---
title: OpenAPI Introduction
description: FastGPT OpenAPI Introduction
---

## Automated API Documentation

The automated API documentation covers all endpoints in the current version, regardless of whether they can be called via API Key.

All future endpoints will be auto-generated, with documentation continuously improved.

- [China Mainland API Documentation](https://cloud.fastgpt.cn/openapi)
- [International API Documentation](https://cloud.fastgpt.io/openapi)

## Usage Guide

FastGPT OpenAPI lets you authenticate with an API Key to access FastGPT services and resources -- such as calling app chat endpoints, uploading knowledge base data, search testing, and more. For compatibility and security reasons, not all endpoints support API Key access.

## How to Find Your BaseURL

**Note: BaseURL is not an endpoint address -- it's the root URL for all endpoints. Requesting the BaseURL directly won't work.**

![](/imgs/fastgpt-api-baseurl.png)

## How to Get an API Key

FastGPT has **2 types** of API Keys: a global key (cannot directly call app chat) and an app-specific key that includes an AppId (can directly call app chat).

We recommend using `app-specific keys` only for app or chat-related endpoints, and `global keys` for everything else.

|        Global Key               |           App-Specific Key            |
| --------------------- | --------------------- |
| ![](/imgs/fastgpt-api2.jpg) | ![](/imgs/fastgpt-api1.jpg) |


## Basic Configuration

In OpenAPI, all endpoints authenticate via Header.Authorization.

```
baseUrl: "http://localhost:3000/api"
headers: {
    Authorization: "Bearer {{apikey}}"
}
```

**Example: Start an App Chat**

```sh
curl --location --request POST 'http://localhost:3000/api/v1/chat/completions' \
--header 'Authorization: Bearer fastgpt-xxxxxx' \
--header 'Content-Type: application/json' \
--data-raw '{
    "chatId": "111",
    "stream": false,
    "detail": false,
    "messages": [
        {
            "content": "Who is the director",
            "role": "user"
        }
    ]
}'
```

## Custom User ID

Since `v4.8.13`, you can pass a custom user ID that will be saved in the chat history.

```sh
curl --location --request POST 'http://localhost:3000/api/v1/chat/completions' \
--header 'Authorization: Bearer fastgpt-xxxxxx' \
--header 'Content-Type: application/json' \
--data-raw '{
    "chatId": "111",
    "stream": false,
    "detail": false,
    "messages": [
        {
            "content": "Who is the director",
            "role": "user"
        }
    ],
    "customUid": "xxxxxx"
}'
```

In the chat history, this record's user will be displayed as `xxxxxx`.