📋 TOML Validator

What is TOML Validator?

The TOML Validator is an online tool designed for developers that validates TOML configuration file syntax in real-time. Paste your TOML content and the tool instantly checks key-value pair format, table header syntax, array structures, string quotes, and pinpoints error line numbers—especially useful for Rust and Python projects.

Core Features

• Key-Value Validation: Checks key name format, value types (string/number/boolean/date/array/inline table)
• Table Header Validation: Checks [table] and [[array]] syntax correctness
• Duplicate Key Detection: Detects duplicate key names within the same table
• String Checking: Validates quote pairing and multiline string format
• Error Line Detection: Each issue shows the specific line number

How to Use

Step 1: Paste TOML config content or click example buttons to load samples.

Step 2: Click "Validate" or use Ctrl+Enter shortcut.

Step 3: Review results showing error count, warning count, and passed checks.

Step 4: Fix issues based on error hints and re-validate until passing.

Use Cases

Case 1: Rust Project Configuration

Rust developers validate Cargo.toml dependency declarations and feature configurations.

Case 2: Python Project Configuration

Python developers validate pyproject.toml build system and tool configurations.

Case 3: CI/CD Configuration

Validate TOML config files before committing to avoid CI/CD pipeline failures.

Extended Knowledge

TOML (Tom's Obvious Minimal Language) was created by Tom Preston-Werner to be a more concise and explicit alternative to YAML. TOML v1.0 was released in 2021. Core features: key-value pairs (key = value), tables ([table]), array tables ([[array]]), inline tables ({key = val}), multiline strings (""" or '''), datetime types. Rust's Cargo.toml and Python's pyproject.toml are the most common TOML config files.