for the sender, but it was still just as big a hassle for the receiver.
Then zaps came along, and soon everyone had the ability to send sats to any other user when they found value in the content they posted. At least, any other user that added their Lightning address to their profile and whose Lightning wallet provider supported sending a "paid" receipt to a Nostr relay. Receiver friction had been virtually eliminated and the sats began to flow. Nostr also became the de facto directory for Bitcoiner payment addresses. If you heard
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say something brilliant on a podcast, you could just look her up on any Nostr client with zaps and send some sats her way as a thank you.Enter the zapathon, a community event with one purpose: break
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by zapping each other so much it was effectively a DDOS attack. Sure, it was a stress test on other wallets too, but most users were on Wallet of Satoshi because it was the easiest way to get a Lightning address with a mobile wallet.It was a ton of fun flinging sats around as fast as your fingers would let you! However, a new friction point was soon discovered from trying to zap so frequently. Every time you tapped the zap icon in your Nostr client, you had to wait for your wallet to open and present the invoice to approve payment, then switch back to your Nostr client to zap the next note. Not a big deal when you only send a zap occasionally, but when trying to zap every note in your feed, it adds a significant amount of time and extra clicks. In fact, this small amount of friction, whether you realize it or not, often acts as just enough of a barrier to zapping that you will choose not to zap a post you found some value in, just because of the extra 5 seconds it takes to load into your wallet app, approve the payment, and switch back to your Nostr client.
Wouldn't it be amazing if we could have one-tap-zaps?
I can't recall if there were any other methods by which this was achieved, but the method that caught on was developed and released into the wild by
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who called it Nostr Wallet Connect. At that time (March of 2023), Alby was a custodial Lightning wallet for your web browser, and while you could connect your own node to it using LNDHub, most people just stuck with their custodial option since it came with a Lightning address. Nostr Wallet Connect was, at that time, a way to connect your Alby wallet to a Nostr client.I am not certain which client was the first to support NWC, but I know that #Amethyst was pretty early on, and it was an instant success. Users could get a "connection string" from Alby, paste it into Amethyst, and zap with a single tap of their finger. Just like zaps themselves had eliminated the friction for receiving payments via Lightning for anyone with a Lightning address, Nostr Wallet Connect had eliminated the friction for sending payments. No more wasted seconds switching back and forth between Nostr client and wallet app, just tap and zap sent, tap again and another zap gone.
Of course, this meant that it was all too easy to send way more sats out of your wallet than you intended. This was solved by the ability to set budgets, so your wallet would cut you off once you reached the max amount you had set for yourself.
Because Alby had made Nostr Wallet Connect open source and part of the Nostr protocol, it didn't take long before more and more clients started adding support for it. Users demanded it and wouldn't shut up about it until it was added. Other wallet providers also saw the value of including it. Now it is simply expected, and any wallet that doesn't include it won't attract Nostr users.
Notably, Wallet of Satoshi went from being the most popular wallet among Nostr users to being a rare and quaint throwback to a bygone era, because they never integrated NWC and they pulled away from serving anyone in the U.S. out of fear of regulation under the Biden administration.
So we arrive at the state of Lightning on Nostr today, with Lightning addresses in our profiles for receiving zaps, and Nostr Wallet Connect for sending, and hard pressed to find Nostr clients that don't support both.
So... How does it work?
All of that history is great, but you're here to learn how this technology works. What is happening behind the scenes when you tap that little ⚡️ icon and sats seem to magically leave your Lightning wallet and show up on your screen as a zap underneath the latest
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meme, without you having to fiddle around with any Lightning invoices at all?It's really quite simple, in the end. Your wallet communicating with your Nostr client using a Nostr relay in the middle, the same way you communicate with other Nostr users by saving notes to a relay that they can retrieve them from.
First, your Nostr client has to know how to "tag" your wallet, and on which relay to send it notes. This is why you need to get a "connection string" from your wallet to paste into your Nostr client. This string has all the information that is needed for your Nostr client to know how to communicate with your wallet, and for your wallet to be sure that the payment requests are authorized by you.
Let's take a look at an example connection string:
nostr+walletconnect://b889ff5b1513b641e2a139f661a661364979c5beee91842f8f0ef42ab558e9d4?relay=wss%3A%2F%2Frelay.damus.io&secret=71a8c14c1407c113601079c4302dab36460f0ccd0ad506f1f2dc73b5100e4f3c Looks like a bunch of gobbledygook, right? We'll break down each of its parts and see what it does.
nostr+walletconnect:// This portion just defines the type of information that follows it. Because the string starts with this marker, any software reading it will know that what follows is information on how to communicate with a Lightning wallet, so long as it has been programmed to recognize it.
