Hi Oleg,
Thank you for contacting Syncfusion support.
We would like to let you know that, we have ensured our ejComponents in phoenix framework and it’s working fine. However, we have prepared a sample with some of our JavaScript controls. Please refer the below sample link.
Could you please check the above sample and get back to us if you faced any issue or need further assistance on this?
Regards,
Mohankumar R