SimpleTools

Offline-first developer toolbox. All processing stays on your device. / 纯前端离线开发者工具箱，数据不离开本机。

SimpleTools is an offline-first developer toolbox that runs entirely in your browser. Format JSON, test regex, convert files, edit PDFs, work with Excel/Word, and use AI/Agent helpers — with no account and no server. Your data never leaves your device. Why SimpleTools • Privacy by design: all processing is local; nothing is uploaded • Works offline after install: ideal for sensitive code, docs, and files • 100+ tools in one place: developer utilities, encode/decode, converters, text, images, PDF, Office, compression, and AI/Agent helpers • Bilingual UI: Chinese and English • Fast access from the toolbar: open the full toolbox in a new tab Popular capabilities • Developer: JSON/JWT/regex, formatters, cron, checksums, CIDR, and more • PDF: merge, split, rotate, compress, watermark, redact, convert to/from images and Office formats • Office: view and convert Excel / Word, CSV ↔ Excel, create documents • AI / Agent: token counter, API cost estimator, prompt linter, secret redactor, injection scanner, MCP config builder, agent instruction generator • Media & convert: image tools, color/units, Markdown/HTML, Base64, QR, and more SimpleTools is Manifest V3, requests no host permissions, and keeps every operation on your machine. Install once, then use it anytime — even without a network.