- The SDK used for defining behavior of your chat bot. Implements the bot framework protocol.
- Currently in v4, released in September of last year
- Has stable releases for C# and JavaScript/TypeScript. Has preview releases for Java and Python.
- Deploys to any app server, same as any HTTP app
- Persistent state via Azure Storage, Cosmos DB, or custom storage implementation
- Cognitive services for bot intelligence, such as language understanding models, QnA builder, Spell Check, translation, etc.
The SDK versions separately from the underlying protocol used to communicate with the Bot Service. The v4 SDK simply uses a different set of coding patterns from v3, but still implements the same protocol. Bots built with v3 are still compatible with Bot Service.