Development
Test expressions and inspect the formats developers use daily.
Regex Tester
Test JavaScript regular expressions and inspect matches, groups, and indices.
Regex Replacer
Replace text with JavaScript regex patterns and capture references.
Chmod Calculator
Convert three-digit Unix permissions and symbolic owner/group/other clauses.
SemVer Parser
Split semantic versions into numeric, prerelease, and build components.
SemVer Compare
Compare two semantic versions using prerelease precedence rules.
CSS Specificity Calculator
Calculate ID, class, and type specificity for selectors and selector lists.
JSONPath Evaluator
Query JSON with an explicit safe subset of JSONPath expressions.
.gitignore Generator
Generate practical ignore files from built-in language and OS templates.
package.json Validator
Check common npm manifest structure, versions, fields, and dependency mistakes.
Docker Run Parser
Parse docker run flags, image names, and container command arguments.
Dockerfile Basic Linter
Run transparent structural and best-practice checks on Dockerfile text.
JSON Diff
Recursively compare two JSON documents and report structured changes.
Open Graph Meta Generator
Generate complete Open Graph and Twitter card meta tags from JSON or four lines.
Keyboard Event & Keycode Inspector
Inspect keyboard key, code, legacy keyCode, location, and modifier state accessibly.
HTML WYSIWYG Editor
Edit rich text visually and export sanitized HTML with headings, lists, and links.
Safe JavaScript Benchmark Builder
Benchmark a restricted set of JavaScript-like expressions without eval.
Git Cheatsheet
Search a practical reference of common Git commands and workflows.
Regex Cheatsheet
Search regular-expression tokens, assertions, groups, and quantifiers.