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toml-lang/toml

📈 Trending★ 20,488Audience · developerComplexity · 1/5ActiveLicenseSetup · easy

TLDR

TOML is a human-friendly configuration file format that's easy to read and write, sitting between JSON's simplicity and YAML's readability while avoiding their pitfalls.

Mindmap

mindmap
  root((TOML))
    What it does
      Configuration format
      Human readable
      Machine parseable
    Design goals
      Simple data types
      Unambiguous mapping
      Comment support
    Compared to others
      Better than JSON
      Better than YAML
      Better than INI
    Use cases
      Config files
      App settings
      Package metadata
    Tech stack
      Language agnostic
      Multiple parsers
      Test suite

Things people build with this

USE CASE 1

Write configuration files for applications that are easier to read and edit than JSON or YAML.

USE CASE 2

Define package metadata and dependencies in a standardized, human-friendly format.

USE CASE 3

Create settings files for tools and services that need clear structure without parsing ambiguity.

USE CASE 4

Build parsers and validators for TOML in any programming language using the official test suite.

Tech stack

TOMLJSONYAMLINI

Getting it running

Difficulty · easy Time to first run · 5min
Use freely for any purpose including commercial, as long as you keep the copyright notice.

In plain English

TOML (Tom's Obvious, Minimal Language) is a configuration file format designed to be easy for humans to read and write. This repository contains the in-development version of the TOML specification, with released versions available at toml.io. TOML is designed to map unambiguously to a hash table, a simple key-value data structure, and is intended to be straightforward to parse in any programming language. Its goals place it between JSON and YAML: like JSON, it uses simple and unambiguous data types, making it easy to process with machines; like YAML, it supports comments and prioritizes human readability. Unlike JSON, TOML allows comments in configuration files. Unlike YAML, it keeps the format simple and avoids the many edge cases and surprises that YAML parsers face. TOML is explicitly intended for configuration files rather than general data serialization. It always has a hash table at the top level, supports nested data within keys, but does not permit top-level arrays or floats and has no standard for marking the start or end of a file. Compared to INI files, TOML supports deeper nesting with a standardized format. The official TOML wiki catalogs projects using TOML, implementations across languages, validators, editor support, and a language-agnostic test suite for TOML decoders and encoders.

Copy-paste prompts

Prompt 1
Show me how to write a TOML configuration file for a web application with database settings, API keys, and feature flags.
Prompt 2
What are the key differences between TOML and YAML for configuration files, and when should I use each one?
Prompt 3
Help me parse a TOML file in [my language] and convert it to a dictionary or object.
Prompt 4
Create a TOML schema validator that checks if a config file matches my expected structure.
Prompt 5
Explain the TOML syntax for nested tables, arrays of tables, and inline tables with examples.
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Generated 2026-05-18 · Model: sonnet-4-6 · Verify against the repo before relying on details.