Decrypting Morse Code in the Browser: How I built a privacy-first audio decoder

The Problem: Cloud-based Decoders vs. Privacy

Most Morse code tools are either outdated Windows-only apps or web tools that require you to upload your audio files to a remote server. As someone who values privacy, I wanted a solution where the audio never leaves the device.

That’s why I built MorseDecode (https://www.morsedecode.xyz).

The Core Feature: Real-time Recording & Decryption

The most challenging (and rewarding) part was building the Audio-to-Text pipeline. Here is how it handles recordings:

• Direct Audio Capture: It records live signals or processes uploaded WAV, MP3, and OGG files directly in the browser using the Web Audio API.
• Local Decryption: The decryption engine runs 100% on the client side, extracting messages from audio pulses without any server-side processing.
• Visual Analysis: Users get real-time waveform visualization, making it easier to see signal quality during the decryption process.
• Adaptive WPM Detection: The tool automatically identifies the speed of the incoming Morse code to handle variations in WPM (Words Per Minute).

Tech Stack

To ensure the decoder was fast and responsive, I used:

• Next.js for the framework.
• Tailwind CSS for a clean, professional signal-processing UI.
• Web Audio API for high-accuracy local audio analysis.
• GitHub for hosting our open-source repository and community collaboration.

Support us on Product Hunt! 🚀

We just launched on Product Hunt! If you’re into ham radio, signal processing, or open-source dev tools, I’d be honored to have your support and feedback.

Check us out here: 👉 https://www.producthunt.com/posts/morse-decoder

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Find us on GitHub: morsedecode/MorseDecode-Audio-Decoder