NIP-47 notifications

[rolznz]

This allows the wallet service to asynchronously send notifications to connected clients as an alternative to polling.

Example usecases:

• Realtime balance, invoice status, and transaction list updates

Currently two notification types are defined - payment_received and payment_sent.

This has been implemented in:

• Alby's Nostr Wallet Connect app ("Next" version) feat: NIP-47 subscriptions getAlby/nostr-wallet-connect-next#183
• Alby JS SDK feat: subscribe to NIP-47 notifications getAlby/js-sdk#217
• BTCPayServer (Nostr Plugin) https://github.com/Kukks/NNostr/blob/master/NNostr.Client/Protocols/NIP47.cs#L182
• http-nostr https://github.com/getAlby/http-nostr
• YANA
• Alby Go

There are also some minor copy updates to communicate that NWC is not just for sending payments, but a protocol for connecting apps to lightning wallets.

Currently the notification type is encrypted in the payload, similar to existing responses. The downside is that clients cannot filter notifications - they would get all or none (or would have to be filtered on the wallet service level which is currently outside the spec).

[vitorpamplona]

+1. Anything is better than request/response

[Kukks]

Please provide an event JSON example, as this isn't very clear.

[rolznz]

The example is given: payment_received balance_changed. It's a standard tag as per NIP-01.

However, for a full example I have fetched the info event here from my current NWC wallet (note: there's only payment_received as only one notification type is implemented so far):

{
  "id": "df467db0a9f9ec77ffe6f561811714ccaa2e26051c20f58f33c3d66d6c2b4d1c",
  "pubkey": "c04ccd5c82fc1ea3499b9c6a5c0a7ab627fbe00a0116110d4c750faeaecba1e2",
  "created_at": 1713883677,
  "kind": 13194,
  "tags": [
    [
      "notifications",
      "payment_received"
    ]
  ],
  "content": "pay_invoice pay_keysend get_balance get_info make_invoice lookup_invoice list_transactions multi_pay_invoice multi_pay_keysend sign_message notifications",
  "sig": "31f57b369459b5306a5353aa9e03be7fbde169bc881c3233625605dd12f53548179def16b9fe1137e6465d7e4d5bb27ce81fd6e75908c46b06269f4233c845d8"
}

[Kukks]

Yeah, I know. I meant to add it to the spec to make it more obvious and clear for implementors.

[Kukks]

ACK, implemented in NNostr https://github.com/Kukks/NNostr/blob/master/NNostr.Client/Protocols/NIP47.cs#L182

[rolznz]

EDIT: Added a few new things to this PR:

• add payment_sent notification kind
• add notifications as an optional field in the get_info command response (because permissions can be set at an app connection level, not just the capabilities at the wallet service level)
• appendix of example output as Kukks mentioned
• optional fees_paid on payment command responses

[Kukks]

EDIT: Added a few new things to this PR:

• add payment_sent notification kind
• add notifications as an optional field in the get_info command response (because permissions can be set at an app connection level, not just the capabilities at the wallet service level)
• appendix of example output as Kukks mentioned
• optional fees_paid on payment command responses

Kukks/NNostr@7b7aa2e

[frnandu]

Yana just added support for these notifications in https://github.com/frnandu/yana/releases/tag/v0.15.0
Can this be merged now?

[rolznz]

@fiatjaf can we merge this?