Attestations

Published Mar 25, 2026

kind 31871kind 31872kind 31873kind 11871

Abstract

Nostr lacks a standardized, interoperable way to make, track, and revoke truthfulness claims about Nostr events.

This NIP introduces Attestations, which provides a base structure to:

Make attestations about that validity of any other event on Nostr of any kind;
Revoke attestations about previous validity claims.

This base Attestation structure can optionally be extended to:

Manage simple attestation lifecycles;
Request attestations from other npubs;
Recommend individual attestation providers based on their proficiency in verifying given kinds;
Publish your verification proficiency for given kinds.

Attestations enable a web of-trust for notes.

Definitions

Base Definitions

Entity	Definition
`Assertor`	Signer of the `Assertion Event`. Interchangeable with Attestee.
`Attestor`	Verifying party and signer of the`Attestation Event`.
`Assertion Event`	Event being attested to by the `Attestor`.
`Attestation Event`	Event published by the `Attestor` to signal attestation of the `Assertion Event`.

!Simple Entity Relationship Diagram

erDiagram
    ATTESTOR ||--o{ ATTESTATION_EVENT : signs
    ASSERTOR ||--o{ ASSERTION_EVENT : signs
	
	ATTESTATION_EVENT ||--|| ASSERTION_EVENT : attests_to

Extended Definitions

Entity	Definition
`Requestor`	Signer of the `Attestation Request Event`.
`Reccomender`	Signer of the `Attestation Recommendation Event`.
`Attestation Request Event`	The request for an `Attestation Event` from an `Attestor`.
`Attestor Recommendation Event`	The recommendation of a given `Attestor` for proficiency in the verification of given kinds.
`Attestor Proficiency Declaration Event`	A declaration of proficiency from a given `Attestor` in the verification of given kinds.

!Extended Entity Relationship Diagram

erDiagram
    ATTESTOR o|--o{ ATTESTATION_EVENT : signs
    ATTESTOR o|--|| ATTESTOR_PROFICIENCY_DECLARATION_EVENT : signs
    ASSERTOR o|--o{ ASSERTION_EVENT : signs
    ASSERTOR o|--o{ ATTESTATION_REQUEST_EVENT : signs
	REQUESTOR o|--o{ ATTESTATION_REQUEST_EVENT : signs
	RECOMMENDER o|--o{ ATTESTOR_RECOMMENDATION_EVENT : signs
	
	ATTESTATION_EVENT ||--|| ASSERTION_EVENT : attests_to
    ATTESTATION_REQUEST_EVENT ||--|| ASSERTION_EVENT : requests_attestation_of
    ATTESTOR_RECOMMENDATION_EVENT ||--|| ATTESTOR: recommends
    ATTESTOR_PROFICIENCY_DECLARATION_EVENT ||--|| ATTESTOR: declares_proficiency_of

Specification

Event Kinds

Kind	Description	Type
`31871`	Attestation	Addressable
`31872`	Attestation Request	Addressable
`31873`	Attestor Recommendation	Addressable
`11871`	Attestor Proficiency Declaration	Replaceable

Tags

Attestation Event (`31871`)

Event signed by the Attestor. The Attestor should only sign an Attestation Event after verifying the validity of the Assertion Event to a degree appropriate for its kind type.

Tag	Description	Format	Required
`d`	Unique identifier for addressable attestation.	`["d", "<npub>:my-claim-id"]`	Yes
`e` / `a`	Specific `Assertion Event`. Exactly one of `e` or `a` must be present.	`["e", "<event-id>"]` or `["a", "<kind>:<pubkey>:<d-tag>"]`	Yes
`s`	Marks an Attestation as being in only one of the following states: `verifying` - `valid` - `invalid` - `revoked`	`["s","verifying" <> "valid" <> "invalid" <> "revoked"]`	Yes
`valid_from`	Unix timestamp (seconds). The earliest time (inclusive) at which the attestation is valid from. Clients should interpret the absence of `valid_from` tag as having `validity`/`invalidity` from the `created_at` timestamp of the `Assertion Event`	`["valid_from",1671217411]`	Optional
`valid_to`	UNIX timestamp (seconds). The latest time (inclusive) at which the attestation is valid from. Clients should interpret the absence of `valid_to` tag as having `validity`/`invalidity` in perpetuity.	`["valid_from",1671567643]`	Optional
`expiration`	UNIX timestamp (seconds). The time (inclusive) at which the `Attestation Event` will expire and be treated as such by relays in accordance to `NIP-40`. Clients should set this it be the same value as `valid_to` if there is no value in the `Attestation Event` being long-lived.	`["expiration",1671567643]`	Optional
`request`	`Attestation Request Event` that prompted this attestation.	`["request", "31872:<requestor_pubkey>:<d-tag>"]`	Optional

content key should be used for optional human-readable description.

