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All Currency Converter

Open-source licences

Last updated: August 30, 2026

All Currency Converter is built on open-source software. This page lists the main components the Android app, this website and the rates API depend on, together with the licence each one is published under, as those licences require.

Most of them are distributed under the MIT licence, and the Android and Kotlin components under the Apache License 2.0. Both permit commercial use and redistribution provided the original copyright notice and licence text are preserved, which is what this page and the licence screen inside the app are for.

Why this page exists

Open-source licences ask anyone who ships software built on them to keep the attribution visible. The list below is that attribution. It names the components a reader would want to check, not every transitive dependency in the build.

The same list is available inside the app, under Settings, so it stays reachable offline. Copyright in each component belongs to its own authors and contributors, not to us.

The mobile app

The Android app is a React Native application built with the Expo toolchain. These are the components that define how it is written and how it behaves.

  • React (MIT licence) - the component model the whole interface is written against.
  • React Native (MIT licence) - renders that interface with native Android views rather than a web view.
  • Expo (MIT licence) - the toolchain, the native modules and the file-based router the app is organised around.
  • React Native Reanimated (MIT licence) - the only animation library in the app; every transition and gesture-driven movement runs on it.
  • React Native Gesture Handler (MIT licence) - the native gesture system behind drag-to-reorder and the bottom sheets.
  • Zustand (MIT licence) - the state stores holding your settings, favourites, alerts and widget configuration.
  • TanStack Query (MIT licence) - fetches and caches the historical rate series behind the charts.
  • NativeWind (MIT licence) - brings Tailwind CSS class names to React Native styling.
  • react-native-mmkv (MIT licence) - the fast key-value storage that keeps your data on the device.
  • react-native-svg (MIT licence) - draws the charts and the sparklines.
  • date-fns (MIT licence) - date formatting and arithmetic for the historical periods.
  • i18next and react-i18next (MIT licence) - the translation layer behind the 20 app languages.
  • Axios (MIT licence) - the HTTP client used to reach our rates API.

The Android home screen widget

The widget is native Android code rather than React Native, because a home screen widget has to render without the app running. It relies on the following.

  • Kotlin (Apache License 2.0) - the language the widget and its native module are written in.
  • Jetpack Glance and the AndroidX libraries (Apache License 2.0) - the widget interface, its background work scheduling and its local storage.
  • OkHttp (Apache License 2.0) - fetches the rates the widget displays when the app is closed.

This website

The site you are reading is statically generated, which is why every page loads as finished HTML rather than as an empty shell waiting for scripts.

  • Next.js (MIT licence) - the framework that generates these pages ahead of time and serves the browser converter.
  • React and React DOM (MIT licence) - the component model shared with the mobile app.
  • Tailwind CSS (MIT licence) - the styling system behind the layout, the typography and the dark theme.
  • PostCSS and Autoprefixer (MIT licence) - the stylesheet build pipeline.
  • TypeScript (Apache License 2.0) - the language the site, the app and the API are written in.

The rates API

A small server of our own sits between the rate provider and everything else, so that one hourly request serves every page and every installation instead of each of them calling the provider directly.

  • Hono (MIT licence) - the web framework the API routes are built with.
  • Cloudflare Workers types and tooling (MIT licence) - the runtime typings and the deployment tooling for that server.

Services that are not open source

Some components of the app are proprietary software distributed under their vendors' own terms rather than an open-source licence. They are listed here for completeness, because their presence in the app is a fact worth knowing.

The Google Mobile Ads SDK, which serves the advertising in the free version, and the Firebase SDKs for analytics, crash reporting and push notifications, are supplied by Google under the Google APIs Terms of Service and the Firebase terms. Google Play Billing handles purchases under the Google Play Developer Distribution Agreement. The RevenueCat SDK is published under the MIT licence, but the entitlement service behind it is a commercial product governed by RevenueCat's own terms.

Exchange rate data

The exchange rates shown in the app, on this website and on the home screen widget are supplied by ExchangeRate-API and refreshed hourly. We are grateful for the service and we credit it on every page that publishes a figure derived from it.

The rates are mid-market rates provided for information only. They are not a quote, and the rate a bank or a bureau de change applies to you will differ.

Full licence texts

The complete text of the MIT licence and of the Apache License 2.0, together with the copyright notice of each component, ships inside the app and can be read from the licences entry in Settings. Each project also publishes its licence in its own repository.

If you need a specific notice in writing, or you believe a component is listed under the wrong licence or is missing from this page, write to support@codeurdivoire.com and we will correct it in the next release.

Trademarks

Android, Google Play, Google Drive, Firebase and AdMob are trademarks of Google LLC. Other product names, logos and marks mentioned on this page belong to their respective owners. Their use here identifies the software concerned and implies no affiliation with, or endorsement by, those owners.