You might also use
coinbase API, as far as I know they do not require any fee for receive payment, but you might need KYC verification to avoid further problem. (Coinbase isn't recommended).
It's impossible nowadays to use Coinbase for anything without KYC verification. Also, Coinbase could end up blocking transactions similar to how BitPay has been blocking transactions recently. They're not going to do anything that their banking partner would force to cut ties with them, so they'll rather kick you out before any 'damage' is done.
While Coinbase doesn't charge any fees for their ecommerce services, you will have to pay a Bitcoin network fee to send the coins from your ecommerce account to your regular Coinbase account, and then pay another fee to convert to fiat, and then likely another fee to have the fiat be transferred to your bank account. In other words, their 'zero fee' service is just a gimmick.
I agree I'd definitely discourage using coinbase's API, even though they charge 0 fees, you'll need to show them everything for KYC, as well as there always being the possibility of your transactions being canceled/account locked, since they need to adhere to anything their banking partner tells them to do, otherwise it's over for them.
Coinbase has one of the worst spreads in the game, I would definitely not recommend using them, I think it's like over 5 percent with them. Use BTCpay, they have a great service, or electrum if your bothered to set it up, and if you aren't cashing out via an exchange, try to make your own ads on LBC, which gives you another way to profit off the spreads.