Didn't really know where to post this, but since this software uses the API I decided to put it here.
I have been working on Migrating from OTRS to Freshdesk over the weekend and have wrote some command line PHP code that uses the Freshdesk API and a copy of an OTRS database to create tickets and add all ticket interactions as notes on the newly created Freshdesk.
The hardest part was dealing with the 1000 API calls per hour. I have an OTRS ticket database with ~81,000 items to migrate over.
Feel free to fork, pull, or contribute!
https://bitbucket.org/fastglass/otrs-to-freshdesk-migration/overview