HubKit.dev — Free Online Developer Tools

40+ free developer tools that run locally in your browser.

Tools

JSON Formatter — Pretty-print, minify and validate JSON.
JSON ↔ YAML — Convert between JSON and YAML.
Beautifier — Format HTML, CSS or JS.
Minifier — Strip whitespace from HTML, CSS or JS.
SQL Formatter — Beautify and format SQL queries.
XML Formatter — Pretty-print and validate XML.
Markdown Preview — Write Markdown and see a live HTML preview.
Base64 — Encode and decode Base64 strings.
URL Encode — Encode and decode URL components.
JWT Decoder — Inspect JSON Web Tokens.
Base64 Image — Encode images to Base64 or decode to preview.
QR Code — Generate QR codes from text or URLs.
Hash — MD5, SHA-1, SHA-256, SHA-512.
File Checksum — Calculate checksums for files.
UUID — Generate v4 UUIDs in bulk.
Lorem Ipsum — Generate placeholder text.
Password Generator — Generate strong random passwords.
Regex Tester — Test patterns with live highlighting.
Diff Checker — Compare two blocks of text.
Timestamp — Convert Unix time to dates.
Date Formatter — Convert dates between formats.
Timezone Converter — Convert times between timezones.
Number Base — Convert between decimal, hex, octal, binary.
JSON → Table — Convert JSON arrays to tables and CSV.
Cron — Describe cron expressions in English.
Color — Convert HEX, RGB and HSL.
HTML Entities — Encode and decode HTML entities.
Case Converter — Convert text between cases.
Word Counter — Count words, characters, lines, sentences.
Slugify — Generate URL-friendly slugs from text.
JSON Path — Query JSON with path expressions.
CSV Viewer — Parse and view CSV data as a table.
String Escape — Escape and unescape strings for code.
Aspect Ratio — Calculate aspect ratios and resize dimensions.
Robots.txt — Generate robots.txt with bot and path rules.
Sitemap.xml — Build XML sitemaps for search engines.
LLMs.txt — Generate llms.txt for AI-friendly sites.
PHP Serialize — Serialize and unserialize PHP values.
PHP Array → Object — Convert a PHP array literal to an object.
PHP Array → JSON — Convert PHP array literal to JSON.