# Understanding Internal vs. External MQTT Brokers on Datacake ## Introduction Datacake offers two primary MQTT broker options for users to manage and ingest data: the internal MQTT broker (`mqtt.datacake.co`) and external MQTT brokers through a third-party MQTT bridge. This document details the features, limitations, and usage of both options to help users select the appropriate broker based on their needs. ## Internal MQTT Broker ### Overview The internal MQTT broker is tightly integrated with the Datacake backend and is primarily used for real-time communication between the backend and dashboards. It allows direct data ingestion into Datacake's database and supports user authentication. ### Features * **Real-time Communication:** Enables real-time updates between Datacake's backend and dashboards. * **Direct Database Integration:** Ingests data directly into Datacake's database fields. * **Fixed Topic Structure:** Utilizes a fixed topic structure for consistency and security. * **User Authentication:** Requires user authentication for publishing and subscribing. ### Topic Structure #### **Subscribe** To receive messages via MQTT when readings arrive in the Datacake Cloud, subscribe using the following structure: ```plaintext dtck/// ``` Messages are published whenever there is a change to the corresponding database field. #### **Publish** To upload data into the Datacake Cloud and a specific device, publish to: ```plaintext dtck-pub/// ``` **Note:** Always use the prefix `dtck-pub/` to import measured values. ### Topic Elements * **Product-Slug (``):** Specifies the product path. This is useful for managing multiple devices of the same product type. The specification can be found in the metadata section of the device view. * **Device-ID (``):** Identifies a specific device. This ID is a unique UUID and can be found in the device metadata or URL. * **Field-Name (``):** The field name of the measured value as it appears in the database. Use uppercase for consistency. ### Examples #### **Subscription** Subscribe to all measurements of a specific device: ```plaintext dtck/my-product/6b98a3bb-9ae1-418f-9375-f23091a849cd/+ ``` Subscribe to all temperature measurements of all devices under a product: ```plaintext dtck/my-product/+/TEMPERATURE ``` #### **Publish** Publish a temperature measurement to a specific device: ```plaintext publish("dtck-pub/my-product/6b98a3bb-9ae1-418f-9375-f23091a849cd/TEMPERATURE", 22.003) ``` ### Use Case The internal broker is ideal for users needing fast, secure, and real-time data ingestion directly into the Datacake database, with the limitation of a fixed topic structure and single measurement messages. ### More Information For detailed setup instructions, refer to the [Datacake Internal MQTT Broker Documentation](https://docs.datacake.de/api/internal-mqtt/get-started). ## External MQTT Brokers ### Overview The external MQTT brokers provide more flexibility for users needing custom topics and the ability to send multiple measurements in a single message. ### Features * **Custom Topics:** Users can define their own topics. * **Multiple Measurements:** Supports sending multiple measurements in a single message, including JSON format. * **Payload Decoders:** Utilizes payload decoders for processing subscriptions from external brokers. * **Third-Party Integration:** Integrates with various third-party MQTT brokers. ### Use Case The external broker is suitable for users requiring flexible topic structures, complex payloads, or integration with third-party systems. ### More Information For detailed setup instructions, refer to the [Datacake External MQTT Broker Documentation](https://docs.datacake.de/integrations/mqtt). ## Summary | Feature | Internal MQTT Broker | External MQTT Brokers | | ---------------------------- | --------------------------------------------------- | ------------------------------------------------------------------- | | Real-time Communication | Yes | Depends on third-party broker | | Direct Database Integration | Yes | No | | Fixed Topic Structure | Yes | No | | Custom Topics | No | Yes | | Multiple Measurements | No | Yes | | Payload Decoders | No | Yes | | User Authentication Required | Yes | Depends on third-party broker | | Performance | Fastest | May vary | | Use Case | Direct database ingestion, real-time status updates | Flexible topic structure, complex payloads, third-party integration | This guide should assist users in understanding the differences between the internal and external MQTT brokers provided by Datacake, helping to choose the right broker based on specific needs. --- # 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. 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