they do require proof of Developer
they have not yet added any altcoins
but are accepting requests
https://1ex.trade/index.php
https://1ex.trade/about.php
https://1ex.trade/our-security.php
https://1ex.trade/fee-schedule.php
i've done a PoD, with cryptoasian. feel free to request DOGED there..
not sure if they require there own proof
but i submitted request
response from 1ex.trade
"Sorry but we don't accept PoD from other sources. We carry out our own checks and don't accept 3rd party verification's
We will have a look at the coin but the developer must get verified from us or our partner bank."
Kind Regards
1Ex Support Team"