Neil_Robertson6

REST is always the preferred choice now. SOAP is a legacy deployment. I would also recommend 100% that you always use JSON as payload and response and XML is not well supported in Marketo - especially when it comes to element attributes.

What Marketo can sync and see is entirely dependent on sharing rules and the OWD of SFDC. Note as well though that depending on your SFDC database size that a sync can take anywhere between 1 hour to 2 weeks (seriously) to synchronize fully.

Thanks Sandford - Great JS but only downside I can see is the size limit of a small 64k!

Change #END to be #end (note the syntax highlighting which is showing you it is not correct)

What capabilities do you have in your CRM - i.e. DemandTools/Dupeblocker?

That is the way to do it but I would, if possible, see if you can encrypt/decrypt the string and not pass emails in the URL as plain text - otherwise your database could be open for rogue unsubscribes.

You may have to anagrammatically work this out using a field to hold a data value change - as it will need to be a trigger. Be wary of too many webhook calls though as they can slow down your instance / processes if you have a lotN

Yep, a tool / service such as Zapier can provide the ability to tweet should you need to.