Adding a Lead ID token to a URL in an outbound e-mail.

[Anonymous]

About 4-5 years ago, in another lifetime, I remember adding a token to URLs in outbound Marketo emails that would append the LeadID to the URL, so that when the recipient clicked on the URL, it would send their Lead ID back to Marketo, to help ensure we could identifying the recipient, and pre-fill, or prog. profile the form. 

For example, if the Marketo cookie was deleted, this would identify the lead record.

For the life of me, I cannot find in the resource files how to do this again.

Is it just buried in &mkt_tok now?

[Josh_Hill13]

Generally you should not show this id in the URL as it could be a security risk.

Is pre-fill enabled on the form or page? I am unsure if it would necessarily display this by default without a cookie or mkt_tok

[Anonymous]

I've rediscovered the answer to this, but I remembered that adding this token would pre-fill the form with the info on file from the lead. In my case now, it's not doing so.  Is it supposed to? Or is there a form setting somewhere I need to tweak re: pre-fill.

&LeadID={{Lead.ID}}