A step-by-step guide to running Google's Gemma 4 multimodal model entirely in the browser using Transformers.js, WebGPU, and ONNX Runtime — no Python, Node.js, or backend server required. The tutorial covers building a complete HTML/JS application that loads a quantized (q4f16) ONNX version of Gemma 4, handles image and audio inputs via URL or file upload (using FileReader and Web Audio API), checks for WebGPU support, streams generated tokens in real time with TextStreamer, and caches model weights in the browser for faster subsequent runs.
Table of contents
Running Gemma 4 in the Browser with Transformers.js and WebGPUBuilding a Browser-Based Gemma 4 AI ApplicationCreating the HTML Document and Styling the InterfaceCreating the Application LayoutLoading Transformers.js for Browser-Based Gemma 4 InferenceChecking for WebGPU SupportReferencing the User InterfaceCreating Helper FunctionsPreviewing Images from a URLProcessing Local Image and Audio Inputs for Gemma 4 Multimodal AIProcessing Audio Inputs in the Browser with Web Audio APILoading the Processor and Gemma 4 ModelRunning Gemma 4 Multimodal Inference Directly in the BrowserOutputSummary7 Impressions