We offer two kinds of APIs for developers. The Bot API allows you to easily create programs that use Telegram messages for an interface. The Telegram API and TDLib allow you to build your own customized Telegram clients.
This API allows you to connect bots to our system. Telegram Bots are special accounts that do not require an additional phone number to set up. These accounts serve as an interface for code running somewhere on your server.
Bots can do anything from suggesting commands to fully replacing entire app interfaces. You can build bots that help users schedule meetings, manage shopping lists, or even play games.
This API allows you to build your own customized Telegram clients. It is 100% open for all developers who wish to create Telegram applications on our platform. Feel free to study the open source code of existing Telegram applications for examples of how things work here.
All Telegram client apps are open source. We welcome other developers to create Telegram apps for any platform. Our API is complete — everything that official Telegram clients can do, third-party clients can also do using our API.