Free online TOML to INI converter

Source format: TOML

TOML stands for Tom’s Obvious, Minimal Language. It is a human-readable configuration format designed to be easy to write and easy to parse. TOML is widely used by developers for application settings, project metadata, and build configuration files, especially in modern software ecosystems such as Rust, Python tooling, and other developer-focused projects.

TOML supports nested tables, arrays, dates, booleans, numbers, and strings. It is valued for its clarity and for reducing ambiguity compared with older configuration formats.

Target format: INI

INI is a simple configuration file format that uses sections, key-value pairs, and comments. It has been used for decades in Windows applications, desktop software, and many cross-platform tools. INI files are easy to read and edit manually, which makes them useful for basic application settings and legacy compatibility.

The main advantage of INI is its simplicity and broad support. However, it is less expressive than TOML: it has limited support for data types, no standard nested structure, and inconsistent handling across parsers.

How to perform the conversion

There is no perfect one-to-one conversion from TOML to INI because TOML can represent richer data structures than INI. The best approach is to flatten the TOML structure into INI sections and simple key-value pairs.

1. Inspect the TOML file and identify the top-level tables, nested tables, arrays, and non-string values.
2. Decide on a flattening strategy. Commonly, each TOML table becomes an INI section, and nested tables are represented with dotted or combined section names.
3. Convert simple values such as strings, integers, booleans, and floats into INI key-value pairs.
4. Handle arrays carefully. INI does not have a universal array syntax, so arrays may need to be joined into comma-separated strings or repeated keys, depending on the target application.
5. Review unsupported TOML features such as inline tables, multiline strings, dates, and deeply nested structures, then simplify them for INI compatibility.
6. Validate the result by opening the INI file in the target application or testing it with an INI parser.

If you want a quick browser-based conversion, you can convert the file on 101convert.com for free, without installing any software.

For manual conversion, a text editor such as Visual Studio Code, Notepad++, or Sublime Text is often enough for small files. For larger or repeatable conversions, a scripting approach is better. For example, you can use Python with a TOML parser and write custom logic to emit INI syntax.

Example mapping:

[database]
host = "localhost"
port = 5432

could become:

[database]
host=localhost
port=5432

Quality, compatibility, and limitations

The biggest limitation in this conversion is that INI cannot fully preserve TOML structure or data types. TOML arrays, nested tables, and typed values often need to be simplified, which can cause information loss. If the INI file must be used by a specific application, follow that application's expected INI conventions, because section naming, repeated keys, and value formatting can vary.

For best results, keep the TOML file as the authoritative source when possible and generate INI only for compatibility with software that requires it. If the configuration is complex, consider whether the target application can accept TOML directly instead of converting.