firebase-ai-logic
Client-side Gemini integration for web apps with multimodal inference, streaming, and on-device hybrid execution.
- Supports text-only and multimodal inputs (images, audio, video, PDFs); files over 20 MB route through Cloud Storage
- Includes chat sessions with automatic history, streaming responses for real-time display, and structured JSON output enforcement
- Offers hybrid on-device inference via Gemini Nano in Chrome, with automatic fallback to cloud execution
- Requires App Check for production security and supports dynamic model versioning through Remote Config to avoid redeployment
- Choose between Gemini Developer API (free tier, prototyping) or Vertex AI Gemini API (enterprise scale, requires Blaze plan)
Firebase AI Logic Basics
Overview
Firebase AI Logic is a product of Firebase that allows developers to add gen AI to their mobile and web apps using client-side SDKs. You can call Gemini models directly from your app without managing a dedicated backend. Firebase AI Logic, which was previously known as "Vertex AI for Firebase", represents the evolution of Google's AI integration platform for mobile and web developers.
It supports the two Gemini API providers:
- Gemini Developer API: It has a free tier ideal for prototyping, and pay-as-you-go for production
- Vertex AI Gemini API: Ideal for scale with enterprise-grade production readiness, requires Blaze plan
Use the Gemini Developer API as a default, and only Vertex AI Gemini API if the application requires it.
Setup & Initialization
Prerequisites
- Before starting, ensure you have Node.js 16+ and npm installed. Install them if they aren’t already available.
- Identify the platform the user is interested in building on prior to starting: Android, iOS, Flutter or Web.
- If their platform is unsupported, Direct the user to Firebase Docs to learn how to set up AI Logic for their application (share this link with the user https://firebase.google.com/docs/ai-logic/get-started)
Installation
The library is part of the standard Firebase Web SDK.
npm install -g firebase@latest
If you're in a firebase directory (with a firebase.json) the currently selected project will be marked with "current" using this command:
npx -y firebase-tools@latest projects:list
Ensure there's at least one app associated with the current project
npx -y firebase-tools@latest apps:list
Initialize AI logic SDK with the init command
npx -y firebase-tools@latest init # Choose AI logic
This will automatically enable the Gemini Developer API in the Firebase console.
More info in Firebase AI Logic Getting Started
Core Capabilities
Text-Only Generation
Multimodal (Text + Images/Audio/Video/PDF input)
Firebase AI Logic allows Gemini models to analyze image files directly from your app. This enables features like creating captions, answering questions about images, detecting objects, and categorizing images. Beyond images, Gemini can analyze other media types like audio, video, and PDFs by passing them as inline data with their MIME type. For files larger than 20 megabytes (which can cause HTTP 413 errors as inline data), store them in Cloud Storage for Firebase and pass their URLs to the Gemini Developer API.
Chat Session (Multi-turn)
Maintain history automatically using startChat.
Streaming Responses
To improve the user experience by showing partial results as they arrive (like a typing effect), use generateContentStream instead of generateContent for faster display of results.
Generate Images with Nano Banana
- Start with Gemini for most use cases, and choose Imagen for specialized tasks where image quality and specific styles are critical. (Example: gemini-2.5-flash-image)
- Requires an upgraded Blaze pay-as-you-go billing plan.
Search Grounding with the built in googleSearch tool
Supported Platforms and Frameworks
Supported Platforms and Frameworks include Kotlin and Java for Android, Swift for iOS, JavaScript for web apps, Dart for Flutter, and C Sharp for Unity.
Advanced Features
Structured Output (JSON)
Enforce a specific JSON schema for the response.
On-Device AI (Hybrid)
Hybrid on-device inference for web apps, where the Firebase Javascript SDK automatically checks for Gemini Nano's availability (after installation) and switches between on-device or cloud-hosted prompt execution. This requires specific steps to enable model usage in the Chrome browser, more info in the hybrid-on-device-inference documentation.
Security & Production
App Check
Recommended: The developer must enable Firebase App Check to prevent unauthorized clients from using their API quota. see App-check recaptcha enterprise.
Remote Config
Consider that you do not need to hardcode model names (e.g., gemini-flash-lite-latest). Use Firebase Remote Config to update model versions dynamically without deploying new client code. See Changing model names remotely
Initialization Code References
| Language, Framework, Platform | Gemini API provider | Context URL |
|---|---|---|
| Web Modular API | Gemini Developer API (Developer API) | firebase://docs/ai-logic/get-started |
Always use the most recent version of Gemini (gemini-flash-latest) unless another model is requested by the docs or the user. DO NOT USE gemini-1.5-flash