TOML Validator

Valid TOML: 1 table(s), 2 key(s).

How it works

• Scanned line by line, ignoring `#` comments and blank lines.
• Recognised table headers, key/value pairs and multi-line strings.
• Tracked duplicate keys and unterminated strings, arrays or inline tables.

• This is a pragmatic structural validator, not a full TOML parser: it reports the common syntax and structure errors and their location.
• Values are not type-checked against their TOML types beyond basic quoting; it is a syntax check, not a schema check.

Methodology

1. Strip comments with quote awareness.
2. Track multi-line strings, tables and inline/array nesting.
3. Detect duplicate keys and report unterminated constructs with their starting line.

Usage

1. Paste TOML content.
2. Read the errors with their line and column.
3. Fix and re-validate until the file is valid.

Examples

These are examples, not current values: they use fixed inputs, while the interactive tool computes live results in your browser.

Valid document

{
  "content": "title = \"Example\"\n[server]\nport = 8080"
}

Duplicate key

{
  "content": "name = \"a\"\nname = \"b\""
}

Unterminated string

{
  "content": "name = \"unterminated"
}

Limitations

What TOML is used for

TOML is a minimal configuration format used by Rust's Cargo, Python's pyproject and many build tools. It is line-oriented, so a single bad key or an unterminated string invalidates the whole file.

This validator reports the location of those faults so you can fix them quickly. It is a syntax check; run the consuming tool to enforce the schema your project expects.