Contents

TOML

Configuration file format

TOML

Filename extension	.toml
Internet media type	Not registered[a]
Developed by	Tom Preston-Werner Community
Initial release	23 February 2013; 11 years ago (2013-02-23)
Latest release	1.0.0[2] 12 January 2021; 3 years ago (12 January 2021)
Type of format	Data interchange
Open format?	Yes
Website	toml.io

Tom's Obvious, Minimal Language (TOML, originally Tom's Own Markup Language^[3]) is a file format for configuration files.^[4] It is intended to be easy to read and write due to obvious semantics which aim to be "minimal", and it is designed to map unambiguously to a dictionary. Originally created by Tom Preston-Werner, its specification is open source. TOML is used in a number of software projects^[5][6][7] and is implemented in many programming languages.^[8]

TOML's syntax primarily consists of key = value pairs, [section names], and # (for comments). TOML's syntax somewhat resembles that of .INI files, but it includes a formal specification, whereas the INI file format suffers from many competing variants.

Its specification includes a list of supported data types: string, integer, float, boolean, datetime, array, and table.

# This is a TOML document.

title = "ImpalaPay Co."

[database]
server = "192.168.1.1"
ports = [ 8000, 8001, 8002 ]
connection_max = 5000
enabled = true

# Line breaks are okay when inside arrays
hosts = [
  "alpha",
  "omega"
]

[servers]

  # Indentation (tabs and/or spaces) is allowed, but not required
  [servers.alpha]
  ip = "10.0.0.1"
  dc = "eqdc10"

  [servers.beta]
  ip = "10.0.0.2"
  dc = "eqdc10"

TOML is used in a variety of settings (some related to its creator), such as:

• Static site generators like Jekyll and Hugo.
• Python programming language^[9]
• Rust package manifest^[5]
• Julia project setting and package manifest^[10]

TOML has been criticized on a number of points:^[11][12]

• TOML is verbose; it is not DRY and is syntactically noisy.
• TOML's hierarchies can be difficult to infer from syntax alone.
• Overcomplication: Like YAML, TOML has too many features.
• In TOML, the syntax determines the data types ("syntax typing").

• Configuration file § Comparison

• Official website