TOML Tables and JSON Objects

Tables are TOML's primary structuring mechanism, equivalent to JSON objects. Understanding tables is essential for working with any non-trivial TOML document.

TOML tables with a header:

[owner]
name = "Tom Preston-Werner"
organization = "GitHub"

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

Converts to JSON:

{
  "owner": {
    "name": "Tom Preston-Werner",
    "organization": "GitHub"
  },
  "database": {
    "server": "192.168.1.1",
    "ports": [8001, 8001, 8002],
    "enabled": true
  }
}

Table header syntax:

• [tablename] creates a new object in the output
• All key-value pairs below a header belong to that table
• A new header starts a new table

Dotted keys for inline nesting:

fruit.apple.color = "red"
fruit.apple.taste = "sweet"
fruit.orange.color = "orange"

Produces:

{
  "fruit": {
    "apple": { "color": "red", "taste": "sweet" },
    "orange": { "color": "orange" }
  }
}

Dotted table headers:

[servers.alpha]
ip = "10.0.0.1"
role = "frontend"

[servers.beta]
ip = "10.0.0.2"
role = "backend"

This creates a nested JSON structure with servers containing alpha and beta objects.

Key rules:

• Tables cannot be defined more than once (except with [[array]] syntax).
• Dotted keys and table headers can be combined, but a key cannot be redefined.
• The ordering of tables in TOML is preserved but not semantically meaningful in JSON (JSON objects are unordered by spec).