> ## Documentation Index
> Fetch the complete documentation index at: https://developers.respondent.io/llms.txt
> Use this file to discover all available pages before exploring further.

# Introduction

> Get started with the Respondent Partner API

Respondent's API gives your development team the tools to deliver seamless, high-quality participant recruitment—right from your own platform. By integrating our API, you can give your researchers access to Respondent's deeply profiled, highly qualified participant pool without ever leaving your environment.

<CardGroup cols={2}>
  <Card title="Create projects" icon="folder-plus">
    Set up research projects and screeners programmatically with full targeting control.
  </Card>

  <Card title="Manage participants" icon="users">
    Retrieve profiles, qualify, invite, and track participant status in real-time.
  </Card>

  <Card title="Send messages" icon="paper-plane">
    Communicate with participants throughout the study lifecycle via the messaging API.
  </Card>

  <Card title="Monitor via webhooks" icon="bell">
    Receive real-time notifications for participant status changes and project events.
  </Card>
</CardGroup>

Your developers can integrate these endpoints to build custom UI for project creation and participant management and embed Respondent workflows directly into your platform. Whether you're building new tools or enhancing existing ones, the Respondent API enables you to streamline study setup and deliver exceptional participant experiences.

To begin, you'll need a Client ID and Client Secret. Visit our [Quickstart Guide](/docs/Getting-started/quickstart) to learn the steps to receiving credentials and start integrating.

## Authentication

All API requests require two headers: `x-api-key` (your Client ID) and `x-api-secret` (your Client Secret).

```bash theme={null}
curl --request GET \
  --url 'https://api-staging.respondent.io/v1/skills?query=comp' \
  --header 'x-api-key: YOUR_API_KEY' \
  --header 'x-api-secret: YOUR_API_SECRET'
```

## Base URLs

| Environment    | Base URL                            |
| -------------- | ----------------------------------- |
| **Staging**    | `https://api-staging.respondent.io` |
| **Production** | `https://api.respondent.io`         |

<Note>
  Build and test your integration in staging first, then switch to production when ready. See [Staging vs Production](/reference/staging-vs-production) for important differences.
</Note>

## Rate limiting

To ensure stability and fair usage across clients, our API enforces the following rate limits:

| Environment | Requests per Second | Burst Capacity | Daily Quota            |
| ----------- | ------------------- | -------------- | ---------------------- |
| Production  | 250 RPS             | 500 requests   | 1,000,000 requests/day |
| Staging     | 50 RPS              | 100 requests   | 200,000 requests/day   |