CruxDev — 301 Free Developer Tools That Run In Your Browser

Formatters, converters, encoders, generators and calculators that execute entirely on your own machine. Nothing you paste is uploaded, queued, logged or stored on a server.

Why the work happens in your browser

Most online utilities POST your input to a backend, which means an API key, a customer record or a production log line leaves your control the moment you click convert. CruxDev tools are plain JavaScript running in the page you already loaded, so the data never crosses the network. You can verify it: open your browser devtools, watch the Network tab, and use any tool on this site.

Browse by category

  • Daily Life Tools — 13 tools

    Everyday calculators and converters for the whole world - health, money, kitchen, time, and random picks. All offline.

  • AI & LLM Tools — 10 tools

    AI-era utilities: token and cost estimators, prompt tooling, secret scanners, and schema generators - all fully in-browser.

  • Text Tools — 39 tools

    Analyze, format, clean, and convert text formats instantly.

  • Developer Tools — 92 tools

    Format, validate, parse, and hash code structures in-browser.

  • CSS Generators — 36 tools

    Visually build, customize, and copy responsive CSS stylings.

  • UI Components — 9 tools

    Copy-ready UI components for every platform: Flutter, Jetpack Compose, SwiftUI, React Native, React, Vue, Tailwind & HTML/CSS.

  • Color Tools — 7 tools

    Convert hex/rgb values, generate harmonic palettes, and simulate.

  • Security Tools — 19 tools

    Generate cryptographically secure passwords and strength metrics.

  • Unit Converters — 5 tools

    Convert metric, imperial, temperature, and storage parameters.

  • Finance & Math — 17 tools

    Calculate percentage matrices, loan EMIs, and bio indices.

  • Image Tools — 12 tools

    Compress, resize, crop, watermark, and inspect images entirely in your browser.

  • File Converters — 9 tools

    Convert images and extract text from PDFs securely offline.

  • Productivity — 19 tools

    Protect focus, build habits, and keep useful work local to your browser.

  • Network & Web Tools — 14 tools

    IP converters, subnet calculators, MAC generators, port tools, URL parsers, and web header builders — all offline.

No account, no upload limit, no paywall

There is nothing to sign up for. Because each tool is client-side, the size of the file you process is limited by your own memory rather than by an upload quota, and the tools keep working after you go offline.