# REST

The NLX Conversation REST API is the primary interface for building custom conversational experiences. It follows a standard RESTful pattern, allowing you to send user inputs (text or structured data) and receive a complete JSON response containing the AI app's reply.

### When to use this API

<table data-view="cards"><thead><tr><th></th><th></th></tr></thead><tbody><tr><td><i class="fa-gears">:gears:</i></td><td>Building custom web chat widgets or mobile app integrations</td></tr><tr><td><i class="fa-server">:server:</i></td><td>Server-to-server communication where streaming is not required</td></tr><tr><td><i class="fa-key-skeleton">:key-skeleton:</i></td><td>Integration with legacy systems that do not support Server-Sent Events (SSE)</td></tr></tbody></table>

### Authentication

This API uses a custom header for authentication. You must include your NLX API key in every request. &#x20;

| Header         | Value              |
| -------------- | ------------------ |
| `nlx-api-key`  | `YOUR_API_KEY`     |
| `Content-Type` | `application/json` |

The Application URL and API Key are located in the *API Delivery channel* setup.

<figure><img src="/files/HDYzUTwAdZ4sDAIPE37K" alt=""><figcaption></figcaption></figure>

Click *Setup instructions* to view Application URL and API Key.

<figure><img src="/files/132IgWmj19Zh9CQJXZV7" alt=""><figcaption></figcaption></figure>

### Base URL

All requests are made to the NLX App runtime. Note that the URL must include the language code (e.g., `-en-US`, `-es-MX`) appended to the channel key.

`https://apps.nlx.ai/c/{deploymentKey}/{channelKey}-{languageCode}`

* *deploymentKey*: The unique identifier for your specific AI app deployment
* *channelKey*: The identifier for the channel
* *languageCode*: The ISO language-country code (e.g., `en-US`)

The deploymentKey and channelKey values can be found below the Application URL and API Key in the Setup instructions dialog pictured in the [Authentication](#authentication) instructions above.  &#x20;

### Request structure

The API supports two main types of input:

1. *Unstructured*: Free-form text (natural language).
2. *Structured*: Explicit intent triggering or button clicks.

**Example: Sending a text message**

```bash
curl -X POST "https://apps.nlx.ai/c/YOUR_DEPLOYMENT_KEY/YOUR_CHANNEL_KEY-en-US" \
  -H "nlx-api-key: YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "request": {
      "unstructured": {
        "text": "Check my order status"
      }
    },
    "userId": "800f8dd7-4970-4d7e-aef4-4998e9843b0c",
    "conversationId": "9e8ad2b0-8cee-470c-89cf-93b8efde9ef0"
  }'
```

### Response format

The API returns a standard JSON object containing the AI app's messages, metadata, and updated session context.

```json
{
  "messages": [
    {
      "text": "Your order #5544 is out for delivery.",
      "type": "text",
      "messageId": "5aa637fc-e425-4f16-96fc-8ce17fa98520"
    }
  ],
  "conversationId": "9e8ad2b0-8cee-470c-89cf-93b8efde9ef0",
  "metadata": {
    "intentId": "OrderCheck",
    "isGenerative": true
  }
}
```


---

# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://docs.nlx.ai/platform/developers/conversation-api/rest.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.