1NIP-502======34Search Capability5-----------------67`draft` `optional` `relay`89## Abstract1011Many Nostr use cases require some form of general search feature, in addition to structured queries by tags or ids. 12Specifics of the search algorithms will differ between event kinds, this NIP only describes a general 13extensible framework for performing such queries.1415## `search` filter field 1617A new `search` field is introduced for `REQ` messages from clients:18```yaml19{20 // other fields on filter object...21 "search": <string>22}23```24`search` field is a string describing a query in a human-readable form, i.e. "best nostr apps". 25Relays SHOULD interpret the query to the best of their ability and return events that match it. 26Relays SHOULD perform matching against `content` event field, and MAY perform27matching against other fields if that makes sense in the context of a specific kind. 2829Results SHOULD be returned in descending order by quality of search result (as defined by the implementation),30not by the usual `.created_at`. The `limit` filter SHOULD be applied after sorting by matching score.31A query string may contain `key:value` pairs (two words separated by colon), these are extensions, relays SHOULD ignore 32extensions they don't support.3334Clients may specify several search filters, i.e. `["REQ", "", { "search": "orange" }, { "kinds": [1, 2], "search": "purple" }]`. Clients may 35include `kinds`, `ids` and other filter field to restrict the search results to particular event kinds.3637Clients SHOULD use the supported_nips field to learn if a relay supports `search` filter. Clients MAY send `search` 38filter queries to any relay, if they are prepared to filter out extraneous responses from relays that do not support this NIP.3940Clients SHOULD query several relays supporting this NIP to compensate for potentially different 41implementation details between relays.4243Clients MAY verify that events returned by a relay match the specified query in a way that suits the44client's use case, and MAY stop querying relays that have low precision.4546Relays SHOULD exclude spam from search results by default if they support some form of spam filtering.4748## Extensions4950Relay MAY support these extensions:51- `include:spam` - turn off spam filtering, if it was enabled by default52- `domain:<domain>` - include only events from users whose valid nip05 domain matches the domain53- `language:<two letter ISO 639-1 language code>` - include only events of a specified language54- `sentiment:<negative/neutral/positive>` - include only events of a specific sentiment55- `nsfw:<true/false>` - include or exclude nsfw events (default: true)