> ## Documentation Index > Fetch the complete documentation index at: https://docs.niadra.com/llms.txt > Use this file to discover all available pages before exploring further. # Create an assertion > States that two handles belong to the same subject, with method and evidence. ## OpenAPI ````yaml openapi/en/cell.json POST /v1/identity/assertions openapi: 3.1.0 info: title: Niadra data API version: '1' description: >- Writing, context, history, objects, identity, privacy and governance of one space. Every space has a stable address, with the space and the region in its name. servers: - url: https://{space}.{region}.api.niadra.com variables: space: default: acme-prod description: The space, which comes in the source key. region: default: us-east-1 description: The region of the space, which also comes in the key. security: [] paths: /v1/identity/assertions: post: tags: - identity summary: Create an assertion description: >- States that two or more handles belong to the same subject, with the method that proves it. The assertion goes through the same protections as the ones the ingestion makes: blocked values, limits per handle type, and never an automatic merge of two profiles that already hold a handle at V3 or above. The merge itself runs outside the request, so the answer is 202 with the operation. **Authentication.** Console person token with the `security`, `integration` role (or admin), or a source key with the `admin` scope. operationId: create_assertion_v1_identity_assertions_post parameters: - in: header name: Idempotency-Key required: true schema: maxLength: 256 minLength: 1 title: Idempotency-Key type: string description: >- Required. Kept 24 hours with the hash of the body: a retry with the same key returns the first answer, and the same key with a different body returns 409 `conflict`. requestBody: content: application/json: schema: $ref: '#/components/schemas/AssertionIn' example: handles: - type: phone_e164 value: '+14155550123' - type: system_id value: '48213' scope: crm method: system_import subject_kind: person reason: CRM contact record 48213 required: true responses: '202': content: application/json: schema: $ref: '#/components/schemas/OperationOut' example: op_id: 0192f7a1-5b10-7c3a-8e21-4d2f8a4c0e07 status: queued assertion_id: 0192f7a1-5b10-7c3a-8e21-4d2f8a4c0e06 link_id: null description: The operation, queued or applied. '422': content: application/problem+json: schema: $ref: '#/components/schemas/Problem' description: The request does not match the contract. security: - sourceKey: [] - personToken: [] components: schemas: AssertionIn: additionalProperties: false properties: handles: items: $ref: '#/components/schemas/Handle' maxItems: 2 minItems: 2 title: Handles type: array method: $ref: '#/components/schemas/AssertionMethod' default: explicit_identify reason: anyOf: - maxLength: 500 minLength: 1 type: string - type: 'null' title: Reason subject_kind: $ref: '#/components/schemas/SubjectKind' default: person required: - handles title: AssertionIn type: object OperationOut: additionalProperties: false properties: assertion_id: anyOf: - format: uuid type: string - type: 'null' title: Assertion Id link_id: anyOf: - format: uuid type: string - type: 'null' title: Link Id op_id: format: uuid title: Op Id type: string status: enum: - queued - applied - linked - blocked title: Status type: string required: - op_id - status title: OperationOut type: object Problem: additionalProperties: false description: RFC 9457 problem details; `code` comes from the versioned error catalog. properties: code: title: Code type: string detail: anyOf: - type: string - type: 'null' default: null title: Detail request_id: anyOf: - type: string - type: 'null' default: null title: Request Id status: title: Status type: integer title: title: Title type: string type: default: about:blank title: Type type: string required: - title - status - code title: Problem type: object Handle: additionalProperties: false description: >- An identifier of a subject in some channel or system: a phone, an e-mail, a CRM id. properties: scope: anyOf: - maxLength: 256 minLength: 1 type: string - type: 'null' description: >- Namespace for scoped identifiers: the WhatsApp Business account for `wa_bsuid`, the system for `system_id`, the country for `gov_id_hmac`. title: Scope subject_kind: anyOf: - $ref: '#/components/schemas/SubjectKind' - type: 'null' description: Defaults to `person`, except for organization-only handle types. type: $ref: '#/components/schemas/HandleType' value: maxLength: 320 minLength: 1 title: Value type: string description: >- The identifier. Normalized on the server: E.164 for phones, lowercase for e-mail. required: - type - value title: Handle type: object AssertionMethod: enum: - explicit_identify - otp - login - system_import - same_event - co_occurrence - channel_rotation - accepted_suggestion - external_resolver - declared title: AssertionMethod type: string description: How the link between two handles was established. SubjectKind: enum: - person - account - partner title: SubjectKind type: string description: >- A person, a customer organization (`account`) or an organization that takes part without being a customer (`partner`). HandleType: enum: - phone_e164 - wa_id - wa_jid - wa_lid - wa_bsuid - email - gov_id_hmac - app_user_id - system_id - org_registry_hmac - email_domain - anon_id title: HandleType type: string description: >- The kind of identifier. The value is classified by its format, never by the field it came from. securitySchemes: sourceKey: type: http scheme: bearer description: nia_sk_... personToken: type: http scheme: bearer bearerFormat: JWT ````