> ## 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.

# Research Defender Overview

> What Research Defender does, the SEARCH, REVIEW, and PREDUPE products, and how they fit into your survey flow.

*This page introduces the Research Defender product suite and how each product protects survey data quality.*

<Note>
  This documentation covers **SEARCH**, **REVIEW**, and **PREDUPE**. ACTIVITY and VERIFY are hosted on a separate domain (`resdefio.com`) and are documented separately.
</Note>

***

## 1. What is Research Defender?

Research Defender protects survey data quality by identifying fraudulent, duplicate, and low-effort respondents before and during a survey. It combines digital fingerprinting, duplication detection, and open-end text analysis into a set of API products you call as respondents move through your survey flow.

***

## 2. The Products

| Product     | What It Does                                                                                                                                                            |
| ----------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| **SEARCH**  | Industry-leading digital fingerprinting with bot and click-farm detection. Returns a threat potential score, duplication scoring, and geolocation checks.               |
| **REVIEW**  | Text analysis of open-ended survey responses — copy/paste, profanity, engagement, language, and LLM detection.                                                          |
| **PREDUPE** | An add-on to the SEARCH call that identifies when a respondent has already attempted a survey while still in the supplier's environment, increasing conversion and EPC. |

<CardGroup cols={2}>
  <Card title="SEARCH" icon="fingerprint" href="/research-defender/guides/01-search">
    Fingerprinting, bot/click-farm detection, and duplication scoring.
  </Card>

  <Card title="PREDUPE" icon="users-slash" href="/research-defender/guides/02-predupe">
    Detect prior survey attempts before the respondent enters.
  </Card>

  <Card title="REVIEW" icon="comment-dots" href="/research-defender/guides/03-review">
    Open-end text quality analysis.
  </Card>

  <Card title="Platform Guides" icon="puzzle-piece" href="/research-defender/guides/04-platform-guides">
    Platform-specific setup for Qualtrics, Forsta, Alchemer, and more.
  </Card>
</CardGroup>

***

## 3. How It Fits Your Survey Flow

1. **At entry**, call **SEARCH** (optionally with **PREDUPE** parameters) to fingerprint the respondent, detect duplicates, and check for fraud signals before they enter the survey.
2. **During the survey**, use **REVIEW** to analyze open-ended responses for copy/paste, profanity, low engagement, and LLM-generated text.
3. **Apply your term logic** based on the scores returned. Research Defender publishes [recommended term logic](https://docs.google.com/document/d/1B5bJScX0kQzzCsrWqzgF46rV44ciYiEu16bgZutoK7w/edit?usp=sharing) for each product.

***

## 4. Protecting Your Integration

Nefarious respondents may attempt API suppression or link manipulation to bypass security checks. Research Defender offers two options to protect against this:

* **V3 server-to-server tokens (GETTOKEN)** — hide sensitive scores behind a server-side response.
* **V4 Hashed Validation** — validate request inputs and outputs with a SHA-256 value signed by your private key.

See [Security Options](https://docs.repdata.com/research-defender/overview/02-security-options) for details.

***

## 5. Next Steps

<CardGroup cols={2}>
  <Card title="Environments & Authentication" icon="key" href="/research-defender/overview/01-environments-and-authentication">
    Base URLs and how publishable and private keys are used.
  </Card>

  <Card title="API Reference" icon="code" href="/research-defender/endpoints/get-api-v4-respondents-search-publishable_key">
    Parameters, response schemas, and a live playground for every endpoint.
  </Card>
</CardGroup>