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

# Quick Start

> Quickly learn how to use the Cregis Developer API

## Download the Cregis PC Client

Visit the download link [https://www.cregis.com/download](https://www.cregis.com/download)

Select your operating system to download the corresponding Cregis installation package. The package sizes are approximately:

* **Mac**: 148M
* **Windows**: 105M

<p align="center">
  <img src="https://mintcdn.com/eg/eb7TqKKrnkBKfAwg/images/cregis-desktop.png?fit=max&auto=format&n=eb7TqKKrnkBKfAwg&q=85&s=6cd496c43cfe7d06cdcb8d30419d1371" alt="Cregis Desktop App" width="auto" height="auto" data-path="images/cregis-desktop.png" />
</p>

## Register an Account and Log In

For details, refer to [Registration and Login](https://support.cregis.com/getting-started/publish-your-docs)

1. Register a Cregis account
2. Bind Google Authenticator
3. Log in to your Cregis account

## Generate API Key

1. Open the Cregis App
2. In "Wallet", create a wallet named "my-wallet"

<p align="center">
  <img src="https://mintcdn.com/eg/eb7TqKKrnkBKfAwg/images/frontpage-wallet.jpg?fit=max&auto=format&n=eb7TqKKrnkBKfAwg&q=85&s=fd96517e402a028624f16f3302cff81b" alt="frontpage wallet" width="auto" height="auto" data-path="images/frontpage-wallet.jpg" />
</p>

<p align="center">
  <img src="https://mintcdn.com/eg/eb7TqKKrnkBKfAwg/images/create-wallet.png?fit=max&auto=format&n=eb7TqKKrnkBKfAwg&q=85&s=31628dec9d41aaba41e0eef852473d85" alt="cregis wallet" width="auto" height="auto" data-path="images/create-wallet.png" />
</p>

3. Create Project

\-- [*API*](https://support.cregis.com/api/api-manual/creation)

\-- [*Payment Engine*](https://support.cregis.com/payment-engine/creation)

Please keep your **API Key**, **Gateway Server**, and **Project NO.** safe and do not share them with others.

## Test API Key

1. [Choose the SDK you need](/sdk-tool/sdk): Java, Go, PHP, C#

2. Prepare the 3 key pieces of information required by the SDK:
   API Key, Gateway Server, Project NO.

3. [Java Test Case](https://github.com/0xcregis/cregis-java-sdk/blob/master/cregis-sdk-core/src/test/java/com/cregis/core/HutoolClientTest.java)

For details on constructing HTTP Requests, refer to [Request Description](/api-reference/request)