I don't disagree with anything you just said, but I think the solution you're trying is potentially even more confusing. I don't have a better idea.

- You are sending/receiving bitcoin, not “sats”

- The asset is bitcoin, the most well-know asset in the world, the symbol should be there

- Sats is very confusing if you’re new to bitcoin. Easy to confuse the asset and unit if you're new. Good to know you have bitcoin and learn more than think you have sats

- There is zero confusion even if you can’t keep pre/suffixes straight since there is a 100m difference in value (if there is then that’s a good problem to have)

- ₿ looks way better than “sats” and is already is a symbol that exists everywhere

Sats is one of the worst UX mistakes in bitcoin, so open to other ideas, just trying one out!

How does this make any sense? Who else is using this crazy standard?

What are the best Cashu wallets and mint server software? Are all the mints just running the Python reference implementation, or isn't there a reference implementation anymore?

Recently, I have been surrounded by people experimenting with various projects, and a common theme among them is the use of cashu as the payment layer. While this fact alone is already great, the best part is to identify users and implementers needs and combining forces to come up with novel solutions.

---

## Subscriptions with Cashu

One of the most remarkable aspects of cashu is that it is a bearer asset. This hands ownership and control back to the user. Even though mints back the tokens, they have no authority to move a token on behalf of a user or any other party. How cool is that?

However, this also introduces challenges when building subscription-based services. Subscriptions typically require periodic payments, and with cashu, users must renew these manually. Currently, there are two primary approaches to address this:

1. **Overpaying:**

To minimize the number of interactions, users can pay for longer periods upfront. For example, instead of paying 2,100 sats for one hour, they could pay 6,000 sats for three hours. If they realize they don’t need the full three hours, the excess payment is effectively wasted.

2. **Full Interactivity:**

In this setup, payers and receivers stay connected through a communication channel, and payments are made at small, regular intervals. While this avoids overpayment, it requires constant connectivity. If the connection is lost, the subscription ends.

---

## Enter Locking Scripts

One of the most powerful features of cashu is its locking scripts. Let’s take a quick refresher. A locking script defines the conditions under which a token (or "nut") becomes spendable. In essence, it’s similar to Bitcoin’s spending conditions, but instead of being enforced by the Bitcoin network, these conditions are enforced by the cashu mint alone.

A widely-used locking condition is Pay-to-Public-Key (P2PK). This locks a token to a specific public key, meaning it can only be spent when a valid signature from the key’s owner is provided. This mechanism is what enables NIP-61 nut zaps, where a token can be publicly shared but is only claimable by the intended recipient who holds the private key.

To address situations where a recipient loses access to their keys or simply doesn’t claim the token, P2PK includes additional options: locktime and a refund key. These options allow for the inclusion of a fallback mechanism. If the primary lock expires after a set time, a refund key can reclaim the token.

With these tools, we can now create non-interactive payment streams!

---

## One Missing Piece…

Before diving into payment streams, there’s one more crucial concept to cover: cashu tokens are not singular "things". Instead, they’re composed of multiple proofs, each carrying its own cryptographic data and spendability. For example, if you receive a cashu token made up of five proofs, you could choose to claim only three proofs and leave the other two untouched. This flexibility is rarely utilized but is vital for building payment streams.

---

## The Grand Finale: Payment Streams

Now that we have all the building blocks, let’s construct a payment stream using cashu. By leveraging locking scripts, refund keys, and multiple proofs, we can design a token that enables recipients to claim small portions of the total amount at regular intervals—without requiring any further interaction from the sender.

Even better, as the sender, you retain the ability to cancel the stream at any time and reclaim any unspent portions.

![Flowchart of payment streams]()

### Example: Renting a VPS

Imagine renting a VPS for a week, priced at 1,000 sats per day. Here’s how a payment stream could work:

1. Construct a token worth 7,000 sats to cover the entire week.

2. Divide the token into 7 proofs, each worth 1,000 sats.

3. Lock each proof using a P2PK script, locking to your key and adding the recipients key as a refund key.

- The first proof has a locktime of `now`.

- The second proof has a locktime of `now + 1 day`.

- The third proof has a locktime of `now + 2 days`, and so on.

When the token is sent, the receiver can immediately claim the first proof since its locktime has expired and the refund key is now able to claim. The second proof becomes claimable after one day, the third after two days, and so on.

At the same time, the sender retains the ability to reclaim any unclaimed proofs by signing with their key. If you decide to stop using the VPS midweek, you can cancel the stream and reclaim the remaining proofs; all without further interaction with the receiver.

---

With this approach, we can create robust, non-interactive payment streams that combine the autonomy of cashu with the flexibility to reclaim funds.

Thank you for reading. Make sure to leave a nut if you enjoyed this :)

It's high trust and easily ruggable though... And it's not secured by Bitcoin network in any way. Cool, yes. For small amounts and groups? Maybe.

For the general masses, I just don't see it?

Payment requests, new gifts and more 🎉

Boardwalk now supports #Cashu payment requests 💸

Easily request and send payments for specific amounts and every user now has a reusable ecash address to receive payments.

Use dollars or bitcoin. Perfect for point of sale or tips.

We also added a bunch of new updates, live now!

