1) Bitcoin needs time to transfer. How did you approve the transaction? Instantly in hoping it will go through or had the costumer to wait?
2) The problem with new Stellar addresses is, that they need to be "funded". Your sending wallet has to recognize if this address is empty to run the right function (it's not a normal transaction). Most of the wallets can't do that. They wouldn't be able to transfer any funds. Have you had problems with that?
As I understood it you have an initial address when you create a wallet for example on a Litecoin core node.
All addresses you create after this initial address are deterministic depending on their position. It's like you add just a number to the first address. But they are all unique otherwise sb. would see these addresses belong to one wallet.
And because they are unique your daemon has to watch or compare incoming transactions with every address you created to monitor payments. I might be wrong, but otherwise how does it work?
This would be a web3 solution. Most of the people are far away of using a wallet extension. I looked into it, the programming is much more challenging.
It depends on the exchange provider. I use Kraken and they provide an unique address for every costumer. But I read some Exchanges require the memo field especially for Stellar addresses.
If you use a memo field and there is an error the order won't be found in the system. In this case, you can write a script which sends the funds back to the address - fees. In this case you don't lose money and you don't need humans to interact. A more difficult problem would be if sb. sends a wrong amount. Then you have to interact with the costumer.
Yes, you're right. Polling is bad but the easiest solution. The best one would be to listen to incoming transactions and take action if a new one comes in. I'm going to use this solution if I continue the project.
I did this in my first project. As I said, UTXO blockchains are intended to work like that. But with every address you create your daemon has to look for changes there. Your wallet file can grow like crazy if you don't built some spam protection in your system.
For blockchains with the balance model you actually use only one address. There are solutions for Stellar to provide an unique address but this is not implemented yet.
The memo tag/field is the way to go. But as I said, it isn't widely implemented.
The random number is just a temporarily solution. The ideal one would be to use the memo field with an unique random string which contains all kind of characters. With this option you would have infinite payments.
The number solution can be improved if you search in the database for "free" numbers. I set the maximum payment time to 12 minutes. In this case, you can offer 100 payments per 12 minutes. I should update the article with this information.
Just remove the line numbers, every editor can mark in block mode today. Some snippets won't work without further code anyways.