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

# Custom Headers and Cookies

Use the `headers` parameter to send custom HTTP headers and cookies with your request. This is useful when the target website requires specific headers (like `User-Agent`, `Referer`, or `Cookie`) to return the expected content.

<Warning>
  Use carefully with anti-bot protected sites - invalid or mismatched headers may cause blocks
</Warning>

<Warning>
  If you override critical headers (e.g. `Accept-Encoding`), it may impact response parsing
</Warning>

## When to Use

* Bypass geo or device-based content blocks by setting a `User-Agent`
* Simulate logged-in sessions using `Cookie` headers
* Add custom `Authorization` headers to access gated content
* Force-language or locale-specific versions of a page (e.g. `Accept-Language: fr-FR`)

## Format

The `headers` parameter is a JSON object with header names and values.

```json theme={null}
{
  "User-Agent": "Mozilla/5.0 (Windows NT 10.0; Win64; x64)",
  "Referer": "https://example.com/",
  "Cookie": "session_id=abc123"
}
```

## Example Request

<CodeGroup>
  ```bash cURL theme={null}
  curl --request POST \
    --url 'https://api.hasdata.com/scrape/web' \
    --header 'Content-Type: application/json' \
    --header 'x-api-key: <your-api-key>' \
    --data '{"url":"https://example.com/dashboard","headers":{"User-Agent":"Mozilla/5.0","Cookie":"auth_token=xyz789"},"outputFormat":["html"]}'
  ```

  ```bash HasData CLI theme={null}
  hasdata web-scraping \
    --url 'https://example.com/dashboard' \
    --headers-json '{"User-Agent":"Mozilla/5.0","Cookie":"auth_token=xyz789"}' \
    --output-format html
  ```

  ```javascript Node.js theme={null}
  const axios = require('axios').default;

  const options = {
    method: 'POST',
    url: 'https://api.hasdata.com/scrape/web',
    headers: {'Content-Type': 'application/json', 'x-api-key': '<your-api-key>'},
    data: {
      url: 'https://example.com/dashboard',
      headers: {'User-Agent': 'Mozilla/5.0', Cookie: 'auth_token=xyz789'},
      outputFormat: ['html']
    }
  };

  try {
    const { data } = await axios.request(options);
    console.log(data);
  } catch (error) {
    console.error(error);
  }
  ```

  ```python Python theme={null}
  import requests

  url = "https://api.hasdata.com/scrape/web"

  payload = {
      "url": "https://example.com/dashboard",
      "headers": {
          "User-Agent": "Mozilla/5.0",
          "Cookie": "auth_token=xyz789"
      },
      "outputFormat": ["html"]
  }
  headers = {
      "Content-Type": "application/json",
      "x-api-key": "<your-api-key>"
  }

  response = requests.post(url, json=payload, headers=headers)

  print(response.json())
  ```

  ```php PHP theme={null}
  <?php

  $payload = [
      "url" => "https://example.com/dashboard",
      "headers" => ["User-Agent" => "Mozilla/5.0", "Cookie" => "auth_token=xyz789"],
      "outputFormat" => ["html"],
  ];

  $curl = curl_init();

  curl_setopt_array($curl, [
    CURLOPT_URL => "https://api.hasdata.com/scrape/web",
    CURLOPT_RETURNTRANSFER => true,
    CURLOPT_CUSTOMREQUEST => "POST",
    CURLOPT_POSTFIELDS => json_encode($payload),
    CURLOPT_HTTPHEADER => [
      "Content-Type: application/json",
      "x-api-key: <your-api-key>",
    ],
  ]);

  $response = curl_exec($curl);
  curl_close($curl);

  echo $response;
  ```

  ```java Java theme={null}
  OkHttpClient client = new OkHttpClient();

  MediaType mediaType = MediaType.parse("application/json");
  String json = """
    {
      "url": "https://example.com/dashboard",
      "headers": {
        "User-Agent": "Mozilla/5.0",
        "Cookie": "auth_token=xyz789"
      },
      "outputFormat": [
        "html"
      ]
    }
  """;
  RequestBody requestBody = RequestBody.create(json, mediaType);

  Request request = new Request.Builder()
    .url("https://api.hasdata.com/scrape/web")
    .post(requestBody)
    .addHeader("Content-Type", "application/json")
    .addHeader("x-api-key", "<your-api-key>")
    .build();

  Response response = client.newCall(request).execute();
  ```

  ```csharp C# theme={null}
  using System.Net.Http;
  using System.Text;

  var client = new HttpClient();

  var json = """
  {
    "url": "https://example.com/dashboard",
    "headers": {
      "User-Agent": "Mozilla/5.0",
      "Cookie": "auth_token=xyz789"
    },
    "outputFormat": [
      "html"
    ]
  }
  """;
  var content = new StringContent(json, Encoding.UTF8, "application/json");

  var request = new HttpRequestMessage(new HttpMethod("POST"), "https://api.hasdata.com/scrape/web")
  {
      Content = content,
  };
  request.Headers.Add("x-api-key", "<your-api-key>");

  using var response = await client.SendAsync(request);
  response.EnsureSuccessStatusCode();
  var body = await response.Content.ReadAsStringAsync();
  Console.WriteLine(body);
  ```

  ```ruby Ruby theme={null}
  require 'net/http'
  require 'uri'
  require 'json'

  uri = URI("https://api.hasdata.com/scrape/web")
  payload = {
    "url" => "https://example.com/dashboard",
    "headers" => {"User-Agent" => "Mozilla/5.0", "Cookie" => "auth_token=xyz789"},
    "outputFormat" => ["html"],
  }

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

  request = Net::HTTP::Post.new(uri)
  request["Content-Type"] = 'application/json'
  request["x-api-key"] = '<your-api-key>'
  request.body = payload.to_json

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

  ```rust Rust theme={null}
  use reqwest::blocking::Client;
  use serde_json::json;

  fn main() -> Result<(), Box<dyn std::error::Error>> {
      let client = Client::new();
      let payload = json!({
          "url": "https://example.com/dashboard",
          "headers": {
              "User-Agent": "Mozilla/5.0",
              "Cookie": "auth_token=xyz789"
          },
          "outputFormat": [
              "html"
          ]
      });
      let res = client
          .post("https://api.hasdata.com/scrape/web")
          .header("Content-Type", "application/json")
          .header("x-api-key", "<your-api-key>")
          .json(&payload)
          .send()?
          .text()?;
      println!("{}", res);
      Ok(())
  }
  ```

  ```go Go theme={null}
  package main

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

  func main() {
  	payload := []byte(`{
    "url": "https://example.com/dashboard",
    "headers": {
      "User-Agent": "Mozilla/5.0",
      "Cookie": "auth_token=xyz789"
    },
    "outputFormat": [
      "html"
    ]
  }`)

  	req, _ := http.NewRequest("POST", "https://api.hasdata.com/scrape/web", bytes.NewBuffer(payload))
  	req.Header.Add("Content-Type", "application/json")
  	req.Header.Add("x-api-key", "<your-api-key>")

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

  	responseBody, _ := io.ReadAll(res.Body)
  	fmt.Println(string(responseBody))
  }
  ```
</CodeGroup>

## Notes

* All custom headers are passed as-is to the target page
* To send cookies, use the `Cookie` header — multiple cookies should be in standard format: `"key=value; key2=value2"`