Excerpt (in the context of Ethereum, a smart contract platform):
> A DApp has its backend code running on a decentralized peer-to-peer network. Contrast this with an app where the backend code is running on centralized servers.
> A DApp can have frontend code and user interfaces written in any language (just like an app) that can make calls to its backend. Furthermore, its frontend can be hosted on decentralized storage such as Swarm or IPFS.
> If an app=frontend+server, since Ethereum contracts are code that runs on the global Ethereum decentralized peer-to-peer network, then: DApp = frontend + contracts
How does the web3 or whatever js running in your web browser know what gateway to use to interface with the blockchain? What if that gateway goes down? How does it or any ETH or Bittorent node bootstrap in general?
The web3.js file doesn't pick your gateway. MetaMask uses a default gateway from Infura, but you can switch to another such as Cloudflare's gateway or a local node.
Excerpt (in the context of Ethereum, a smart contract platform):
> A DApp has its backend code running on a decentralized peer-to-peer network. Contrast this with an app where the backend code is running on centralized servers.
> A DApp can have frontend code and user interfaces written in any language (just like an app) that can make calls to its backend. Furthermore, its frontend can be hosted on decentralized storage such as Swarm or IPFS.
> If an app=frontend+server, since Ethereum contracts are code that runs on the global Ethereum decentralized peer-to-peer network, then: DApp = frontend + contracts