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TOML Validator

Validate TOML tables, keys and values, with the line of the first problem reported.

Your TOML

Status: —
Tables: — · Key values: —

Report

—
Multi-line strings and multi-line arrays are followed to their closing delimiter.

How to use the TOML Validator

  1. Paste the TOML document you want to check.
  2. Click Validate to parse tables, keys and values in order.
  3. Read the report: it names the first line that fails and why.

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Frequently Asked Questions

Common questions about the free online toml validator.

It parses each line as a table header or a key value pair and confirms that keys, strings, numbers, dates, arrays and inline tables are well formed.
A value that opens a bracket or a triple quoted string is followed across lines until the matching closing delimiter is found.
Offset date times, local date times, local dates and local times, for example 1979-05-27T07:32:00Z or 1979-05-27.
The checker focuses on syntax and types. Duplicate keys are a semantic error that a TOML parser reports when it loads the file.
Later lines often depend on earlier ones, so reporting the first failure avoids a cascade of misleading messages.
Yes. A hash starts a comment unless it appears inside a quoted string, and comments are ignored during validation.
No. Parsing happens entirely in your browser, so the file stays on your device.
Yes, the TOML validator is completely free and unlimited, with no account required.

Last updated: October 10, 2026