Learn Morse. Hear the signal. Build the skill.
An offline-first Morse code learning platform for structured lessons, deliberate practice, audio tools, games, and progress tracking.
Relay is a browser-based Morse code learning environment built around a repeatable loop: learn a signal, practise recognition or transmission, review difficult material, and use progress history to guide the next session.
It goes beyond a simple text-to-Morse converter by bringing lessons, practice drills, games, audio decoding, a reference encyclopedia, and personal progress into one installable Progressive Web App (PWA).
Project status: The source code, screenshots, and demo recording are available in this repository. The hosted demo and static landing page are linked above; build and deployment behavior can vary by hosting environment.
| Area | What it offers |
|---|---|
| Learn | Incremental character learning, Koch-style progression, mnemonic aids, and signal exploration |
| Practice | Speed, endless, flashcard, hear-and-type, memory, read-and-type, and translation drills |
| Games | Morse Invaders, Signal Rush, Decode & Translate, Morse Match, and Emergency Relay |
| Translator | Text/Morse conversion, custom dictionaries, and export tools |
| Audio tools | Audio-file decoding, signal analysis, Morse audio playback, and WAV generation |
| Progress | XP, levels, streaks, badges, character mastery, review scheduling, mistake tracking, and WPM trends |
| Reference | Searchable character information and prosigns |
| Personalisation | Multiple interface languages, light/dark themes, audio and timing controls, and accessibility preferences |
| Offline-first design | PWA installation and cached app resources after the app has been loaded successfully |
| Data portability | Browser-local persistence and JSON backup/import tools |
| Optional AI helper | User-configured provider integration; separate from the core local learning workflow |
Feature availability and browser behavior can vary by environment. Audio decoding depends on recording quality and signal conditions; it should not be treated as guaranteed for every file.
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Relay is designed to work without a Relay account or application-owned backend in the supplied source. Application data is primarily stored in the browser, and backup/export tools are available for portability.
Important distinctions:
- Browser-local storage is associated with the browser profile and origin; clearing site data can remove it.
- Private/incognito sessions, browser storage limits, and device loss can affect persistence.
- Optional AI features require network access and send the relevant request to the provider configured by the user. Review that provider's policies before enabling it.
- Do not place secrets, passwords, or sensitive personal information in custom dictionaries, prompts, or backups.
- This repository's privacy guide describes the intended behavior and should be checked against the exact release build.
Read Privacy & data for more detail.
The supplied project is built with:
- React and TypeScript
- Vite
- Tailwind CSS
- React Router
- i18next / react-i18next
- IndexedDB utilities through idb
- Vitest and Testing Library
- Vite PWA tooling
The exact scripts and dependency versions are recorded in package.json and package-lock.json.
Prerequisites: a current Node.js LTS release compatible with the Vite version in the lockfile, plus npm.
git clone https://github.com/mh3nj/Relay.git
cd Relay
npm ci
npm run devVite prints the local development URL in the terminal. Open that URL in a modern browser.
npm run dev # Start the local development server
npm run build # Type-check and create a production build
npm run preview # Preview the production build locally
npm test # Run the test suite once
npm run test:watch
npm run lintRun verification from a clean checkout before treating a build as release-ready. Results may depend on the installed Node.js/npm versions and the environment.
npm ci
npm run build
npm test
npm run lintThe production output is generated in dist/ and is not intended to be committed. Deployment needs to serve the built files and correctly handle client-side routes; verify direct-route refreshes, PWA behavior, and offline reloads on the actual hosting provider.
Use Relay's in-app backup/export controls to keep a separate copy of important learning data. Store exported backups somewhere safe: browser storage is not a substitute for a backup, and imported JSON should only come from sources you trust.
The codebase separates user-interface features from reusable learning, audio, and persistence logic. Relevant areas include:
src/lib/— Morse utilities, learning/practice logic, progress, backup, audio, and related helperssrc/components/— reusable UI componentssrc/i18n/— locale setup and translation resourcespublic/— static assets and PWA resources
These paths are an orientation guide, not a guarantee that every feature is isolated to a single module.
Relay includes multiple locale resources, including right-to-left language support. Translation completeness and accessibility should be validated against the actual UI, keyboard navigation, screen-reader behavior, zoom, and reduced-motion preferences before each release.
Relay is source-available under a custom personal-use and non-commercial sharing license. This is not an OSI-approved open-source license.
The license permits personal learning, private modifications, and conditional non-commercial sharing. Commercial use, paid hosting, and commercial redistribution require prior written permission from the copyright holder.
Read LICENSE before using, copying, modifying, or sharing the project. Third-party dependencies and assets may have separate terms; see Third-party notices. The custom license should receive qualified legal review before being relied on for enforcement.
Commercial licensing: [email protected].
Contributions are welcome for review, but submission does not guarantee acceptance. Read CONTRIBUTING.md before opening a pull request. Keep changes focused, explain the problem being solved, and include tests where appropriate.
Please do not publish exploitable vulnerabilities, API keys, or private user data in public issues. See SECURITY.md for the reporting process.
Use GitHub Issues for reproducible bugs and feature suggestions. Include browser/OS details and clear reproduction steps, but remove personal data and secrets from reports.