Stalwart Mail Server uses the TOML (Tom's Obvious, Minimal Language) format for its configuration file, which is by default located under /etc/config.toml. This format is ideal for configuration files as it is human-readable, and easy to write and parse, which means that even non-programmers can easily understand and modify the configuration. Its syntax is designed to be simple and consistent, with a focus on readability, and it has clear rules about how to specify and overwrite properties. Moreover, TOML supports complex data types such as arrays, tables, and inline tables, and it has built-in support for dates and times, which can be useful in certain configurations.
Context or environment variables may be used in certain settings of the configuration file that accept rules or dynamic values. The available context variables for evaluation vary depending on the setting and can include: