Web LLM (18,517 Stars) In-Browser Inference 2026

WebLLM (18,517 stars) runs LLMs entirely in your browser with WebGPU - no server, no API key. Here is how to load Llama and Qwen models client-side in minutes.

💡 What You Will Learn

WebLLM (18,517 stars) runs LLMs entirely in your browser with WebGPU - no server, no API key. Here is how to load Llama and Qwen models client-side in minutes.

📜 Table of Contents

• The short answer
• Why in-browser inference matters
• Quick start (npm)
• Practical considerations
• FAQ

The short answer

mlc-ai/web-llm (18,517 stars, TypeScript) is a high-performance in-browser LLM inference engine built on WebGPU. It turns your browser tab into a local GPU server: models run on the user hardware, so there is no server cost, no data leaving the device, and no API key.

Why in-browser inference matters

• Zero infrastructure: no backend, no GPU rental, no per-token cost
• Privacy by design: prompts never leave the device
• Offline capable: works with no network after model download
• Scales for free: every visitor brings their own compute

Quick start (npm)

npm install @mlc-ai/web-llm

import * as webllm from "@mlc-ai/web-llm";
const engine = await webllm.CreateEngine("Llama-3.1-8B-Instruct-q4f16_1-MLC");
const reply = await engine.chat.completions.create({
  messages: [{ role: "user", content: "Explain WebGPU in one sentence" }]
});
console.log(reply.choices[0].message.content);

The first load downloads the model (a few GB for 8B quantized) and compiles it with WebGPU; subsequent sessions start in seconds. Smaller models like Qwen2.5-0.5B/1.5B run comfortably on laptops.

Practical considerations

• Requires a WebGPU-capable browser (Chrome/Edge on Windows/Mac, and Linux with flags).
• Model downloads are large - offer a progress UI and cache in IndexedDB.
• For 8B+ models recommend 16 GB RAM; 0.5B-1.5B models run on phones.

FAQ

Is it really free? Yes - compute happens on the visitor device. You pay nothing per request.

Which models are supported? Llama, Qwen, Phi, Gemma and more, with prebuilt WebGPU-optimized checkpoints.

What about Safari? WebGPU support is improving; for older browsers, fall back to a server-side endpoint.

❓ FAQ

Is it really free?

Yes - compute happens on the visitor device. You pay nothing per request.

Which models are supported?

Llama, Qwen, Phi, Gemma and more, with prebuilt WebGPU-optimized checkpoints.

What about Safari?

WebGPU support is improving; for older browsers, fall back to a server-side endpoint.