Validators Tools

Validate syntax before it reaches production. Our YAML and JavaScript validators report precise line and column errors and never execute or upload your source.

YAML Validator

Validate YAML syntax with precise line and column errors.

JavaScript Validator

Check JavaScript syntax without executing your code.

Regex Tester

Test regex patterns against sample text with match offsets and capture groups.

JSON Path Evaluator

Evaluate JSONPath expressions against JSON documents.

XPath Evaluator

Evaluate XPath against XML or HTML in your browser.

HTML Validator

Structural HTML lint - unclosed tags, duplicate ids, and common issues.

Redirection Checker

Check URL reachability and redirect hints from your browser.

Link Checker

Bulk-check links extracted from HTML or a URL list.

JSONPath Finder

Find JSONPath expressions for a key or value in JSON.

Frequently Asked Questions

How is a validator different from a formatter?

Validators focus on correctness and error location. Formatters rewrite whitespace for readability.

Do you run JavaScript I paste?

No. The JavaScript Validator parses only - never eval.