Small, fast tools that do one thing well.
Free, single-purpose utilities for web and mobile developers. No sign-up, no uploads — everything runs in your browser.
Why The Dev Toolset?
- One task per toolEach page does a single thing well, so you're in and out in seconds — no sprawling all-in-one dashboards.
- Runs in your browserNothing you paste is uploaded. There's no backend, so the tools stay private and keep working offline once loaded.
- Free, no sign-upNo accounts, no paywalls, no trial limits — open the page and use it, with a short guide next to every tool.
SEO tools
Tools to check, preview, and improve how your pages appear in search engines.
Developer tools
General-purpose utilities for everyday front-end and back-end work — formatting, conversion, and validation.
- DevColor Contrast Checker — WCAG AA & AAA Accessibility ToolFree online color contrast checker for WCAG AA & AAA. Test any CSS color (HEX, RGB, HSL, OKLCH) for accessibility, with APCA preview, color-blindness simulation, and a one-click fix to pass.
- DevCSS px to rem Converter and rem to px ConverterFree px to rem converter (and rem to px): convert one value or a whole CSS block, with a configurable root font size. Instant, bidirectional, 100% in your browser.
- DevFavicon Checker — Test & Validate Your Favicon Online (Free)Free favicon checker: paste your <head> HTML or enter a URL to audit favicon.ico, SVG favicon, apple-touch-icon, the full web app manifest, and theme-color. Get a graded, platform-by-platform report, live previews of how your icons actually render, and cleanup advice for legacy tags. 100% in your browser.
- DevFavicon Generator — Free Online favicon.ico, SVG & Apple Touch IconFree online favicon generator: turn any image — PNG, JPG, SVG, or even text or an emoji — into favicon.ico, an SVG favicon with dark mode, apple-touch-icon, and PWA manifest icons. No signup, no AI, 100% in your browser.
- DevUnix Timestamp Converter — Epoch to Date, UTC/EST/GMT, Discord & HexFree Unix timestamp converter: epoch to date and back, in UTC, EST, PST, GMT, or any time zone. Auto-detects seconds vs milliseconds, plus hex input and Discord timestamp codes. No signup, 100% in your browser.
Mobile tools
Tools for building and shipping mobile and desktop apps, from icons to platform assets.
Frequently asked questions
Is The Dev Toolset free?
Yes. Every tool is completely free — no account, no sign-up, no usage limits, and no paywalled features.
Do the tools upload my data anywhere?
No. Every tool runs entirely in your browser with client-side JavaScript. The text, files, and images you paste never leave your device — there is no backend to send them to.
Can I use the tools offline?
Once a tool's page has finished loading, it keeps working without a connection, because all the processing happens locally in your browser.
Can I trust the output?
Each tool uses native browser APIs and documented formulas rather than guesswork, and every page includes a short guide explaining exactly how the result is produced.
Can I use these for commercial work?
Yes. Output such as generated favicons, app icons, and converted CSS values is yours to use in personal or commercial projects, free of charge.
How often are new tools added?
New tools are added regularly. If there is one you'd like to see, you can request it from the contact page.