Every Nostr event is already timestamped. So why a dedicated evidence kind?
Because a kind 1 note with a SHA-256 hash in the text is human-readable but not machine-parseable. NIP-EVIDENCE (kind 30578) adds structured metadata that makes evidence filterable, verifiable, and composable.
One kind. Tags for: evidence type (photo, video, document, reading, observation), file hash, capture timestamp, geolocation, condition grade, and chain linkage to related events.
Not all evidence is file-based. Sensor readings, condition assessments, verbal confirmations, and witnessed observations have no associated file. NIP-94 requires a file URL; NIP-EVIDENCE does not.
NIP-03 (OpenTimestamps) proves an event existed at a time. NIP-EVIDENCE adds what was captured, where, when, and under what conditions. The two complement each other.
Useful for inspections, insurance claims, compliance audits, dispute resolution, or any workflow where "signed facts" need to be discoverable by type, location, or related event.
Build with this: a citizen journalism tool where photos carry verifiable metadata about when and where they were taken. A home renovation log where before/after photos are timestamped and geolocated. A birdwatching app where sightings carry structured evidence. A community mapping project where contributors submit verified survey data.
https://github.com/forgesworn/nip-drafts/blob/main/NIP-EVIDENCE.md