batch( requests )

Batch multiple HTTP requests together to issue them in parallel over multiple TCP connections. To set batch size, use the batch per host option.

Parameter	Type	Description
requests	array \| object	An array or object containing requests, in string or object form

Request definition

You have multiple ways to structure batch requests:

In an array of arrays
As an object or array of objects
As an array of URL strings

Defining batch requests as URL strings is a shortcut for GET requests. You can use this GET shortcut in objects—name a key and give it a URL value (refer to subsequent sections for example syntax).

Array and Object

You can define a request specified as an array or object with the following parameters.

Caution
When you define requests as an array, you must use a specific order of items. Note the Position column for the correct order.

Array position	Name	Type	Description
1	method	string	Mandatory. The HTTP method of the request. One of GET, POST, PUT, PATCH, DELETE, HEAD or OPTION.
2	url	string /HTTP URL	Mandatory. The URL to request.
3	body (optional)	string / object / ArrayBuffer	The body of the request if relevant. Can be set to `null` if not applicable but you want to set the last `params` argument.
4	params (optional)	object	Params like auth, custom headers and tags.

String

If you pass an array of string values, k6 automatically parses them into a batch of GET requests, where the target is the value of the strings.

Returns

Type	Description
object	The returned object contains Response objects. It is an array when users pass an array as `requests`, and is an ordinary object with string keys when named requests are used (see below).

Example with arrays

This example batches three URLs in arrays for parallel fetching:

import http from 'k6/http';
import { check } from 'k6';

export default function () {
  const responses = http.batch([
    ['GET', 'https://test.k6.io', null, { tags: { ctype: 'html' } }],
    ['GET', 'https://test.k6.io/style.css', null, { tags: { ctype: 'css' } }],
    ['GET', 'https://test.k6.io/images/logo.png', null, { tags: { ctype: 'images' } }],
  ]);
  check(responses[0], {
    'main page status was 200': (res) => res.status === 200,
  });
}

Example with request objects

This example uses objects to define a batch of POST requests (along with custom HTTP headers in a Params object to the request):

import http from 'k6/http';
import { check } from 'k6';

export default function () {
  const req1 = {
    method: 'GET',
    url: 'https://httpbin.test.k6.io/get',
  };
  const req2 = {
    method: 'GET',
    url: 'https://test.k6.io',
  };
  const req3 = {
    method: 'POST',
    url: 'https://httpbin.test.k6.io/post',
    body: {
      hello: 'world!',
    },
    params: {
      headers: { 'Content-Type': 'application/x-www-form-urlencoded' },
    },
  };
  const responses = http.batch([req1, req2, req3]);
  // httpbin.test.k6.io should return our POST data in the response body, so
  // we check the third response object to see that the POST worked.
  check(responses[2], {
    'form data OK': (res) => JSON.parse(res.body)['form']['hello'] == 'world!',
  });
}

Note
In the preceding example, req1 can happen before req2 or req3.

Example with array of strings

This example uses an array of URL strings to send a batch of GET requests.

import { check } from 'k6';
import http from 'k6/http';

export default function () {
  const responses = http.batch(['http://test.k6.io', 'http://test.k6.io/pi.php']);

  check(responses[0], {
    'main page 200': (res) => res.status === 200,
  });

  check(responses[1], {
    'pi page 200': (res) => res.status === 200,
    'pi page has right content': (res) => res.body === '3.14',
  });
}

Example object with named properties

Finally, you can also send in named requests by using an object instead of an array as the parameter to http.batch(). This example mixes string URLs and request objects.

import http from 'k6/http';
import { check } from 'k6';

export default function () {
  const requests = {
    'front page': 'https://k6.io',
    'features page': {
      method: 'GET',
      url: 'https://k6.io/features',
      params: { headers: { 'User-Agent': 'k6' } },
    },
  };
  const responses = http.batch(requests);
  // when accessing results, we use the name of the request as index
  // in order to find the corresponding Response object
  check(responses['front page'], {
    'front page status was 200': (res) => res.status === 200,
  });
}