LocalMode
Chrome AI

Overview

Zero-download, instant AI inference via Chrome built-in Gemini Nano

@localmode/chrome-ai

Zero-download, instant AI inference via Chrome's built-in Gemini Nano model. No model downloads, no bundle size impact, no API keys — the model ships with the browser.

See it in action

Try Smart Writer for a working demo using Chrome AI with automatic fallback to transformers.

Features

  • Zero model downloads — Gemini Nano ships with Chrome
  • Zero bundle size impact — browser-native APIs
  • Instant inference — no model loading delay
  • Implements SummarizationModel, TranslationModel, and LanguageModel from @localmode/core
  • Feature detection utilities for graceful fallback

The LanguageModel implementation wraps Chrome 138+ window.LanguageModel (the Prompt API) so generateText(), streamText(), generateObject(), and the useGenerateText() / useStreamText() / useModelWarmup() React hooks work on Gemini Nano with zero changes from any other provider.

Installation

pnpm add @localmode/chrome-ai @localmode/core
npm install @localmode/chrome-ai @localmode/core
yarn add @localmode/chrome-ai @localmode/core
bun add @localmode/chrome-ai @localmode/core

Quick Start

import { summarize } from '@localmode/core';
import { chromeAI } from '@localmode/chrome-ai';

const { summary } = await summarize({
  model: chromeAI.summarizer(),
  text: 'Long article text...',
});

console.log(summary);

Comparison

AspectChrome AITransformers.jsWebLLM
First inferenceInstantAfter model download (50MB–2GB)After model download (1–4GB)
Bundle size0 bytes~2MB (WASM runtime)~1MB
Model downloadNoneRequiredRequired
Browser supportChrome 138+ onlyAll browsersChrome/Edge (WebGPU)
OfflineYes (native)Yes (after cache)Yes (after cache)
Model qualityGood (Gemini Nano)Varies by modelHigh (larger models)

Available APIs

APIStatusLocalMode InterfaceChrome Version
SummarizerStableSummarizationModel138+
TranslatorStableTranslationModel138+
Prompt APIStableLanguageModel138+
WriterOrigin trial——
RewriterOrigin trial——

All three stable APIs (Summarizer, Translator, Prompt) are supported by @localmode/chrome-ai. The Prompt API exposes Gemini Nano text generation via chromeAI.languageModel() — see the Language Model guide.

Requirements

Chrome AI is only available on desktop browsers. Mobile (Android/iOS) and Incognito mode are not supported.

RequirementDetail
BrowserChrome 138+ (or Edge 138+)
OSWindows 10+, macOS 13+ (Ventura), Linux, ChromeOS (Chromebook Plus)
Disk space22 GB free on the volume containing your Chrome profile
HardwareGPU with >4 GB VRAM, or CPU with 16 GB+ RAM and 4+ cores

Enabling Chrome AI

  1. Navigate to chrome://flags/#optimization-guide-on-device-model and set to Enabled
  2. Navigate to chrome://flags/#prompt-api-for-gemini-nano and set to Enabled
  3. For higher-quality summaries: chrome://flags/#summarization-api-for-gemini-nano → Enabled with Adaptation
  4. Restart Chrome
  5. Gemini Nano downloads automatically in the background (~1.5 GB)
  6. Verify in DevTools Console:
// Check if Summarizer is ready
await Summarizer.availability(); // "readily" = ready, "after-download" = downloading

// Check if Translator is ready
const caps = await Translator.availability({ sourceLanguage: 'en', targetLanguage: 'es' });

If availability() returns "after-download", the model is still downloading. Creating a session with create() requires a user activation (click, tap, or keypress) to trigger the download.

Provider Factory

import { createChromeAI, chromeAI } from '@localmode/chrome-ai';

// Default instance
const summarizer = chromeAI.summarizer();
const translator = chromeAI.translator({ targetLanguage: 'de' });
const llm = chromeAI.languageModel({ systemPrompt: 'You are concise.' });

// Custom instance
const provider = createChromeAI();
const customSummarizer = provider.summarizer({ type: 'key-points', format: 'markdown' });

Feature Detection

import {
  isChromeAISupported,
  isPromptAPISupported,
  isSummarizerAPISupported,
  isTranslatorAPISupported,
} from '@localmode/chrome-ai';

if (isChromeAISupported()) {
  console.log('Chrome AI is available');
}

if (isPromptAPISupported()) {
  console.log('Prompt API (LanguageModel) is ready');
}

if (isSummarizerAPISupported()) {
  console.log('Summarizer API is ready');
}

Next Steps

Language Model

Generate text with Gemini Nano via the Prompt API

Summarization

Summarize text with configurable type, format, and length

Translation

Translate text between languages instantly

Fallback Patterns

Graceful degradation for non-Chrome browsers

Showcase Apps

AppDescriptionLinks
Smart WriterChrome AI summarization and translation with automatic transformers fallbackDemo · Source

Text Tasks

MediaPipe text tasks in the browser — language detection across 110 languages, semantic text embeddings, and custom-model text classification.

Language Model

Generate text with Chrome built-in Gemini Nano via the Prompt API

On this page

@localmode/chrome-aiFeaturesInstallationQuick StartComparisonAvailable APIsRequirementsEnabling Chrome AIProvider FactoryFeature DetectionNext StepsShowcase Apps