Curren$or π±
A sleek currency converter you can self-host in seconds. Compare up to 5 currencies at once with live exchange rates, swap them around, search through 50 options. One HTML file, zero setup.
β Try it live Β· β Use it inside Claude or ChatGPT
Use it inside Claude or ChatGPT
Currensor also runs as a plugin (an MCP server) for Claude and ChatGPT. Ask for a conversion in plain words and a live Currensor card appears right in the chat. Change the amount on the card and every currency updates instantly.
Plugin address:
https://currensor-mcp.currensor-mcp.workers.dev/mcp
| App | How to add it |
|---|---|
| Claude | Settings β Connectors β Add custom connector β paste the address β choose No sign-in |
| ChatGPT | Settings β Plugins β Developer mode on, then + β Create custom MCP server β paste the address β No Auth |
Then ask: "Use Currensor to convert 250 CAD to INR, EUR and JPY."
- Live mid-market rates for 166 currencies, refreshed daily, with a backup rate feed
- No sign-in, no API key, nothing about you stored. The server keeps only anonymous daily counts (which app, which currency pair) to see if people find it useful
- Free and open source: the server is in
mcp/and runs on Cloudflare Workers
Features
- Live exchange rates β Updated hourly; the page checks again just after each update, and falls back to two daily public feeds if the hourly service is down
- 50 currencies β Grouped by region (Americas, Europe, Asia & Pacific, Middle East & Africa)
- Multi-currency view β See up to 5 conversions side by side
- Smart swap logic β Picking a currency already in use auto-swaps instead of duplicating
- Drag to reorder β Rearrange your target currencies by dragging the grip handle
- Dark & Light themes β Trading terminal dark mode or clean travel app light mode, saved to your preference
- Shareable conversion cards β Generate a branded PNG image of your conversion to share anywhere
- Export / Copy β One tap copies all conversions with currency symbols, ready to paste into WhatsApp, Slack, or email
- Bottom-sheet picker β Mobile-friendly currency selector with instant search
- Cross-platform flags β Twemoji flag images that render identically on every device
- Graceful fallback β Bundled rates kick in if APIs are unavailable
- Zero dependencies β One HTML file. No frameworks, no build step, no node_modules
How to Use
Option 1: Just open it
git clone https://github.com/Kay0sstheory/Currensor.git
cd Currensor
# Open index.html in your browser
Option 2: GitHub Pages (free hosting) Already live at kay0sstheory.github.io/Currensor
Supported Currencies
Americas: USD, CAD, MXN, BRL, ARS, CLP, COP, PEN Europe: EUR, GBP, CHF, SEK, NOK, DKK, PLN, CZK, HUF, RON, TRY, RUB, UAH, ISK Asia & Pacific: JPY, CNY, INR, KRW, SGD, HKD, TWD, THB, MYR, IDR, PHP, VND, PKR, BDT, LKR, AUD, NZD Middle East & Africa: AED, SAR, QAR, KWD, BHD, ILS, EGP, ZAR, NGN, KES, MAD
Tech Stack
- Pure HTML, CSS, JavaScript β no frameworks, no libraries
- Hourly rates service on Cloudflare Workers (primary, source in
mcp/) + Open Exchange Rates API and Currency API (daily backups) - Twemoji CDN for cross-platform flag rendering
- DM Sans + Space Mono fonts via Google Fonts
- Canvas API for shareable card generation
- Dark/light themes via CSS variables with localStorage persistence
- Mobile-responsive down to 360px viewport
Version History
- v2.2 β Claude & ChatGPT plugin with an in-chat card; refreshed backup rates
- v2.1 β Swap logic fix, drag-to-reorder, cross-platform Twemoji flags, bigger rate text, dark/light theme toggle, shareable conversion cards, export/copy with currency symbols
- v2.0 β Live exchange rates, 50 currencies grouped by region, live status indicator, improved mobile UX
- v1.0 β Initial release with bundled rates and 20 currencies
Roadmap
- Interactive globe for selecting target currencies (v3)
- Historical rate sparkline charts
- Rate heatmap β weekly performance at a glance
- Volatility indicator per currency pair
- Purchasing power comparison
- Shareable URLs with encoded conversion state
- Favorites saved to localStorage
Why I Built This
I'm building tools with AI and learning in public. I can't write code from scratch (yet), but I can design, think through problems, and ship real products by collaborating with AI. Every project teaches me something new.
Follow along: @Kay0sstheory
License
MIT β do whatever you want with it.