NIP-92 enables users to attach media files to Nostr events by including URLs alongside inline metadata tags that describe those resources.

How It Works

Users place media URLs directly in event content, for example in a kind 1 text note. A matching imeta tag then adds machine-readable details for that exact URL. Clients can use the metadata to render previews, reserve layout space, and avoid guessing file properties after the note is already on screen.

Each imeta tag should match one URL in the event content. Clients may ignore tags that do not match, which gives implementations a simple rule for rejecting stale or malformed metadata.

The imeta Tag

Each imeta tag must have a url and at least one other field. Supported fields include:

  • url - The media URL (required)
  • m - MIME type of the file
  • dim - Image dimensions (width x height)
  • blurhash - Blurhash for preview generation
  • alt - Alt text description for accessibility
  • x - SHA-256 hash (from NIP-94)
  • fallback - Alternative URLs if primary fails

Because imeta may carry fields from NIP-94: File Metadata, clients can reuse the same MIME type, dimensions, hash, and accessibility text they would already understand for standalone file metadata events.

Why It Matters

The most immediate benefit is better rendering before download. If dim is present, clients can reserve the right amount of space for an image or video instead of reflowing the timeline after the file loads. If blurhash is present, they can show a low-cost preview first. If alt is present, the attachment stays usable for screen-reader and low-vision users.

NIP-92 also lets clients keep the post itself as the source of truth. The URL remains in content, so older clients still show a plain link, while newer clients can upgrade the same note into a richer media card.

Interop Notes

NIP-92 is inline metadata, not a separate media object format. If a client needs a reusable file record with its own event, NIP-94: File Metadata is the better fit.

Example

["imeta",
  "url https://example.com/image.jpg",
  "m image/jpeg",
  "dim 1920x1080",
  "blurhash LKO2?U%2Tw=w]~RBVZRi}^Xu%LRj"
]

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