Horizon is the client facing API server for the Stellar ecosystem. It acts as the interface between stellar-core and applications that want to access the Stellar network. It allows you to submit transactions to the network, check the status of accounts, subscribe to event streams, etc. See an overview of the Stellar ecosystem for more details.
Develop, Discover, Distribute
The Stellar Horizon API is a rich API which has multiple supported SDKs available from Stellar. You can incorporate them in your application and connect directly to the network using languages from C# to Scala. Or, you can make simple REST calls with curl or an API client like Postman. Set up streaming data endpoints and monitor ledgers in real-time, or create offers for tokens. The full capability of the API is at your fingertips.