nips/45.md
Mariano Pérez Rodríguez 1f89a2ad49
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# Via fiatjaf
* origin/master:
  nip01: remove misleading markdown example.
  Rephrase Markdown special rule
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  Clarify how NIP 45 works with multiple COUNT filters. (#504)

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#	01.md
2023-05-08 11:11:36 -03:00

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NIP-45

Event Counts

draft optional author:staab

Relays may support the verb COUNT, which provides a mechanism for obtaining event counts.

Motivation

Some queries a client may want to execute against connected relays are prohibitively expensive, for example, in order to retrieve follower counts for a given pubkey, a client must query all kind-3 events referring to a given pubkey only to count them. The result may be cached, either by a client or by a separate indexing server as an alternative, but both options erode the decentralization of the network by creating a second-layer protocol on top of Nostr.

Filters and return values

This NIP defines the verb COUNT, which accepts a subscription id and filters as specified in NIP 01 for the verb REQ. Multiple filters are OR'd together and aggregated into a single count result.

["COUNT", <subscription_id>, <filters JSON>...]

Counts are returned using a COUNT response in the form {"count": <integer>}. Relays may use probabilistic counts to reduce compute requirements.

["COUNT", <subscription_id>, {"count": <integer>}]

Examples:

# Followers count
["COUNT", <subscription_id>, {"kinds": [3], "#p": [<pubkey>]}]
["COUNT", <subscription_id>, {"count": 238}]

# Count posts and reactions
["COUNT", <subscription_id>, {"kinds": [1, 7], "authors": [<pubkey>]}]
["COUNT", <subscription_id>, {"count": 5}]