Thank you for your feedback!
Can we see source code for Altos? Is it open or closed source code?
It is closed source for now. We may be opening it and posting on GitHub in the future. The reason for the closed source is we don't hold any funds in the contract, so no risk or losing them. All funds are passed through immediately to the merchant. There's no need, for now at least, to audit the source code.
I am not even sure you are supporting Bitcoin for payments.
We do not accept bitcoin at this time. Our focus is mainly stablecoins on EVM-compatible blockchains. But, bitcoin and other non-EVM compatible coins are on the roadmap.
If merchant need to open an account at your website, that means your payment processor is centralized.
Actually, the website only contains the integration instructions. It's not necessary to open an account there.
There are much better open source payments processors like Btcpayserver, CypherpunkPay and few others.
Sure, for people who want to run their own Linux daemon and only accept bitcoin