Formatters & Linters
19 toolsClean, well-formatted code is easier to read, review, and debug. These free online formatting and linting tools help you beautify, validate, and minify code instantly — no extensions, no IDE required. Great for quick code reviews, API debugging, or checking configs on the fly.
JSON Formatter
Format, validate & minify JSON
PopularSQL Formatter
Beautify & indent SQL queries
Markdown Previewer
Write Markdown, see live HTML preview
Code Minifier
Minify JS, CSS & HTML code
Diff Checker
Compare two texts, highlight changes
PopularRegex Tester
Test regular expressions with live matching
XML Formatter
Format, validate & minify XML
CSS Formatter / Minifier
Beautify or minify CSS stylesheets
HTML Formatter / Minifier
Beautify or minify HTML documents
JSONPath Tester
Test JSONPath expressions on JSON data
JSON Schema Validator
Validate JSON data against a JSON Schema
HTML WYSIWYG Editor
Rich text editor with live HTML output
JSON Diff
Deep compare two JSON objects & highlight differences
YAML Formatter
Format & prettify YAML documents
Nginx Config Formatter
Format & beautify Nginx configuration files
.env File Formatter
Sort, group & validate .env files
GraphQL Formatter
Format & prettify GraphQL queries
Dockerfile Linter
Lint Dockerfiles for best practices
Markdown Linter
Format & lint Markdown documents
What’s included
- JSON formatting, validation, and minification with error highlighting
- SQL query beautifier with dialect support
- XML, HTML, CSS, YAML, and GraphQL formatters
- Side-by-side text diff checker with line-level highlighting
- Live regex tester with match capture groups
- JSONPath expression tester and JSON Schema validator
- Dockerfile linter and Nginx config formatter
Common use cases
- Beautifying API response payloads for readability
- Validating configuration files before deployment
- Reviewing code changes with a quick text diff
- Testing and debugging complex regex patterns