NIP-54
======

Podcasts
--------

`draft` `optional`

This NIP defines how podcast episodes can be fetched from relays. It's intended to fit easily into existing podcast players.

## Rationale

RSS feeds are great, but they have some problems that are solved by moving feeds from RSS URLs to multiple Nostr events, one for each episode:

- they depend on a URL and that is hard for most people, so podcasters tend to use service providers that can
   - charge money -- which isn't a bad thing per se but it turns out that with a Nostr-native podcast feed protocol it would be much simpler to host feeds and infinitely cheaper to host the media, so the ecosystem could be more decentralized
   - seal them into their walled gardens (like Spotify has been doing), slowly turning a previously open ecosystem into a centralized system captured by big corporations
   - censor podcasters and prevent them from migrating (on Nostr this wouldn't be a problem even if a relay banned someone as moving to other relays would be trivial as long as the podcaster held their key and podcast clients could easily discover the new relay URLs)
- they can only be loaded in full, with no pagination or filtering of any kind, which means that
   - the sync process in normal RSS clients is slow and cumbersome (which also nudges people into using centralized solutions)
     - this has also led to the creation of broken schemes like [Podping](https://podping.org/), which wouldn't be necessary in a Nostr-native podcast feed
   - It's impossible to reference a single episode directly (since it only exists as a member in the full RSS list of episodes), this means there is no way to share a podcast episode with friends or on social media, so people tend to share links to centralized platforms or to YouTube videos of the same podcast content, which is an antipattern
- they cannot be interacted with in any way: listeners cannot "like" or comment or signal that they have listened to the episode, which is also another factor in the push towards centralized closed platforms: better analytics and insights and possibilities of engagement with the public

## Event definitions

### Podcast Profile

Podcasts have their own key and their own [NIP-01](01.md) `kind:0` profile, but with a tag `["type", "podcast"]` that can be used to signal that they have podcast episodes published.

### Podcast Episodes

Podcast episodes are `kind:54` with some tags:

```jsonc
{
  "id": "55807e7d5cd90d0303d7dce7397f996fdbaed8697903f326c7cf8ad999b9de3d",
  "pubkey": "79be667ef9dcbbac55a06295ce870b07029bfcdb2dce28d959f2815b16f81798",
  "kind": 54,
  "created_at": 1700682555,
  "tags": [
    ["title", "<episode title>"],
    ["image", "<optional episode image>"],
    ["description", "<a brief description>"],
    ["audio", "https://.../", "<optional_media_type>"], // can be specified multiple times
    ["t", "<optional tag>"], // can be specified multiple times
    ["alt", "<optional NIP-31 short description for displaying in incompatible clients>"]
  ],
  "content": "<markdown content (or what is supported in RSS feeds content nowadays?)>",
  "sig": "...",
}
```

### Podcast Comments

These are normal text comments like `kind:1`, but specific for podcast episodes.

```jsonc
{
  "id": "606f6c703f04c70806a5c2830e3853bd83c44985b1f282a070ba894add3724b0",
  "pubkey": "b2c5d5bf69d14d35c25fa47d5c67896b13394136734065a371c5bf2c62f905d2",
  "kind": 55,
  "created_at": 1700682556,
  "tags": [
    ["e", "55807e7d5cd90d0303d7dce7397f996fdbaed8697903f326c7cf8ad999b9de3d"],
  ],
  "content": "<plain text content>",
  "sig": "...",
}
```

(It's unclear if it's best to use this or a generic kind for commenting on stuff that isn't `kind:1`.)

### Reactions (likes), zaps and reposts

These work normally according to their own NIPs.

### To be added:

- "read" events, signaling that a user has listened to a given podcast, perhaps just use https://github.com/nostr-protocol/nips/pull/933