JPG and PNG Converter
Load a local image, remove a simple background with traditional color-distance matting, refine alpha with mouse or touch, then export PNG or JPEG.
UsefulTool
Portable browser tools for private, local work. Open a page, use the tool, inspect the source, or keep the repository for offline use.
Open Image Tool
Open Calculator
Open Units
Open Metadata
Open Base64
Open Diff
Open Text Editor
Open Text Upload
Open ROT
Open LAN Chat
Open Image Editor
Open PDF Merge
Open Images to PDF
Open PDF to Text
Open Video Editor
Open Image Compressor
Open PDF Compressor
Open Lightweight Video Compressor
Open Sticker Builder
Tools
Tools run locally in the browser. Advanced pages use audited libraries stored in this repository, never runtime CDNs.
Scientific Calculator
Calculate common functions, trigonometry, powers, constants, and definite integrals locally with a parser that avoids dynamic code execution.
Unit Converter
Convert 18 measurement categories, including scientific, imperial, mechanical, time, angle, frequency, torque, density, acceleration, and digital-rate units.
Image and Video Metadata
Decode EXIF/GPS, XMP, ICC, IPTC, text chunks, and major image/video containers locally, with explicit privacy and secret-like field warnings.
Base64 Converter
Encode text or files, decode standard, URL-safe, and Data URI Base64, inspect bytes, and save binary output.
Side-by-Side File Diff
Compare two text files line by line with aligned additions and removals powered by the vendored jsdiff implementation.
Text Editor
Edit autosaved local drafts with line numbers, regex find and replace, Markdown preview, formatting, and word-count analysis.
Text Upload and Download
Upload a text file, edit lightly, download it again, or hand the content to the editor and side-by-side diff pages.
ROT Cipher
Apply Caesar rotations, ROT13, ROT47, inspect every shift, or generate a random password before reversible transformation.
LAN Chat
Exchange manual WebRTC signaling text, then send messages and images directly between LAN peers without a room server.
Layered Image Editor
Load multiple images as interactive layers, move, resize, rotate, reorder, and export with configurable JPEG or WebP quality.
PDF Merge
Preview local PDF pages, select per-file ranges or individual pages, reorder files, and inspect the merged output.
Images to PDF
Order image files, configure page sizing, margins, captions, and compression, then create a multi-page PDF.
PDF to Text — No OCR
Extract machine-readable text from selected PDF pages locally, with content-order or approximate visual-line output and no OCR.
Local Video Editor
Import many local videos at once, drag storyboard clips into any order, split and trim them, add timed transparent PNG layers, mix each clip’s left and right audio independently, preview the full movie, and export locally.
Image Compressor
Fit a still image below a chosen file size by comparing quality and dimensions, with original and result previews.
PDF Compressor
Optimize embedded images toward a measured size limit while retaining text and links, with an optional page-image fallback.
Lightweight Video Compressor
Change resolution, frame rate and encoding locally while retaining the full video and its audio tracks.
Sticker Builder
Build circular text stickers with spacing, ring and text layers, glow, rotation and transparent PNG export.
Runtime pages declare `connect-src 'none'` and also disable common network functions in JavaScript. Images and expressions stay inside your browser process.