# Checkout

In this chapter we are going to talk about the most common task: purchase of a product using [Stripe Checkout](https://stripe.com/docs/checkout). We assume you already read basic [get it started](/payum/get-it-started.md). Here we just show you modifications you have to put to the files shown there.

### Installation

The preferred way to install the library is using [composer](http://getcomposer.org/). Run composer require to add dependencies to *composer.json*:

```bash
php composer.phar require payum/stripe php-http/guzzle7-adapter
```

### config.php

We have to only add the gateway factory. All the rest remain the same:

```php
<?php
//config.php

use Payum\Core\PayumBuilder;
use Payum\Core\Payum;

/** @var Payum $payum */
$payum = (new PayumBuilder())
    ->addGateway('gatewayName', [
        'factory' => 'stripe_checkout',
        'publishable_key' => 'EDIT IT',
        'secret_key' => 'EDIT IT',
    ])

    ->getPayum()
;
```

### prepare.php

Here you have to modify a `gatewayName` value. Set it to `stripe_checkout`. The rest remain the same as described in basic [get it started](/payum/get-it-started.md) documentation.

***

### Supporting Payum

Payum is an MIT-licensed open source project with its ongoing development made possible entirely by the support of community and our customers. If you'd like to join them, please consider:

* [Become a sponsor](https://github.com/sponsors/Payum)


---

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