A - teloxide-core

As you may, or may not have noticed, teloxide consists of two crates -- teloxide (main crate) and teloxide-core (core crate). Main crate depends on the core crate and reexports everything from it.

Core crate contains

• Telegram types (like Update, Message, Chat)
• Everything related to making requests (payloads, requests, requesters)
• Bot adaptors (like AutoSend, ErasedRequester)
• Errors

i.e. everything that is related to the Telegram Bot API.

The main crate on the other hand contains

• Reexports of everything from core crate
• repls
• Dispatching systems (that allow you to process updates)
• Update listeners
• Utils to work with formatting
• Utils to work with commands

i.e. the more high level stuff built on top of the Telegram Bot API.

Normally you want to use teloxide, but in rare cases when you don't need any high-level APIs, you may use teloxide-core directly.