TOML - A Configuration File Format For Humans#

TOML is a configuration file format designed with human-friendliness in mind. At its core, TOML is meant to be¹:

• is easy to read due to obvious semantics
• maps unambiguously to a hash table
• is easy to parse into data structures in a wide variety of languages

The Power of TOML Lies in its Versatility#

What makes TOML so powerful is its ability to cater to different forms of data. It supports a variety of native types such as ¹:

• Key/Value Pairs.
• Arrays.
• Tables.
• Inline tables.
• Arrays of tables.
• Integers & Floats.
• Booleans.
• Dates & Times, with optional offsets.

Wide Support Across Langauges#

TOML is supported in most of the most popular programming languages including C, C#, C++, Clojure, Dart, Elixir, Erlang, Go, Haskell, Java, JavaScript, Lua, Objective-C, Perl, PHP, Python, Ruby, Rust, Scala, Swift, and plenty more.

A quick look at a few libraries for python, C++ and Julia:

• tomllib is a read-only parser and serializer for Python. From Python 3.11 onwards tomlib is included in the Python Standard Library.
• tomlplusplus and toml11 are two great libraries for parsing and serializing TOML in C++17 and C++11 respectively.
• TOML.jl is a Julia standard library for parsing and writing TOML v1.0 files.

TOML vs Other Formats²#

Compared to other formats like XML, .cfg, .ini, YAML, JSON, and even Python files, TOML strikes an excellent balance between verbosity, complexity, and functionality.

• XML tends to be overly verbose.
• .cfg and .ini formats often lack flexibility.
• YAML and TOML are both user-friendly and powerful.

While JSON is widely used, its lack of support for comments can be a drawback, making TOML a preferred alternative for many.

In conclusion, TOML is a robust and versatile configuration file format that meets a wide range of programming needs effectively.