Code Formatters — 9 Free Online Tools
Format, validate and beautify JSON, HTML, SQL, CSS, YAML and XML with exact error positions. Everything runs in your browser, so your code never leaves your device.
A formatter only earns its keep when it tells you why your input is broken, so each of these reports the exact line and character of a syntax error instead of quietly reindenting bad data. Start with the JSON Formatter for API responses and config files, the SQL Formatter for a dump that arrived on one line, and the JSON Diff when you need to know what actually changed between two payloads rather than just how they are spaced.
CSS Formatter and Validator - Beautify or Minify CSS
Free online CSS formatter and validator. Beautify messy CSS, minify for production, fix syntax errors. Instant results, no signup required.
Free YAML Validator - Validate & Format YAML Online
Free YAML validator and formatter. Validate YAML syntax, fix errors with line numbers, and format YAML for better readability. No signup required.
HTML Formatter - Format & Beautify HTML
Free HTML formatter. Beautify and minify HTML with correct indentation, and catch unclosed tags and invalid nesting before production. No upload.
JS Formatter and Beautifier - JavaScript Code
Free online JavaScript formatter and beautifier. Beautify messy JS, minify for production, validate syntax. No signup, 100% private browser processing.
JSON Diff - Compare Two JSON Documents and Find
Free JSON diff tool. Compare two JSON documents and see differences instantly. Highlights added, removed, and modified values. Side-by-side view.
JSON Formatter - Format & Validate JSON
Free JSON formatter. Format, minify and beautify JSON, convert to and from YAML, and get the exact line of any syntax error. 100% browser, no upload.
JSON Schema Validator - Validate JSON Against Schema Online
Free online JSON Schema validator. Validate JSON data against Draft-07, 2019-09, and 2020-12 schemas. Detailed error paths, all-errors mode. No signup.
SQL Formatter - Format & Beautify SQL
Free SQL formatter. Beautify queries with correct indentation for MySQL, PostgreSQL, SQLite and SQL Server, and catch unbalanced syntax. No signup.
XML Formatter - Format, Validate & Beautify XML Online
Free XML formatter and validator. Format, beautify, minify XML, convert to JSON, and validate well-formedness. Browser-based, no signup, 100% private.
Frequently Asked Questions
4 Q&AWhich languages and formats are supported?
The 9 formatters cover JSON, HTML, CSS, SQL, YAML, XML, and JSON Schema (Draft-07, 2019-09, 2020-12). All run in the browser; no code is uploaded.
What is the difference between beautify and minify?
Beautify adds consistent indentation and line breaks to make code human-readable. Minify removes whitespace, comments, and optional tokens to shrink the file size for production. Most formatters offer both modes.
How large a file can I format?
In practice files up to several megabytes format instantly because the work is done in the browser. Files larger than that may slow down the page or hit browser memory limits; for very large files use a CLI tool.
Is my code sent to a server?
No. The formatters are pure JavaScript that run locally in your browser. Your code, schemas, and data never leave your device.
How to Use These Code Formatter Tools
guideEvery code formatter tool below runs entirely in your browser — no signup, no upload, no watermark. To find a specific tool, type a name, keyword, or scenario into the search box and the list filters instantly. Popular code formatter tools are linked in the summary at the top; click any card or link to open the tool and follow the on-screen instructions. Hover any tool card to read its full description, then click its name or button to open it.