Payment links


Before you start

You need a merchant account before starting the integration, if you don't have one then click here to head over to the site and complete the sign-up form

A payment link (f.ex. join link) allows you to send your customers to the Vendo payment pages to signup and/or pay for your product. It's one of the first things you need to configure to operate with Vendo.



Need S2S (server-to-server) integration instead of client redirect? Head over to the Gateway Payment API docs instead.


Using PHP?

Use the link-builder in Vendo's SDK for PHP!

Types of entry points

There are several types of entry points adapted to your different billing needs. We'll describe them briefly here - see the following pages for the complete documentation.

Standard Join link

This is the most common entry point. It's designed for most new end-user registration situations. The join pages gathers all necessary information to process an initial payment, end-user registration and setup of automatic recurring payments (rebills).

Instant Upgrade link

End-users who have signed up for a trial membership can instantly upgrade to a full (recurring) membership using this entry point.

One-click Join link

With this page, existing customers can sign up for an additional product or site. Since Vendo already has all the end-user's information, no fields need to be filled.

Update Payment Method link

Allows users to update their payment method on a given subscription. If successful, the new payment method will be used for all subsequent payments.

Change Offer link

Allows the customer to change their billing schedule (f.ex. from monthly to yearly or vice-versa).

Repurchase link

Allows the customer to repeat a subscription that expired.

How does it work?

You send your users to Vendo through a join link that you create on your site. The join link leads to the web page on the Vendo site where your customers' personal and payment information is collected for processing.

First, a customer follows a standard join link that prompts them to enter their data.

When the user submits valid payment data, Vendo makes an HTTP request to your CheckUser User Management API function. Once the payment is successfully processed, HTTP requests are made to your AddUser and Transaction functions on your User Management API. These HTTP requests are also called postbacks. Read more about postbacks here


Vendo link syntax

Each link to Vendo consists of a base URL followed by '?' and one or more name and value pairs of parameters that have to be passed to the entry point in order to make the pages work.

For example:,1002,1003

In the example above, is the standard join link base.
The part of the URL after the ? symbol is called the query string.
The query string in the example contains two name and value pairs of parameters:

Parameter nameParametere value

As you can see, they are separated from each with a & symbol.
You will use this symbol to append each next name and value pair to the query string.

Note: Make sure that all query-string parameters are properly URL-encoded when appended to the link. Use the correct helper functions for your programming language to ensure this, otherwise some links might not work correctly!

Each join link usually requires that some parameters are used, while others are optional.
In many cases, it is sufficient to provide a value for the site parameter.
For information about required and optional parameters, see the detailed documentation for each type of link.


Types of parameter values

Before you continue you might want to familiarize yourself with the explanation of the various data types and formats you will find in the following pages.