# Messages In the Acki NAcki blockchain, a **message** is the fundamental unit of interaction between accounts (contracts). All actions, state changes, and logic execution within accounts are triggered by messages. ### Message types There are three types of messages in Acki Nacki: * External incoming: sent from outside the blockchain → received by a smart contract * Internal: sent from a smart contract → received by a smart contract * External outgoing: sent from a smart contract → received outside the blockchain You can learn more at the following link: --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://docs.ackinacki.com/for-developers/messages.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.