Question about Pro Version

Hello,

I purchased the pro version so that I can use the API Post GET / REQUEST. I am looking to post the lead data to an external URL. However I’m a bit confused about the ‘Tags mapping’ section.

I see there is an opportunity to enter an ‘API key’ for each field – I was given just 1 post key, so I entered the same post key into all of these fields. Is that the correct way to set it up?

Also what should I enter into the ‘Function’ dropdown. I see there are 4 options. Would you mind telling me what these options mean?

md5
base64_encode
utf8_encode
urlencode

Thanks,
Ethan