The latest articles on DEV Community by JOHN KHORE 5911 (@john_khore5911_585a2c0c4). https://dev.to/john_khore5911_585a2c0c4 https://media2.dev.to/dynamic/image/width=90,height=90,fit=cover,gravity=auto,format=auto/https:%2F%2Fdev-to-uploads.s3.us-east-2.amazonaws.com%2Fuploads%2Fuser%2Fprofile_image%2F4174466%2F848dde66-65dd-44e0-9b5c-33047b5f0bbf.png https://dev.to/john_khore5911_585a2c0c4 en JOHN KHORE 5911 Sat, 10 Oct 2026 03:11:41 +0000 https://dev.to/john_khore5911_585a2c0c4/i-built-an-app-that-translates-whatsapp-voice-notes-and-lets-you-reply-by-voice-in-their-language-3hbc https://dev.to/john_khore5911_585a2c0c4/i-built-an-app-that-translates-whatsapp-voice-notes-and-lets-you-reply-by-voice-in-their-language-3hbc <p>My family sends voice notes. A lot of them. Two minutes of Punjabi from my mom, a quick one in Hindi from an uncle, and I understand maybe half of it.</p> <p>WhatsApp can now transcribe voice messages on some phones, but only into text in the <strong>same</strong> language. That doesn't help when the problem is the language itself. And typing my reply into Google Translate, then pasting back text they won't read anyway (they prefer voice), never felt right.</p> <p>So I built <strong><a href="https://www.replylingo.com" rel="noopener noreferrer">ReplyLingo</a></strong>, a small app for iPhone and Android that does three things:</p> <ol> <li> <strong>Understand.</strong> Share a voice note from WhatsApp or Telegram into the app. It transcribes it and translates it into your language.</li> <li> <strong>Listen.</strong> It can read the translation out loud.</li> <li> <strong>Reply by voice.</strong> Record your answer in your own language, and the app turns it into a voice message in <strong>their</strong> language that you send straight back.</li> </ol> <p>That third part is the one people react to. Parents hear a voice reply in their own language instead of a block of English text.</p> <h2> The stack </h2> <p>Nothing exotic, but a few choices might help other solo builders:</p> <ul> <li> <strong>Expo / React Native</strong> for one codebase on iOS and Android. The share-sheet integration (receiving an audio file from WhatsApp) took the most fiddling on both platforms.</li> <li> <strong>Whisper</strong> for speech-to-text. It handles messy, real-life voice notes (background noise, mixed languages) better than anything else I tried.</li> <li> <strong>An OpenAI model for translation.</strong> It keeps tone and casual phrasing much better than word-by-word translation, which matters for family chat.</li> <li> <strong>Google Cloud Text-to-Speech</strong> for the voice reply, with <strong>ElevenLabs as a fallback</strong> when a language or voice isn't supported.</li> <li> <strong>Firebase</strong> for auth, <strong>RevenueCat</strong> for subscriptions on both stores.</li> </ul> <h2> Things I learned </h2> <p><strong>1. "Translate" means different things to different users.</strong> Some only want text in their language. Others mostly want to reply.</p> <p><strong>2. Store listings matter more than I expected.</strong> People looking for an app like this search the App Store and Play Store, not Google, so I localized both store pages (keywords, descriptions, screenshots) into many languages.</p> <p><strong>3. TTS fails in surprising ways.</strong> Some language and voice combinations just don't exist in one provider. A fallback provider saved a lot of broken replies.</p> <p><strong>4. Free trials are not automatically good.</strong> After I added a 3-day trial, people who used to buy straight away started a trial instead. I'm still testing the right setup.</p> <h2> Try it </h2> <p>ReplyLingo is free to start on the App Store and Google Play. More at <strong><a href="https://www.replylingo.com" rel="noopener noreferrer">replylingo.com</a></strong>.</p> <p>If you've built anything with voice, translation or share-sheet extensions in React Native, I'd love to compare notes in the comments, and I'm happy to answer questions about the stack.</p> reactnative ai showdev mobile