TOML Config Example: Valid Server Settings with Tables and Arrays
Check TOML-like lines for section headers, key = value pairs, duplicates, and simple quotes and brackets.
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About this tool
This page opens the TOML validator preloaded with a small, realistic configuration file: top-level metadata keys including an inline tags array, a [server] table with a nested [server.limits] sub-table, and a repeated [[plugins]] array-of-tables block listing two plugin entries. The pass result below is computed the instant the page loads, using the same parsing rules as any file you paste in.
TOML's table and array syntax is where hand-written config files most often go wrong, so this example is built to exercise the parts that matter: a dotted sub-table name, an inline array with a trailing bracket on the same line, and the double-bracket [[...]] syntax that TOML uses specifically to allow a table header to repeat — the one case where the same header appearing twice is not an error. It mirrors the shape of a real Cargo.toml, pyproject.toml or application settings file.
Paste your own TOML into the box to check it the same way. If a single-bracket table header like [server] is accidentally repeated, or a key is duplicated inside the same table, the validator reports the exact line — the same class of mistake demonstrated on the duplicate-table-error preset page.
Example. [server]\nport = 8080 passes. A second [server] fails with Duplicate TOML section header. A second [[products]] is allowed. port = 1 and another port = 2 in the same section fail with Duplicate key "port".
Limit. The check is line-oriented. Dotted keys are not nested, multiline values must fit the one-line quote test, and a semicolon is treated as a comment even though standard TOML comments start with #.