> ## Documentation Index > Fetch the complete documentation index at: https://docs.repdata.com/llms.txt > Use this file to discover all available pages before exploring further. # PREDUPE (POST) Checks for duplicates across multiple survey numbers (projects) on destination platforms, using traffic from another client. This is the standalone PREDUPE API on `prod.search.resdefio.com`; it is read-only and does not record a survey number that isn't already found. * Up to **30 survey numbers** are processed per request across all destinations. If the total exceeds the limit, entries are processed randomly. * Send the request body as JSON with a `Destination` array. Each entry has the destination `Platform_Id` and its `Survey_Numbers`. Look up platform IDs with [DESTINATION\_PLATFORM](/research-defender/endpoints/get-api-v3-respondents-destination_platforms-private_key). * Authenticate with the `x-api-key` header. Send the respondent's IP address, cookie, and user agent in `rd-ip-address`, `rd-cookie`, and `rd-user-agent`. * `Panel_Id`, `Hashed_Email`, `Supplier_Id`, and `Session_Id` are optional. They replace `rt_sr_pd`, `rt_hd_el`, `pm_sr_id`, and `sn_ud` from SEARCH on `rtymgt.com`. The GET variant takes the same body and returns the same result: [PREDUPE (GET)](/research-defender/endpoints/get-predupes). See the [Predupe Integration guide](/research-defender/guides/predupe/02-integration) for a full browser sample. See the [PREDUPE guide](/research-defender/guides/predupe/01-overview) for the field definitions. ## OpenAPI ````yaml POST /predupes openapi: 3.0.3 info: title: Research Defender API version: 1.0.0 description: >- Research Defender protects survey data quality through digital fingerprinting, duplication detection, and open-end text analysis. This reference covers the **SEARCH**, **REVIEW**, and **PREDUPE** products. > ACTIVITY and VERIFY are hosted on a separate domain (resdefio.com) and are documented separately. ## Authentication Client-side calls (SEARCH, REVIEW, GETTOKEN) use your **publishable key** in the URL path. Server-side lookups (destination_platforms) use your **private key**. For enhanced protection, use V3 server-to-server tokens (GETTOKEN) or V4 Hashed Validation. ## Environments Production: `https://prod.rtymgt.com` Staging: `https://staging.rtymgt.com` servers: - url: https://prod.rtymgt.com description: Production - url: https://staging.rtymgt.com description: Staging security: [] paths: /predupes: servers: - url: https://prod.search.resdefio.com description: Production - url: https://stage.search.resdefio.com description: Stage post: summary: PREDUPE (POST) operationId: Predupe_Post parameters: - name: rd-ip-address in: header required: false description: The respondent's IP address. schema: type: string - name: rd-cookie in: header required: false description: The respondent's Research Defender cookie. schema: type: string - name: rd-user-agent in: header required: false description: The respondent's browser user agent. schema: type: string requestBody: required: true content: application/json: schema: type: object properties: Destination: type: array description: >- Destination platforms and the survey numbers to check on each. A maximum of 30 survey numbers are processed per request; beyond that, entries are processed randomly. items: type: object required: - Platform_Id - Survey_Numbers properties: Platform_Id: type: string description: >- Destination platform ID (`destination_platform_id`) to check the traffic with. Use the DESTINATION_PLATFORM lookup to find it. Survey_Numbers: type: array items: type: string description: >- One or more survey numbers on the destination platform. example: - 2025_09 Panel_Id: type: string description: Panelist ID. Optional. Formerly `rt_sr_pd` on SEARCH. Hashed_Email: type: string description: Hashed email. Optional. Formerly `rt_hd_el` on SEARCH. Supplier_Id: type: string description: >- Supplier ID, for reporting only. Optional. Formerly `pm_sr_id` on SEARCH. Session_Id: type: string description: >- Session ID that identifies the transaction. Optional. Formerly `sn_ud` on SEARCH. required: - Destination responses: '200': description: Duplicate check results per destination platform. content: application/json: schema: type: object properties: Destination: type: array items: type: object properties: Platform_Name: type: string Surveys: type: array items: type: object properties: Flag: type: integer description: 1 if a duplicate was found, 0 if not. Survey_Number: type: string description: The processed survey number. Duplicate_Initial_UD: type: string description: >- Session ID where the previous record was found. Duplicate_Potential: type: string enum: - low - high Duplicate_Score: type: integer description: 0 or 100. Threat_Potential_Score: type: integer description: >- 1 (lowest threat) to 99 (highest threat), derived from internal evaluation signals. security: - ApiKeyAuth: [] components: securitySchemes: ApiKeyAuth: type: apiKey in: header name: x-api-key description: API key issued for the resdefio.com APIs. ```` This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.