> ## Documentation Index > Fetch the complete documentation index at: https://docs.topsort.com/llms.txt > Use this file to discover all available pages before exploring further. # [Beta] Report Link Users > Use the `/events/beta/link-users` endpoint to report to Topsort linked opaque user IDs. This endpoint allows linking two opaque user IDs for attribution purposes. The `from` field represents the original opaque user ID, and the `to` field represents the target opaque user ID to be linked. The request will fail if the `from` and `to` opaque user IDs are the same. Contact your sales representative to gain access to this endpoint and start using it. ## OpenAPI ````yaml /openapi.json post /v2/events/beta/link-users openapi: 3.1.0 info: title: Topsort Endpoints v2 API Reference description: > In order for a storefront to be able to run auctions in Topsort and report auction-related events back to Topsort, both the `/v2/auctions` and `/v2/events` endpoints must be integrated. Below are the endpoint and model definitions for each. contact: email: wicha@topsort.com license: name: Apache 2.0 url: http://www.apache.org/licenses/LICENSE-2.0.html x-logo: url: https://assets.topsort.com/Topsort_logo_icon_dark.svg backgroundColor: '#fff' altText: Topsort version: 2.0.0 servers: - url: https://api.topsort.com description: Base API URL security: [] tags: - name: Auctions description: >- An auction determines which products should be promoted based on the vendors' bids. - name: Events description: >- Events are sent to Topsort as part of the attribution and reporting journey. - name: Toptimize description: > An out-of-the-box solution for prediction, ranking, retrieval, and other elements of ad selection. - name: Toppie API description: Toppie management API. - name: Campaign API description: Full-featured campaign management API for banners and sponsored listings. - name: Catalog API description: Products catalog management API. - name: Billing API description: Marketplace and Vendor Billing management API. - name: Reporting API description: Marketplace, Vendor, Campaign, and product reporting API. - name: Invitation API description: Vendor invitations management API. - name: User API description: User management API. - name: Webhooks API description: Webhooks API that allows event-driven automation. - name: Assets API description: Assets management API. - name: Segments Service description: Segments Service. - name: Forecasting Service description: Toptimize Forecasting Service. - name: Offsite Ads API description: Offsite Ads API that allows to manage offsite ads campaigns. - name: Media API description: Ad configuration API. paths: /v2/events/beta/link-users: post: tags: - Events summary: '[Beta] Report Link Users' description: > Use the `/events/beta/link-users` endpoint to report to Topsort linked opaque user IDs. This endpoint allows linking two opaque user IDs for attribution purposes. The `from` field represents the original opaque user ID, and the `to` field represents the target opaque user ID to be linked. The request will fail if the `from` and `to` opaque user IDs are the same. Contact your sales representative to gain access to this endpoint and start using it. operationId: linkUsers requestBody: description: Request to link multiple user IDs that represent the same user. content: application/json: schema: type: object properties: from: type: string description: The opaque user ID of the original user account. minLength: 1 maxLength: 64 examples: - user_abc123 to: type: string description: The opaque user ID of the target user account to be linked. minLength: 1 maxLength: 64 examples: - user_xyz789 required: - from - to examples: default: value: from: user123 to: user456 required: true responses: '204': description: Users account link was reported successfully. '400': $ref: '#/components/responses/Topsort_Endpoints_v2_API_Reference_BadRequest' '401': $ref: >- #/components/responses/Topsort_Endpoints_v2_API_Reference_UnauthorizedError security: - Topsort_Endpoints_v2_API_Reference_HTTPBearer: [] components: responses: Topsort_Endpoints_v2_API_Reference_BadRequest: description: HTTP status codes as registered with IANA. content: application/json: schema: $ref: '#/components/schemas/Topsort_Endpoints_v2_API_Reference_Error' Topsort_Endpoints_v2_API_Reference_UnauthorizedError: description: Access token is missing or invalid schemas: Topsort_Endpoints_v2_API_Reference_Error: description: >- Error response object containing error code, message, and documentation URL. type: object required: - errCode properties: errCode: type: string description: A short string uniquely identifying the problem. enum: - bad_request - empty_request - internal_server_error - invalid_api_key - invalid_auction_id - invalid_demand_source - invalid_event_type - invalid_external_bid - invalid_external_demand_ad_type - invalid_promotion_type - invalid_session - missing_auctions - missing_context - missing_placement - missing_product_id - missing_promotion_type - missing_purchased_at - missing_session - missing_slot_id - missing_slots - no_products - no_purchase_items - purchase_item_quantity_less_or_equal_than_zero - resolved_bid_id_not_found - too_few_impressions - too_few_slots - too_many_auctions - too_many_external_bids - unauthorized_external_demand examples: - bad_request - no_products docUrl: type: string format: uri description: >- A link to a documentation page providing more information about the error. examples: - https://api.docs.topsort.com/reference/errors message: type: string description: > Human-readable explanation of or details about the error. The string for a given error may change over time; code should not parse or dispatch based on particular values for this field. examples: - could not find the provided resolved bid id securitySchemes: Topsort_Endpoints_v2_API_Reference_HTTPBearer: description: >- A valid API key generated in Topsort's UI. Use a TSE API key for calls to Auctions or Events API. scheme: bearer type: http ````