Free, client-side web tools. No install, no server, no tracking.
Each one is a single HTML file — just open and use.
Markdown viewer & editor with live preview, syntax highlighting, math (KaTeX), Mermaid diagrams, PDF export, and shareable links.
Drawing & photo editor with brushes, shapes, text, crop, resize, filters, layers, undo/redo, zoom, and export to PNG/JPG/WebP.
JSON formatter, validator, tree viewer, diff, and transform toolkit — sort keys, flatten, decode JWT/Base64, generate TypeScript, and more.