Is there a tool where I can send out +1000 transfers from MEW
I have the receiving wallets in excel, txt or csv file.
All should have the same amount
Speed don't matter. Prefer cheap gas.
Automatic
I don't think that such a tool exists. The only way I can see you can do it with MEW is to write a script which will make clicks instead of you and will send transcations one by one. Not sure if that's a good idea.
In order to send a batch of transactions automatically to multiple addresses you need a special smart contract with such a function.
