Integrating PayPal Sandbox to Your Web Application - paypal

Question

I have a web application and I want to integrate the PayPal Sandox to it.
What are the steps to do so?

Answer 1

Since PayPal's integration guides can be unclear for beginners and other online tutorials can be too long for a simple checkout implementation, this Q&A aims to integrate the PayPal Sandbox to your web application quickly and easily. No external libraries or other downloads required.
STEP 1: Create a PayPal Sandbox Account. Follow this guide for test account creation.
STEP 2: Copy below sample HTML code for a basic Buy Now button (Single-Item Payment only):
<form action="https://www.sandbox.paypal.com/cgi-bin/webscr" method="post">
<!-- Identify your business so that you can collect the payments. -->
<input type="hidden" name="business" value="payments#yourbusiness.com">
<!-- Specify a Buy Now button. -->
<input type="hidden" name="cmd" value="_xclick">
<!-- Specify details about the item that buyers will purchase. -->
<input type="hidden" name="item_name" value="Your Product">
<input type="hidden" name="amount" value="25.00">
<input type="hidden" name="currency_code" value="USD">
<!-- Specify checkout options. -->
<input type="hidden" name="no_note" value="1">
<input type="hidden" name="no_shipping" value="1">
<input type="hidden" name="return" value="http://www.yoursite.com/paymentsuccessful.hmtl">
<input type="hidden" name="cancel_return" value="http://www.yoursite.com/paymentcancelled.hmtl">
<!-- Display the payment button. -->
<input type="image" name="submit" src="https://www.paypalobjects.com/en_US/i/btn/btn_buynow_LG.gif" alt="PayPal - The safer, easier way to pay online!">
<img alt="" border="0" width="1" height="1" src="https://www.paypalobjects.com/en_US/i/scr/pixel.gif">
</form>
form action - value is https://www.sandbox.paypal.com/cgi-bin/webscr, removing "sandbox"
means you are using the live PayPal website
business - does not have to be a real email, text displayed at the upper-left portion of the PayPal checkout page
cmd - _xclick means the button clicked was a Buy Now button
item_name - name of your product
amount - price of your product
currency_code - read here for supported values
no_note - do not prompt buyers to include a note with their payments (0 - false, 1 - true)
no_shipping - do not prompt buyers for a shipping address (0 - prompt but not required, 1 - do not prompt, 2 - prompt and require)
return - URL to which PayPal redirects the buyer's browser after they complete their payment
cancel_return - URL to which PayPal redirects the buyer's browser if they cancel checkout before completing their payment
Output:
References:
Testing Classic API Calls (recommended reading)
Single-Item Payments – Buy Now Buttons (more options available)
HTML Variables for Displaying PayPal Checkout Pages (more options available)