Color Converter (HEX/RGB/HSL)
Convert between HEX, RGB, HSL, and CMYK colour formats instantly. Includes a visual colour picker and CSS-ready output.
Monthly fees for software you already paid to learn. Price hikes you can't avoid. Features removed behind higher tiers. One-time purchase, lifetime access. No recurring charges, no feature gates, no price surprises.
The Designer's Knife is a single-file knife with 9 tools that runs entirely in your browser. The Designer's Knife puts nine essential design utilities plus a live preview Showroom into a single HTML file. Convert between color formats, check WCAG contrast compliance, build harmonious palettes, generate CSS gradients (linear, radial, conic), edit Bézier curves visually, build typographic scales from modular ratios, calculate spacing systems (linear, powers, Fibonacci), paint pixel art on a grid, and preview everything together in the Showroom — a live component gallery that renders your design system as buttons, cards, and typography in real time. All offline, all private, all yours forever.
WHAT'S INSIDE
9 tools in a single HTML file
WCAG Contrast Checker
Test foreground/background colour pairs against WCAG 2.1 AA and AAA contrast requirements. See pass/fail for normal and large text.
Palette Builder
Generate harmonious colour palettes — complementary, analogous, triadic, split-complementary, monochromatic, and tetradic — from any starting colour.
Gradient Generator
Build linear, radial, and conic CSS gradients visually. Add colour stops, adjust angles, and copy the CSS with one click.
HOW IT WORKS
Three steps. No setup.
1
Download the file
Purchase The Designer's Knife and download a single HTML file. No installer, no account, no setup.
2
Open in any browser
Double-click to open in Chrome, Firefox, Safari, or Edge. Works on any operating system.
3
Start working
Your data stays in your browser's local storage. Nothing is uploaded. Ever.
COMPLIANCE & GEOGRAPHY
Global
Works in any country. No server dependency, no regional restrictions.
FAQ
Frequently Asked Questions
How does The Designer's Knife solve the subscription fatigue problem?
The Designer's Knife runs entirely in your browser. Monthly fees for software you already paid to learn. Price hikes you can't avoid. Features removed behind higher tiers. One-time purchase, lifetime access. No recurring charges, no feature gates, no price surprises. Color converter, WCAG contrast checker, palette builder, gradient generator, Bézier editor, type scale, spacing calculator, pixel grid painter, and a live Showroom that previews your entire design system. Your design toolkit in one file.
Is my data safe with The Designer's Knife?
Yes. The Designer's Knife is a single HTML file. It never connects to any server. Your data stays in your browser's local storage on your device.
What makes The Designer's Knife different from cloud tools?
Cloud tools require internet, charge subscriptions, and store your data externally. The Designer's Knife is a one-time purchase ($39), works offline, and never transmits data.
Is The Designer's Knife really just one file?
Yes. The Designer's Knife is a single HTML file containing 9 tools. Download it, open it in any browser, and start working. No installation, no dependencies, no accounts.
No cloud One fileOne-time purchase
Get The Designer's Knife — $39Sovereignty as a Service