Using the Stellar network, you can build mobile wallets, banking tools, smart devices that pay for themselves, and just about anything else you can dream up involving payments.
Horizon gives you a straightforward way to submit transactions, check accounts, and subscribe to events. Because it’s just HTTP, you can communicate with Horizon using your web browser, simple command line tools like cURL, or the Stellar SDK for your favorite programming language.
Behind the scenes, every Horizon server connects to Stellar Core, the backbone of the Stellar network. The Stellar Core software does the hard work of validating and agreeing with other instances of Core on the status of every transaction through the Stellar Consensus Protocol (SCP). The Stellar network itself is a collection of connected Stellar Cores run by various individuals and entities around the world. Some instances have a Horizon server you can communicate with, while others exist only to add reliability to the overall network.