b889ff5b1513b641e2a139f661a661364979c5beee91842f8f0ef42ab558e9d4 This section is just a public key, the same as an In fact, it can be readily converted to an if you want using
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key converter. It's a nostr identity just like yours or mine, but you won't find any GM posts or catstr pictures in its note history. It's only posting special note types used by NWC. This public key belongs to your Lightning wallet, and just like you can have multiple for each of your alter egos, your wallet creates a separate public key to use with each new app you want to connect it to. Or at least it should. The Nostr client you use will tag your wallet in notes it creates by using this public key.relay=wss%3A%2F%2Frelay.damus.io This section is probably easily recognizable. It's the same as typing
relay=wss://relay.damus.io , except that it has to use %3A%2F%2F in place of :// . This tells your Nostr client which relay it needs to use to communicate with your wallet. Hopefully your wallet uses a relay with high up-time, because one of the major ways for NWC to fail is if the relay is down. You also can't use just any relay. It has to accept the note kinds used by NWC, which is why wallets don't typically let their users choose the relay that will be used. You also can't just modify the connection string to use a relay you prefer, even if you know it allows NWC note kinds. This is because it will result in your Nostr client sending requests to your wallet on that relay, but your wallet is not reading from that relay, so it will never receive the requests. secret=71a8c14c1407c113601079c4302dab36460f0ccd0ad506f1f2dc73b5100e4f3c This is just a Nostr private key. It's an nsec, but in hex format. Your wallet is giving your Nostr client a private key that it must use to sign all of the requests it sends to your wallet. No request signed by any other private key will be answered by your wallet. Your wallet will generate a separate private key for each connection string, allowing you as the user to revoke those connections individually, or set a separate budget for each connection.
When you tap the ⚡️ icon in your Nostr client, it obtains a Lightning invoice from the user's wallet you are trying to zap using their Lightning address. It then creates a note tagging your wallet's public key and requesting payment of that Lightning invoice, signing the note with the private key your wallet generated for it, and writing that note to the specified Nostr relay. Your wallet is constantly checking that relay for new notes and when it sees the payment request signed by an authorized private key, it pays the invoice, so long as it is within the budget you set, and sends out a payment receipt stating it has been paid so your client can light up the zap indicator to show that it was successful. All of this from a single tap of your finger in Amethyst.
More than Zaps
Now that we know the basics of how NWC works, it doesn't take much extrapolation to realize that this communication between wallet and Nostr client could be used for much more than just payment requests. A client could ask for your wallet's balance information, or transaction history, or ask for a lightning invoice. In fact, why does it have to be a Nostr client making those requests at all? Why not a mobile wallet app, or browser extension?
One of the major pieces of friction felt by those who run Lightning nodes is the difficulty of connecting to them remotely in a secure way.
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allow for connecting via Tor by default, but that can be painfully slow and unreliable. Anyone who has set up a connection to their node via LND Rest over Tor to theirnpub1xnf02f60r9v0e5kty33a404dm79zr7z2eepyrk5gsq3m7pwvsz2sazlpr5
wallet can attest to the frustration of opening their wallet and waiting several seconds for the interface to load, only to receive a timeout notice.Nostr Wallet Connect has eliminated this issue thanks to Alby Hub and Alby Go. Just create a new connection in Alby Hub, give it a budget, and scan the QR code with Alby Go and you have a fully-functional, mobile Lightning wallet connected to your node at home that loads extremely quickly and reliably, so long as the Nostr relay in-between is up and running.
Now, you may be concerned that the information being passed back and forth on this Nostr relay is incredibly sensitive financial information, especially if balance and transaction history is involved. However, this is not a concern because the content of the notes is fully encrypted. The relay owner, or anyone else with access to read data on that relay, has no idea what information is contained in the messages being sent between wallet provider and Nostr client, or Lightning node and mobile wallet. And because neither being used by your wallet provider or your Nostr client is the same as your there is nothing tying the messages to you.
As a result, NWC is quickly becoming an integral piece of Lightning infrastructure, even if those making use of it have no interest in joining Nostr at all.
The Future of NWC
To wrap this up, I'd like to point the reader to recent developments with Nostr Wallet Connect, and other use-cases we could very well see in the near future.
First, NWC may not just be for Lightning.
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recently revealed that he has a working prototype of on-chain payments via NWC.Loading note
We are already seeing it used with eCash wallets like
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There is no reason we shouldn't expect to see it used with all forms of Bitcoin payments. This could lead to an explosion of available wallet applications for all platforms, since they will simply be an interface for communicating with your node or wallet provider.NWC can also be used for subscriptions, as alluded to in
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note above. Before you protest about what an awful monetization model subscriptions are, I generally agree. That said, subscriptions where the user remains in control the entire time, and can unilaterally cancel the subscription at any time, without having to jump through hoops and give explanations about why they no longer want to use the service, is a massive improvement over the current status quo. Remember, NWC allows the user to set a budget for each connection. This means your subscription can't incrementally increase its monthly fee on you. Not without you willingly going into your wallet settings and adjusting the monthly budget, at any rate.Last one before we close this out: NWC can be used for streaming services where you pay only for what you use, and give yourself a budget. Instead of paying a monthly subscription to Netflix, you could pay per minute that you watch. Previously this could only be done by topping up a wallet controlled by the service itself, the way
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wallet worked with streaming sats for Podcasting 2.0. But now NWC is coming to Fountain, and users can bring their own wallet that they control.The future of NWC is bright, and it extends well beyond zapping memes on Nostr. It's going to open up a world of possibilities for how we can use our sats to stream media, make reoccurring donations, use micro-payments to rent compute, and so much more. I don't know about you, but I am here for it!