AI Avatar Video Agent
Free
New
AI Avatar Video Agent
Build conversational AI avatar apps faster with Next.js and HeyGen integration.
Next.jsTailwindTypeScriptAIHeyGen
FreeAI avatar templates
AI avatars,
conversational by default.
Real-time avatar video, streaming voice, OpenAI integration, and a clean Next.js 15 base — the starter for building AI video products that actually feel alive.
1 template
HeyGen streaming API
OpenAI ready
Free & open source
AI avatars went from research demos to production interfaces in about eighteen months. HeyGen, Synthesia, and D-ID now expose real-time streaming APIs where a customer types or speaks and an avatar responds with lip-synced video at near-zero latency. The technology has matured. The integration plumbing has not — documentation is sparse, sample code is incomplete, and the WebRTC handshake is genuinely hard to get right the first time.
The AI Avatar Video Agent template solves that. It’s a Next.js 15 application with the HeyGen streaming SDK wired up correctly: token generation on the server, WebRTC negotiation in the client, voice activity detection, push-to-talk and continuous modes, transcript history, and a clean UI that doesn’t make your demo look like a debug console. OpenAI integration is layered on top so the avatar can respond to LLM-generated text.
It’s free and MIT-licensed because the moat in AI products isn’t the boilerplate — it’s the prompts, the persona, and the integrations. If you’re building an AI customer support agent, an interactive sales demo, an AI tutor, or an avatar for accessibility, this is the right starting point. Pair it with a SaaS template if you need billing and accounts.
Available Templates
Browse conversational by default.
What you get
Production-grade features, batteries included
HeyGen streaming SDK
Server-side token generation, WebRTC negotiation, voice activity detection, and lip-synced avatar video at sub-300ms latency. The plumbing that takes a week to get right, done correctly.
OpenAI / Anthropic ready
LLM integration is behind a thin adapter — swap OpenAI for Anthropic, Mistral, or your own fine-tuned model with one provider swap. Streaming tokens to the avatar work out of the box.
Voice + text input
Push-to-talk, hold-to-talk, and continuous voice mode. Web Speech API for browser transcription with a Whisper fallback for accuracy. Visual VU meter and waveform feedback for users.
Transcript history
Every conversation is captured client-side with timestamps and speaker attribution. Optional persistence to Supabase or your own backend for replay and analytics.
Custom avatars
HeyGen’s custom avatar feature is wired up — upload a 2-minute recording, train a personal avatar, and swap the avatar ID in your env vars. The rest of the UI follows.
Mobile-ready WebRTC
Works on iOS Safari and Android Chrome with the same code path. Handles connection drops, network changes, and background tabs gracefully — not just on a laptop in your office.
Who it's for
Built for teams that ship
01
AI customer support
Replace a chat widget with a video avatar that handles tier-one support. The avatar greets the customer, asks scoping questions, and escalates to a human only when the LLM hits a confidence threshold.
02
Interactive sales demos
Let prospects talk to a virtual SDR that walks them through your product. Personalised by industry, available 24/7, and qualified leads route straight into your CRM with a transcript attached.
03
AI tutors & coaches
Language tutors, executive coaches, mock interview practice. The avatar provides face-to-face feedback that feels more present than a chat transcript — and is available on demand.
Comparison
How DevKit compares
| Feature | DevKit | HeyGen Direct | Synthesia | D-ID |
|---|---|---|---|---|
| Free starter code | ||||
| Next.js 15 + TypeScript | ||||
| Real-time streaming | Coming | |||
| LLM integration included | DIY | Limited | DIY | |
| Voice input UI | DIY | DIY | ||
| Custom avatar support | ||||
| Transcript persistence | ||||
| Mobile-ready | Web SDK only | Partial | ||
| MIT licensed | ||||
| Self-hosted UI |
FAQ
Common questions
Do I need a HeyGen account to use this?
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Yes. The template uses HeyGen’s streaming avatar API, which requires a HeyGen account and API key. The free tier includes enough credits for development and a small demo. Production usage is billed by HeyGen per minute of streamed video.
Can I use a different avatar provider?
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The template is built around HeyGen because their streaming API is currently the most production-ready. The avatar provider is behind a small interface in the lib folder — swapping in D-ID or Tavus is a 1-day port. Synthesia’s real-time API is in beta; we’ll add an adapter when it’s GA.
What LLM does it use?
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OpenAI GPT-4o by default with streaming responses. Swap to Anthropic Claude, Mistral, or a local model by changing the provider in lib/llm. Function calling and tool use are wired through cleanly.
How much does it cost to run?
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Most of the cost is the avatar video itself — HeyGen charges per minute of streamed video. LLM costs are the standard provider rates. Vercel hosting is free at low scale and pay-as-you-go above the hobby plan. A reasonable estimate is $0.50–$2 per 5-minute conversation.
Is this production-ready?
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The infrastructure is. The product layer (your prompts, persona, knowledge base, fallback flows, abuse handling, rate limits, billing if applicable) is where you add your value. Treat the template as the WebRTC + LLM plumbing solved — the rest is your moat.
Can I add custom training data?
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Yes. The recommended path is to use OpenAI’s assistant API or a retrieval pipeline (e.g., Pinecone, Supabase pgvector) for your knowledge base. The template ships with a RAG starter that you can extend with your documents.
Related categories
Custom builds
Building an AI product?
We’ve shipped production AI avatar apps — customer support, tutoring, sales. Bring us in for a focused build sprint to ship faster.