Integration partners: User agent strings

When Mollie merchants contact our support department, knowing which integration the merchant uses is incredibly helpful in offering them the fastest and best possible support. Having this information helps us understand which features are supported by your integration, and pinpoint any issues.

The Mollie API gathers information about your plugin or platform with every API call. You can pass this information to Mollie by amending the User-Agent header with what we call “version strings”.

All our API clients expose convenient methods to supply user agent strings.


The basic syntax for a user agent string is Name/x.x.x.

This syntax follows common user agent components you may be familiar with such as Mozilla/5.0 or Googlebot/2.1.

Depending on your integration, you may want to supply two or more user agent strings, e.g. one for your plugin and one for the platform it runs on.

Make sure that the name you choose clearly describes your integration, and that you do not change the name over time.


  • Mollie module for Magento 2: MollieMagento2/0.9.9 Magento/2.1.5
  • Mollie extension for OpenCart: MollieOpenCart/8.4.0 OpenCart/
  • Mollie plugin for WooCommerce on WordPress: MollieWoo/5.0.7 WooCommerce/3.6.4 WordPress/5.2.3

Option A: Using an API client

Our API clients expose convenient methods for supplying user agent strings.

The code examples below illustrate how the Mollie plugin (v0.9.9) for Magento 2 (v2.1.5) would pass user agent strings.

curl -X POST \
   -H "Authorization: Bearer test_dHar4XY7LxsDOtmnkVtjNVWXLSlXsM" \
   -A "MollieMagento2/0.9.9 Magento/2.1.5" \
   -d '...'
$mollie = new \Mollie\Api\MollieApiClient();

from mollie.api.client import Client

mollie_client = Client()

mollie_client.set_user_agent_component('MollieMagento2', 0.9.9)
mollie_client.set_user_agent_component('Magento', 2.1.5)
Mollie::Client.configure do |config|
  config.api_key = 'test_dHar4XY7LxsDOtmnkVtjNVWXLSlXsM'

const { createMollieClient } = require('@mollie/api-client');

const mollieClient = createMollieClient({
  apiKey: 'test_dHar4XY7LxsDOtmnkVtjNVWXLSlXsM',
  versionStrings: ['MollieMagento2/0.9.9', 'Magento/2.1.5']

If you are using Laravel, check out the addVersionString()method here.

Option B: Using the native REST API

We always recommend using one of our API clients for a solid foundation and faster development.

If, however, you are integrating our native REST API, use your HTTP client of choice to append integration data to the User-Agent header. Refer to the syntax and cURL examples above and be sure to separate multiple user agent strings with spaces.