Ethereum Testing – How to Automate End-to-End Testing for Ethereum DApps with MetaMask

Yes.

There are two approaches to consider

You can interact with Web3 on the client side and JavaScript

• The user uses Mist or Parity browser or MetaMask and are connected to their own Ethereum node

• All interaction with the user wallet (private keys) happens on the client side, in JavaScript

• This is safe because the user does not need to give the control of his or her private keys to the service provider

• You can still render pages in whatever backend programming language you wish, but currently web browsers do not support other scripting languages besides JavaScript

Here is a tutorial to build a frontend.

Old fashioned way

• You can interact with Ethereum node on the server-side as you would interact on the client side

• Web3 has standardish implementation for all programming languages (except maybe not PHP). Web3.py allows interaction from Python, you can use Web3.js in Node.

• These libraries speak to Ethereum node running locally on the server side over JSON-RPC

• You might need to do accounting for your users, a non-trivial task that I would not recommend non-experienced programmer to try

Also see Executing a Smart Contract in a Mobile App

In Ethereum, the closest you can get to a fiat currency is to use DAI, a decentralised stable coin. It was created by MakerDao and, despite being at the beginning, they are doing a great job. DAI is 10x better than other centralised solutions which merely peg the token to a USD bank account.

To address your question, there is no way around the problem other than:

1. Integrating with a third-party exchange and ask customers to sign-up there (KYC will most likely apply)
2. Depending on the nature of your business (whether you allows users to keep money on your website), you may be able to exchange their money to ETH, on demand, by connecting to a decentralised exchange. To preclude volatility risks, you could keep the business' funds in DAI.