# WebNN API The Web Neural Network API — a W3C specification for running neural network models directly in web browsers with hardware acceleration. Foundation layer of the [[WebMachineLearning]] ecosystem; higher-level APIs (Prompt API, Writing Assistance APIs) build on top of it. Spec repo: https://github.com/webmachinelearning/webnn ## What it does WebNN exposes browser-level access to the device's ML hardware (GPU, NPU) via a JavaScript API. Developers can: - Build, compile, and execute computation graphs for neural networks - Leverage hardware-specific optimizations without writing platform-specific code - Run inference on models without a server or cloud API ## Design Goals - **Hardware agnostic**: single API works across GPU, NPU, CPU backends - **Cross-browser**: standardized contract; one implementation for all browsers - **Performance**: native hardware acceleration, not a pure JS polyfill - **Low-level**: intentionally primitive — higher-level APIs compose on top of it ## Relationship to Other APIs - **[[Prompt API]]** — uses WebNN or OS model interfaces under the hood - **[[Writing Assistance APIs]]** — Summarizer, Writer, Rewriter compose on WebNN - WebAssembly (WASM): complementary; WebNN focuses on ML-specific hardware paths ## Status W3C Candidate Recommendation. Shipping in Chrome and Edge. Under development in other browsers. ## References - https://github.com/webmachinelearning/webnn - https://www.w3.org/TR/webnn/ ## Related - [[WebMachineLearning]] - [[Prompt API]] - [[Writing Assistance APIs]] - [[Neural Networks (NNs)]] - [[Machine Learning (ML)]] - [[AI Inference]] - [[On-Device Machine Learning]] - [[Browser-Provided Language Models]] - [[WebGPU]] - [[Web Assembly (WASM)]] - [[ONNX]] - [[ONNX Runtime Web]] - [[Transformers.js]] - [[Neural Processing Unit (NPU)]] - [[Edge AI]]