🖌️ Multi-color screens for BTC 🟦 and USD 🟩

💵 Currency switch dashboard

⌨️ New keyboard on mobile

🏃 Faster and smoother everything

🎁 New gifts, lots of gifts

Sketched out some talks of nostr:nprofile1qqsvxhlccdqyf8cddzh34mzggja5f2wqhrqa6n6dfmauvhsjqwdrfzspzemhxue69uhhyetvv9ujuurjd9kkzmpwdejhgqg5waehxw309aex2mrp0yhxgctdw4eju6t0qyw8wumn8ghj7mn0wd68ytndw46xjmnewaskcmr9wshxxmmdtsxx9q and @nothingmuch (no nostr?) from nostr:nprofile1qqsxhwmaw842y4zzzk580cfke4l5jr6xyh44v3v6pk59dnyzjm2a7vqcd5flv. Sadly couldn't make it to there, but seemed to be a great technical conference!

So cool for organizing nostr:nprofile1qqsvh300dvquh50l5t9et2257pxrsk5ndsdgdcdmnnxl9nc0f6l2ejcpz3mhxue69uhhyetvv9ujuerpd46hxtnfduq3samnwvaz7tmjv4kxz7fwwdhx7un59eek7cmfv9kqzrrhwden5te0vfexytnfdu7y9l4j!

See me do it live at nostr:nprofile1qqs0zqyq74avavecxlreqte2ugu5hc7q867qwg386pmeflmd00hdnhqpz4mhxue69uhkummnw3ezummcw3ezuer9wchs6tqrzz!

Boardwalk and Bitcoin 🎉

We’re excited to announce our biggest update ever.

Boardwalk now supports #Bitcoin - both through bitcoin eCash and through any bitcoin wallet that supports NWC.

Boardwalk is a Bitcoin platform - combining the best of eCash, Lightning and self-custody.

---

Boardwalk is now the easiest way to experience bitcoin for the first time.

Instantly receive bitcoin by claiming an eCash token, eTip or eGift.

Send your first Bitcoin Lightning payment to a friend or merchant in seconds.

---

Bitcoin eCash enhances the bitcoin payments experience.

Instant onboarding, bearer cash, gifts, dollar-based balances, programmable and offline payments expand the usability of bitcoin.

And eCash is just getting started!

---

Boardwalk is now much more than just an eCash wallet.

Boardwalk is a self-custodial wallet that connects to any bitcoin wallet that supports Nostr Wallet Connect nostr:npub19hg5pj5qmd3teumh6ld7drfz49d65sw3n3d5jud8sgz27avkq5dqm7yv9p

nostr:npub1getal6ykt05fsz5nqu4uld09nfj3y3qxmv8crys4aeut53unfvlqr80nfm nostr:npub1aghreq2dpz3h3799hrawev5gf5zc2kt4ch9ykhp9utt0jd3gdu2qtlmhct nostr:npub126ntw5mnermmj0znhjhgdk8lh2af72sm8qfzq48umdlnhaj9kuns3le9ll

---

No mint? No problem!

Send eCash as an eTip or eGift directly from your own Lightning wallet using NWC.

Receive eCash directly to your own node or favorite Lightning wallet via Lightning Address.

nostr:npub1ex7mdykw786qxvmtuls208uyxmn0hse95rfwsarvfde5yg6wy7jq6qvyt9 nostr:npub155m2k8ml8sqn8w4dhh689vdv0t2twa8dgvkpnzfggxf4wfughjsq2cdcvg nostr:npub1hcwcj72tlyk7thtyc8nq763vwrq5p2avnyeyrrlwxrzuvdl7j3usj4h9rq nostr:npub13ljnkd633c7maxatymv3y2fqq8vt3qk7j3tt0vytv90eztwgha9qmfcfhw

---

Boardwalk combines eCash and NWC to deliver the best bitcoin payments experience.

We will continue to add new bitcoin payments technologies as they develop and scale.

#Cashu #NWC #Fedimint #Ark #Strata

---

We believe these Bitcoin protocols will become the payments infrastructure layers of the future.

All payments will be bitcoin payments.

www.boardwalkcash.com

nostr:npub1cd0l3s6qgj0s6690rtkys39mgj5upwxpm4856nhmce0pyqu6xj9qh7xlvx any thoughts here?

Introducing Boardwalk Prizes 🏆

Prizes are eGift giveaways. Act fast to win!

Look for the 🔥 icon and send the prize to a friend or claim yourself.

Today’s prize is 100 Stars ⭐ - each worth $1 of eCash!

Prizes are one per person and you must link Nostr.

One of these 💗 🍦 🌭 🍭 🧸 🐳

Let’s celebrate our Nostr integration with some eGifts today 🎉

Add your npub to Boardwalk and reply below 👇

We’ll give you a follow and respond with an eGift 💝

nostr:note1f8c9t3th3xc9p6dp084r43fljdkksw0h5j5n6zx4qgpq8stt3ljqf6n54d

Discover Nostr Friends 🫂

We’re thrilled to announce you can now link Boardwalk with your Nostr account!

Just click Discover under your Profile Settings.

See all your friends and add them to your Boardwalk contacts with one click.

Introducing eGifts 🎁

Send virtual gifts to show your appreciation for your friends or favorite creators!

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Enjoy sharing our first collection of eGifts!

💗 🍦 🌭 🍭 🧸 🐳

Our Prism account is now officially our Boardwalk account! Going forward we’ll use this account for all Boardwalk related communications.

Stay tuned for our first big announcement coming tomorrow! 🐳

Would you be open to a PR to make that configurable? If I get time in the next few weeks I’d love to try and add that

Hey Bob, great work on Boardwalk.

Does the UI only support USD denomination or can we choose to show sats? I can’t seem to find that setting.

Hey Bob, can you add the ability to edit contacts (mainly delete)? 🙏