TOML Validator
Validate TOML config file syntax and find errors instantly in your browser
What is TOML Validator?
The TOML Validator checks your TOML configuration file syntax for errors and reports them with exact line numbers. TOML (Tom's Obvious Minimal Language) is used in Rust projects (Cargo.toml), Python projects (pyproject.toml), Hugo static sites, and many other tools. A missing quote, duplicate key, or invalid value can silently break your build. This tool catches those errors instantly in your browser.
Why Use DevBench TOML Validator?
DevBench tools are built with one principle: everything runs in your browser. Unlike most online tools that upload your data to remote servers, DevBench processes everything locally using client-side JavaScript. This means your files, code, and sensitive data never leave your device. There are no accounts to create, no usage limits, no watermarks, and no paywalls. Every tool on DevBench is completely free to use as many times as you need. Whether you are a professional developer, a student learning to code, or someone who occasionally needs a quick utility, DevBench gives you instant access to powerful tools without friction.
How to Use TOML Validator
Using the TOML Validator is straightforward and requires no installation or sign-up. Follow these steps to get started:
- Paste your TOML content into the input textarea
- Errors appear instantly with line numbers
- Click Load Sample to see correct TOML syntax
- The stats cards show total lines, error count, and validation status
- Fix errors and re-paste to confirm the TOML is clean
All processing happens directly in your browser, so your data stays private and results are instant.
Examples
Here are some common examples of how the TOML Validator is used in real-world scenarios:
- Validate a Cargo.toml file for a Rust project
- Check a pyproject.toml for Python packaging errors
- Validate a Hugo config.toml before building a static site
- Check a Gitea or Forgejo app.ini TOML config
- Validate a custom TOML config file for a CLI application
Use Cases
The TOML Validator is used by developers, designers, and professionals across many industries. Common use cases include:
- Rust developers validating Cargo.toml before building
- Python developers checking pyproject.toml syntax
- Hugo static site developers validating config.toml
- Anyone debugging TOML configuration file errors
- DevOps engineers checking TOML-based tool configs
- Students learning TOML syntax and structure
- Teams reviewing TOML config files before deployment
Whether you are a beginner learning the basics or an experienced developer working on complex projects, this tool is designed to fit seamlessly into your workflow.
Frequently Asked Questions
Here are answers to the most common questions about the TOML Validator:
What is TOML?
TOML (Tom's Obvious Minimal Language) is a configuration file format using key = value pairs, [table] sections, and [[array of tables]]. It is used in Rust (Cargo.toml), Python (pyproject.toml), and many other tools.
What are the most common TOML errors?
Common TOML errors include: duplicate keys in the same table, missing values after the equals sign, unmatched quotes in string values, and unclosed array brackets.
Is my TOML sent to a server?
No. All validation runs entirely in your browser using JavaScript. Your TOML content never leaves your device.
What is the difference between TOML and YAML?
TOML uses explicit key = value syntax and is less sensitive to indentation than YAML. TOML is generally easier to write correctly for configuration files.
Does this validate TOML data types?
This tool validates TOML structure and syntax including key format and duplicate detection. Full data type validation for dates, floats, and integers may not catch all edge cases.