Hello, I have a Wordpress site in which end users can sign up to create their own wordpress site. Once a user signs up, he chooses a plan, and is accordingly billed for it. Billing is also handled by a wordpress plugin. Separately, there is a billing platform called SaaSy-- this platform handles every aspect of billing. What I want is that instead of the billing being handled internally by the wordpress plugin, the user is redirected to the SaaSy website, he makes the payment there, and on successful payment, he is sent back to wordpress -and rest of work done by the wordpress plugin is done by it as usual-- only the payment portion is handled by SaaSy. In addition to simple redirection (between Wordpress and SaaSy at the billing stage)-- some simple programming is required to communicate plan changes and wordpress utilisation, between Wordpress and SaaSy. These are described below-- -- Send notification to WP from SaaSy when a user signs up for a new account/ closes his account. -- The plan enforcement (like space limits/ plugins available) will still remain with WP-- corresp plans ( with 1:1 mapping for each WP plan) will need to be created at SaaSy. -- When a user reaches his plan limits in Wordpress, Wordpress sends an email and admin notice to him asking him to upgrade-- this has to be slightly modified so that appropriate link to his SaaSy account is also added to the email+notification. -- When user wants to upgrade/downgrade his wordpress plan, normally he is asked to make payment directly in the wordpress site-- change this so that he is sent to SaaSy instead. And once payment/refund is successful-send him back to wordpress- now allow the wordpress plugin to do its work of upgrading/downgrading his wordpress plan. -- there should be a script to sync plans between wordpress and SaaSy. So that when I create a new plan in my Wordpress site-- a plan corresp. to this WP plan is created in my SaaSy account as well. Similarly if I edit/delete any such plans in WP corresp, changes have to be made to the appropriate plan in SaaSy. The above is all very simple PHP programming