DevKit - All-in-One Developer Tools

45+ developer tools in one: JSON/JWT/Base64, regex, QR codes, diff & compare, color picker, page ruler, SEO & performance audit.

Stop juggling a dozen single-purpose extensions. DevKit packs 45+ developer tools into one fast, private popup. ★ CODE & DATA JSON formatter with tree view, Base64, URL and HTML-entity encoders, JWT decoder, number-base converter, CSV/JSON and query-string converters, SQL formatter, and Markdown preview. ★ GENERATORS UUIDs, SHA hashes, secure passwords, QR codes, mock data, and lorem ipsum. ★ DESIGN Color converter, screen eyedropper, WCAG contrast checker, px/rem calculator, and box-shadow & gradient builders — all with live preview. ★ TEXT & COMPARE Regex tester, case converter, word counter, line tools, slugify and string escaper — plus a full compare suite: text diff, JSON diff, list compare, text similarity, date diff, number diff and image diff. ★ TIME & REFERENCE Timestamp converter, cron explainer, and quick references for HTTP status codes, MIME types and User-Agent strings. ★ ON-PAGE TOOLS & ANALYSIS Element ruler, font inspector, outline overlay, palette extractor and full-tab screenshots. Plus on-demand page analysis: SEO checks, performance metrics, a storage viewer and framework detection. ★ PRIVATE BY DESIGN Everything runs locally. No servers, no accounts, no analytics, no data collection — just three narrow permissions (activeTab, scripting, storage). DevKit only touches a page when you click a button. Dark & light themes. Searchable tool list. Keyboard shortcut: Alt+Shift+D.