That's exactly how it works
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Is there any way to check user's address balance via API? or this can be done only through parsing "faucetbox.com/en/check/address" page?
For now that's only possible via parsing the page. Would you want to display it to user after sending him coins? If so, then I think we can implement something like this in the API, but not in the next 2 weeks or so (we have hands full of work).
If I delay my payments for doge for example it affects on all currencies? And if yes could you do delays for each currency separately?