The core automation framework (actions, triggers, and conditions) has been optimized to use const references instead of pass-by-value for parameter passing. This reduces memory allocations by 83% in the automation execution path.
This is a breaking change for external components with custom actions or conditions in ESPHome 2025.11.0 and later.
At the beginning of this year, we made the transition from IDF 4.4 to IDF 5.1; this was a major upgrade and many changes were necessary within ESPHome to achieve this.
In order to align all of the top level platform components (listed below), we are deprecating the *_SCHEMA constants that are present. Some examples are SENSOR_SCHEMA, SWITCH_SCHEMA and so on.
ESPHome’s “custom component” mechanism was a holdover from Home Assistant’s feature by the same name. It existed before external components and offered a way to “hack in” support for devices which were not officially supported by ESPHome.
Welcome to the first post of this new ESPHome Developer Documentation. This is a place where you can find all the information you need to start developing for ESPHome. This website will cover everything you need to create components and how to structure your code so that it will be easy to maintain and understand.
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