Attestation Request (`31872`)

Event signed by the Requestor (usually the Assertor) requesting an Attestation Event from an Attestor.

Tag	Description	Format	Required
`d`	Unique identifier for addressable attestation request.	`["d", "<requestor_pubkey>:my-request-id"]`	Yes
`e`/`a`	Specific `Assertion Event` Exactly one of `e` or `a` must be present.	`["e", "<event-id>"]` or `["a", "<kind>:<pubkey>:<d-tag>"]`.	Yes
`p`	One or more requested `Attestators`. Repeatable.	`["p", "<attestor_pubkey1>"]`	No
`cashu_token`	A Cashu token locked to given spending conditions (HLTC, P2PK, etc.). Spending conditions may be locked to the observation of requested `Attestation Events`.	`["cashu_token", "<cashuBo...>"]`	No

Attestor Recommendation (`31873`)

Event signed by the Recommender.

Allows any npub to recommend an Attestor for verification proficiency in one or more event kinds.

Tag	Description	Format	Required
`d`	Unique identifier for the recommendation.	`["d", "<attestor_pubkey>:<recommendationid>`	Yes
`p`	Pubkey of recommended `Attestator`.	`["p", "<attestor_pubkey>"]`
`k`	One or more event kinds the attestor is recommended for verifying. Repeatable.	`["k", "<kind1>"]`	Yes

content key should be used for optional human-readable description.

Attestor Proficiency Declaration (`11871`)

Event signed by the Attestor.

Enables an attestor to publicly declare which event kinds they are proficient in verifying; facilitating discovery of suitable attestors for specific verification needs.

Tag	Description	Format	Required
`k`	One or more event kinds the attestor claims verification proficiency in. Repeatable.	`["k", "<kind>,"]`	Yes

content key should be used for optional human-readable description.

Worked Examples

1. Attestation Request

{
  "kind": 31872,
  "tags": [
	["d", "npub1requestor...:my-request-id"],
    ["a", 12345:npub1...:central-park-saftey-assertation"],
    ["p", "npub1attestor1..."]
    ["p", "npub1attestor2..."]
  ],
  "content": "Verify safety status for Central Park"
}

2. Attestation

{
  "kind": 31871,
  "tags": [
    ["d", "npub:safety-verification-2025"],
    ["a", "12345:npub1...:central-park-saftey-assertation"],
    ["s", "valid"],
    ["valid_from", "1760227200"], // Sept 12, 2025 @ 00:00 UTC
    ["valid_to",   "1760486400"],  // Sept 15, 2025 @ 00:00 UTC
    ["request", "request-event-id-123"]
  ],
  "content": "Safety inspection valid"
}

3. Revocation

{
  "kind": 31871,
  "tags": [
    ["d", "npub:safety-verification-2025"],
    ["s", "revoked"]
  ],
  "content": "Retracted due to new safety concerns"
}

Related NIPs

NIP-03 - OpenTimeStamps Attestations

An Attestor, Assertor or any other npub may choose to issue a kind:1040 OpenTimestamps Attestations for Events event to anchor the Attestation Event to a given blockheight on the Bitcoin timechain.

NIP-58 - Badges

An Attestor or any other npub may choose to issue a badge for a given Attestation should they wish.

Attestations

Abstract

Definitions

Base Definitions

Extended Definitions

Specification

Event Kinds

Tags

Attestation Event (31871)

Attestation Request (31872)

Attestor Recommendation (31873)

Attestor Proficiency Declaration (11871)

Worked Examples

1. Attestation Request

2. Attestation

3. Revocation

Related NIPs

NIP-03 - OpenTimeStamps Attestations

NIP-58 - Badges

Attestation Event (`31871`)

Attestation Request (`31872`)

Attestor Recommendation (`31873`)

Attestor Proficiency Declaration (`11871`)