We're looking for a superb web development company to integrate Paypal with ActiveCollab's Invoicing Module.&nbsp; ActiveCollab already gives us the ability to invoice clients and send pdf invoices.&nbsp; We need to extend this functionality to receive paypal payments for invoices as well.<br/>When clients receive pdf documents we would like to add a paypal (pay now) button that will allow them to go to paypal and pay for the invoice in full.&nbsp; Once the invoice is paid in full, paypal calls back to ActiveCollab and marks the invoice as paid.&nbsp;<br/>The API documentation for ActiveCollab can be found in the link below.&nbsp; Thank you<br/>http://www.activecollab.com/docs/manuals/developers/api