Guide
How to build a Hindi voice bot
Create an agent in Crackle with its language set to Hindi or Hinglish, pick a voice recorded in Hindi, and write its instructions the way you want it to speak. Switch on its language tool so it follows callers into English and back. Talk to it in your browser, then put it on your website or in your app.
What you need.
- A Crackle account; it is free to start.
- For the API route: a workspace API key (
ck_…) from the studio.
Step by step.
- Choose Hindi or HinglishHindi is for callers who speak it throughout. Hinglish is Hindi with English words mixed in, the way it is commonly spoken in cities; choose it when callers move between the two in one sentence.
- Pick a voice recorded in HindiIn the studio, choose the language and listen to voices before you pick. Sarvam’s Bulbul voices are recorded in Hindi in styles from customer care to news reading, and some speak English and Hindi together; Cartesia Sonic and Rumik Mulberry speak Hindi too.
- Write how it should speakSay it in the instructions: Hinglish with everyday English words, short sentences, warm. Each reply is written in देवनागरी before the voice speaks it.
- Or create it with one requestThe same agent through the API. Set
stt.languagetoo, so it listens for Hindi; the studio does that for you.changeLanguagelets it move between Hindi and English with the caller, andVOICE_IDcomes from the voice library.Request
curl -X POST "https://goblins-call-api.onrender.com/v1/agents" \ -H "Authorization: Bearer $CRACKLE_API_KEY" \ -H "Content-Type: application/json" \ -d '{ "name": "Tara", "systemInstruction": "You are Tara, and you answer calls for Sunrise Dental in Jaipur.\nSpeak Hinglish: everyday Hindi with the English words people really use, such as appointment, doctor and confirm.\nBe warm and brief. One or two short sentences per reply.\nIf the caller switches to English, switch with them, and switch back when they do.", "greetingInstruction": "Greet the caller warmly in Hinglish and ask how you can help.", "voice": { "language": "hinglish", "speaker": "VOICE_ID" }, "stt": { "language": "hi" }, "systemTools": { "changeLanguage": true, "endCall": true } }' - Talk to it, then ship itPress Test agent in the studio and have the conversation your callers will have. Then add the call button to your website, or start calls from your app.
All of it, in the docs.
The worked example has every file, and the guide explains each part.
Questions.
Will it understand English words in a Hindi sentence?
Yes. Every agent listens for English as well as its own language.
Can it switch to English completely?
Yes. With the language tool on, when a caller moves to English the agent moves with them and stays there for the rest of the call.
Can it speak other Indian languages too?
Yes: Tamil, Telugu, Kannada, Marathi, Bengali, Gujarati and Punjabi have voices recorded in them, and an agent with a Cartesia or Sarvam voice and GPT Transcribe or Saaras transcription can hold a single call in any of them.
Other guides.
How to add a voice agent to your website
Make an agent in Crackle’s studio, switch on its call button and paste one line of HTML before </body>. Visitors press it and talk to your agent, with no server of your own.
Read the guideHow to build a voice agent in Next.js
A route handler that starts a Crackle call with your API key, and a client component that joins it with livekit-client. Two files; the key never reaches the browser.
Read the guideHow to add a voice agent to a React Native app
Your server starts a Crackle call with one request; your Expo or React Native app joins it with LiveKit’s React Native SDK, with mute and hang up.
Read the guideGive your agent a voice today.
Build one in the studio and talk to it in your browser. Sign-up credit is there for your first test calls.