We’re working through a solution now with a third-party vendor to create custom code. Our use case is that we have a text platform integration that creates contacts with only a phone number - the majority are already in our database and need to be merged with an existing contact.
Our biggest challenge thus far has been phone number formatting. Luckily our contacts are all US-based phone numbers but if you have any numbers that are in different countries this is a challenge as well. We’re working on code that formats the phone numbers but it’s been tricky to make everything match up exactly so that they’ll merge since there are so many ways they can show up…with and without parenthesis, with and without country codes, with and without a + before country code, with and without spaces, etc.