## Documentation Index

Fetch the complete documentation index at: [/llms.txt](https://developers.criteo.com/llms.txt)

Use this file to discover all available pages before exploring further.

## API Endpoint
### GET /2026-01/retail-media/categories

### cURL

```bash
curl --request GET \
  --url https://api.criteo.com/2026-01/retail-media/categories \
  --header 'Authorization: Bearer <token>'
```

### Python

```python
import requests

url = "https://api.criteo.com/2026-01/retail-media/categories"

headers = {"Authorization": "Bearer <token>"}

response = requests.get(url, headers=headers)

print(response.text)
```

### JavaScript (Fetch API)

```javascript
const options = {method: 'GET', headers: {Authorization: 'Bearer <token>'}};

fetch('https://api.criteo.com/2026-01/retail-media/categories', options)
  .then(res => res.json())
  .then(res => console.log(res))
  .catch(err => console.error(err));
```

### PHP

```php
$curl = curl_init();

curl_setopt_array($curl, [
  CURLOPT_URL => "https://api.criteo.com/2026-01/retail-media/categories",
  CURLOPT_RETURNTRANSFER => true,
  CURLOPT_ENCODING => "",
  CURLOPT_MAXREDIRS => 10,
  CURLOPT_TIMEOUT => 30,
  CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
  CURLOPT_CUSTOMREQUEST => "GET",
  CURLOPT_HTTPHEADER => [
    "Authorization: Bearer <token>"
  ],
]);

$response = curl_exec($curl);
$err = curl_error($curl);

curl_close($curl);

if ($err) {
  echo "cURL Error #:" . $err;
} else {
  echo $response;
}
```

### Go

```go
package main

import (
	"fmt"
	"net/http"
	"io"
)

func main() {
	
	url := "https://api.criteo.com/2026-01/retail-media/categories"

req, _ := http.NewRequest("GET", url, nil)

req.Header.Add("Authorization", "Bearer <token>")

res, _ := http.DefaultClient.Do(req)

defer res.Body.Close()
	body, _ := io.ReadAll(res.Body)

fmt.Println(string(body))
}
```

### Unirest (Java)

```java
HttpResponse<String> response = Unirest.get("https://api.criteo.com/2026-01/retail-media/categories")
  .header("Authorization", "Bearer <token>")
  .asString();
```

### Ruby

```ruby
require 'uri'
require 'net/http'

url = URI("https://api.criteo.com/2026-01/retail-media/categories")

http = Net::HTTP.new(url.host, url.port)
http.use_ssl = true

request = Net::HTTP::Get.new(url)
request["Authorization"] = 'Bearer <token>'

response = http.request(request)
puts response.read_body
```

## Response Structure

### 200 - application/json

Categories found.

A top-level object that encapsulates a Criteo API response for several entities.

```json
{
  "data": [
    {
      "attributes": {
        "name": "<string>",
        "parentId": "<string>",
        "text": "<string>"
      },
      "id": "<string>",
      "type": "<string>"
    }
  ],
  "errors": [
    {
      "code": "<string>",
      "detail": "<string>",
      "instance": "<string>",
      "source": {},
      "stackTrace": "<string>",
      "title": "<string>",
      "traceId": "<string>",
      "traceIdentifier": "<string>"
    }
  ],
  "warnings": [
    {
      "code": "<string>",
      "detail": "<string>",
      "instance": "<string>",
      "source": {},
      "stackTrace": "<string>",
      "title": "<string>",
      "traceId": "<string>",
      "traceIdentifier": "<string>"
    }
  ]
}
```

### Authorization
- `Authorization`: string, required in header. The access token received from the authorization server in the OAuth 2.0 flow.

### Query Parameters
- `pageIndex`: integer, default:0, The start position in the overall list of matches. Must be zero or greater. Required range: `0 <= x <= 500`
- `pageSize`: integer, default:100, The maximum number of results to return with each call. Must be greater than zero. Required range: `1 <= x <= 100`
- `retailerId`: integer, The retailer id for which Categories fetched
- `textSubstring`: string, Query string to search across Categories.