Syntax & Logic Checkers

Validate Code & Data Instantly

Don't let a missing comma break your build. Validate JSON, check XML structure, and lint Code files directly in your browser.

Secure Validation (No Uploads)
Exact Error Line Detection
Standard Compliance

Validation Tools

18 Linters Available

Why Validate Online?

Ensure your data integrity and code quality before deployment.

Data Integrity

Working with JSON APIs or XML feeds? One syntax error can crash your application. Our validators parse your data structure to find missing brackets, unclosed tags, or invalid types instantly.

Configuration Safety

DevOps engineers use our tools to check YAML, TOML, or ENV files. Because we run locally (client-side), you can safely paste configs containing sensitive API keys without fear of leaks.

Web Standards

Ensure your markup meets W3C standards. Validating HTML and CSS helps prevent browser rendering issues and improves your website's SEO performance by ensuring clean code.

Validation FAQ

What is the difference between Validating and Formatting?

Formatting (Beautifying) makes code readable. Validating (Linting) checks if the code is actually correct and follows the rules of the language.

Is it safe to validate files with passwords/keys?

On Selqio, yes. Because we use Client-Side processing, your data never leaves your computer. We recommend this over server-based validators for sensitive data.

Do you fix the errors automatically?

Our tools will highlight the exact line and reason for the error. Some tools (like JSON Validator) have a "Fix" button for common syntax mistakes.

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