Unfortunately the Crello integration cannot happen at this time.
We contacted them for API access, and this is their response:
“Thank you for writing in.
As of now, we are in the process of enhancing our API solution and currently do not offer new API keys.
Feel free to reach out regarding this in 3-4 months and the new API solution will probably be ready by this time.
Should you have any other questions, feel free to get in touch -we are always happy to help!”