NIP-88 ====== Recurring Subscriptions ----------------------- `draft` `optional` `author:pablof7z` This NIP defines a way for a pubkey to create recurring subscription payments to another pubkey. ## Tier Event A pubkey can create "tiers". These tiers might provide certain benefits to the supporters who subscribe to these. ```json { "kind": 37001, "content": "", "tags": [ [ "title", "..." ], [ "image", "..." ], [ "amount", "", "currency", "" ], [ "amount", "", "currency", "" ] ] } ``` This event is generated by a pubkey who wants to allow users to support with different tiers. `.content` SHOULD be a description of what users who subscribe can expect. Tag `title` is an optional title for the tier. Tag `image` is an optional image for the tier. Tag `amount` MUST specify the payment required for this tier and its cadence. * The first argument should be the stringified amount and the second argument the currency * The third argument SHOULD be one of `daily`, `monthly`, `yearly` One or more `amount` tags MUST exist. #### Examples * `[ "amount", "100", "usd", "daily" ]`, $1.00 a day. * `[ "amount", "1000000", "msats", "daily" ]`, 1000000 millisats a day. ## Subscribe Event ```json { "kind": 7001, "content": "", "tags": [ [ "p", "" ], [ "a", "" ], [ "event", "" ], [ "amount", "", "currency", "" ] ] } ``` When a user wants to subscribe to support a user they create a `kind:7001` event. * `.content` is an optional message the supporter can write. * The `p` tag MUST tag the pubkey being supported. * The `a` tag is optional; it should point to a `kind:37001` support tier event. There MUST be exactly 0 or 1 `a` tag. * The `event` tag is optional; subscribers can opt to keep the version of the event they subscribed to. There MUST be exactly 0 or 1 `event` tag. * The `amount` tag specifies what the supporters is committing to pay to the supported pubkey and the candence. MUST be equal to one of the amounts specified in the `kind:37001` event. There MUST be exactly 1 `amount` tag. The `kind:7001` event can be created without an `e` tag so that users can create recurring support events without the pubkey receiving the support having explicitly created a support tier. ## Paying The supporting user should create a zap `p`-tagging the receiver and e-tagging the `kind:7001`. There MUST be a single `p` and a single `e` tag in the zap request. ```json { "kind": 9734, "content": "", "tags": [ [ "p", "" ], [ "e", "" ] ] ``` Clients supporting this NIP can check for zaps e-tagging the `kind:7001` event to find the pubkeys that have a valid, paid subscriptions at each different period. The same `kind:7001` is re-zapped on a regular basis per the cadence specified in the event. ## Verifying Payment The following conditions must be met to verify a payment: * Time between zap receipts should be equal or less than the cadence specified in the `kind:7001` event. * Amount of the zap receipt should be equal or greater than the amount specified in the `kind:7001` event. For currencies not directly supported by the zap spec, clients should do a best effort conversion to the currency specified in the `kind:7001` event at the time of zap receipt. * Zap-receipts should include a zap request `e`-tagging the `kind:7001` event. Zap-receipts might not include a signature (for NWC-automated payments where the subscriber is not present to sign the zap request). * Validations specified in [NIP-57](https://github.com/nostr-protocol/nips/blob/master/57.md). ## Stopping a subscription A user who wants to signal they are no longer subscribed can publish a `kind:7002` event tagging the `kind:7001` they are stopping and `p`-tagging the pubkey they are no longer subscribed to. ```json { "kind": 7002, "content": "", "tags": [ [ "p", "" ], [ "e", "" ], ] } ```