AI Tutor Demo

AI-powered language tutor built with dTelecom voice agents. Students join a real-time voice session and practice conversational skills with an AI tutor.

Built with:

• @dtelecom/agents-js — voice agent SDK (STT + LLM + TTS pipeline)
• Next.js 16 — app router + API routes
• Deepgram — speech-to-text
• OpenRouter — LLM (GPT-4.1 Mini by default)
• Cartesia — text-to-speech

Deploy to Railway

Required environment variables

Variable	Description
API_KEY	dTelecom API key (cloud.dtelecom.org)
API_SECRET	dTelecom API secret
DEEPGRAM_API_KEY	Deepgram API key (deepgram.com)
OPENROUTER_API_KEY	OpenRouter API key (openrouter.ai)
CARTESIA_API_KEY	Cartesia API key (cartesia.ai)

Optional

Variable	Default	Description
LLM_MODEL	openai/gpt-4.1-mini	OpenRouter model ID
CARTESIA_VOICE_ID	a0e99841-...	Cartesia voice ID

Deploy to a server (Docker + SSL)

Requires a VPS with Docker installed and a domain pointing to it.

# 1. Clone & configure
git clone https://github.com/dTelecom/ai-tutor-demo.git
cd ai-tutor-demo
cp .env.example .env
# Fill in your API keys in .env

# 2. Set your domain in nginx.conf
sed -i 's/YOUR_DOMAIN/yourdomain.com/g' nginx.conf

# 3. Get SSL certificate
# Temporarily comment out the HTTPS server block in nginx.conf, then:
docker compose up -d nginx
docker compose run --rm certbot certonly --webroot -w /var/www/certbot -d yourdomain.com
# Uncomment the HTTPS server block back

# 4. Start everything
docker compose up -d

# 5. Auto-renew SSL (add to crontab -e)
# 0 3 * * 1 cd /path/to/ai-tutor-demo && docker compose run --rm certbot renew && docker compose exec nginx nginx -s reload

Run locally

# 1. Clone
git clone https://github.com/dTelecom/ai-tutor-demo.git
cd ai-tutor-demo

# 2. Install
npm install

# 3. Configure
cp .env.example .env
# Fill in your API keys in .env

# 4. Run
npm run dev

Open http://localhost:3001, pick a lesson, and start talking.

License

Apache-2.0