This question already has an answer here:
I'm using the blockchain API to make a "send to many transaction". In the recipients I only put other people addresses, but somehow the API sends the remainder of my balance back to me.
I had 0.01 btc in my wallet. I sent 0.0000543 BTC to two different recipients, but somehow my whole balance got spent and my 0.0097914 BTC got sent back to me. I didn't ask for this.
EDIT: It also happens on a singular transaction:
I've inspected the API calls and they are correct. My address is no where to be seen in it.
Why is this happening?