TOML Validator
Validate your TOML configuration files
Input TOML
Validation Result
What is TOML Validator?
A simple tool to check if your TOML (Tom's Obvious, Minimal Language) configuration file is valid or broken. Paste your TOML, upload a file, or try the sample data – you'll see right away if there are any syntax errors.
Uses TOML parser following the TOML v1.0.0 specification, so it follows the same rules as TOML parsers. According to the TOML specification, proper validation prevents configuration errors and ensures your config files work correctly. Everything runs locally in your browser – nothing gets sent to any server.
Features
Real-time Validation
Checks your TOML as you type. Green badge means it's valid, red means there's an error.
Error Details
Shows the line number and what went wrong. Makes debugging way easier.
File Upload
Upload TOML files directly instead of copy-pasting everything.
Sample Data
Try the sample button to see valid TOML examples.
Syntax Highlighting
Color-coded TOML makes it easier to spot issues visually.
Local Processing
Everything runs in your browser. Your data stays on your machine.
How to Use
Add Your TOML
Paste TOML into the left editor, upload a file, or click the sample button to try it out.
Check Results
The right panel shows validation results automatically. Green = valid, red = has errors. Error messages include line numbers.
Fix Issues
Use the error details to fix problems. Usually it's syntax errors, invalid table definitions, or type mismatches. The validator updates as you fix things.
Use Cases
Config Files
Validate TOML config files before deployment. One typo can break everything. Perfect for Cargo.toml, pyproject.toml, or any TOML-based configuration.
Learning
If you're new to TOML, use this to check your work and see what errors look like.
Debugging
Getting parse errors? Validate the TOML first to find the exact problem.
CI/CD
Validate TOML files in CI/CD pipelines before deployment. Catch errors early before they cause issues.
FAQ
Is my data stored?
No. Everything runs in your browser using TOML parser. Nothing gets sent anywhere.
What makes TOML invalid?
Syntax errors, invalid table definitions, type mismatches, or invalid characters. The validator will tell you exactly what's wrong.
Does it validate TOML schema?
No, this only checks syntax. For schema validation, you'll need additional tools or custom validation logic.
Can I validate large files?
Yes, but performance depends on your browser. Small files are instant. Very large files (10MB+) might take a moment.
Why is my TOML invalid?
Check the error message – it shows the line and what's wrong. Usually it's syntax errors, invalid table definitions, or type mismatches.
Related Tools
Other TOML tools you might find useful:
Need to learn more about TOML? Check out TOML.io or the TOML v1.0.0 specification.