Sahil Sonawane
Jul 4, 2025
How to build agentic apps with Flutter and Firebase AI Logic
Introduction: Agentic Apps Are Here
Let’s be honest—AI in apps has already gone way beyond just “smart suggestions” or basic chatbots. We’re entering a new phase where your app doesn’t just react to input, it acts with purpose. That’s the essence of agentic apps—apps that can reason, make decisions, and perform tasks on the user’s behalf.
Now imagine building such agentic applications with Flutter—without needing to switch languages, juggle APIs, or build your own AI stack from scratch.
That’s exactly what Google showed us in a recent demo using Flutter, Firebase, and Gemini. In this example, a user simply says, “I don’t like this yellow, make it blue,” and the app not only understands the request, but confirms it, updates the UI, and even logs helpful feedback—all by itself.
This blog is your walkthrough on how to build agentic apps just like that. We’ll break down what makes an app “agentic,” how to wire it up using Flutter and Firebase Vertex AI, and how to design thoughtful user experiences that actually feel magical.
By the end of this, you’ll see that developing agentic applications with Flutter isn’t some futuristic dream. It’s entirely doable today—with tools you already use. Whether you want to create agentic apps with Flutter for feedback handling, smart settings, in-app support, or even full voice-based UI, you’re in the right place.
What Powers an Agentic App?
Let’s take a moment to unpack what makes an app agentic. It’s not just about using AI—it’s about giving your app the ability to understand, decide, and act.
A typical app waits for you to tap buttons. But an agentic app? It listens, thinks, and does. It can interpret natural language, reason about what to do next, and use tools built into your app to carry out those actions.
At the heart of any agentic mobile app built with Flutter and Firebase, there are three essential pieces:
1. A Language Model (LLM)
This is what drives reasoning. It could be Gemini, GPT, Claude, or any model you integrate through Firebase Vertex AI or a third-party API. The LLM helps interpret what the user is asking for and suggests the right actions.
2. A Set of Tools (Function Calls)
These are custom functions you define—like changing a theme color, submitting feedback, or showing a confirmation prompt. The LLM chooses which tools to call based on the user’s intent.
3. A Runtime That Executes
Here’s the key: the LLM doesn’t directly execute anything. It recommends actions. Your Flutter app is the one that makes the actual changes—whether it’s updating UI, saving to a database, or invoking an API.
That’s what makes agentic app development in Flutter so powerful. You get the best of both worlds: intelligent reasoning from the LLM and fine-grained control from your app’s logic.
So whether you're working on a support chatbot, an adaptive UI, or an in-app assistant, you’re essentially giving your Flutter app a brain—and a toolkit.
Flutter + Firebase + Vertex AI: The Perfect Stack
If you’re wondering whether building agentic apps in Flutter is going to require learning new languages, APIs, or obscure dev tools—the good news is, you’re already closer than you think.
Let’s break down the stack that makes creating agentic mobile apps with Flutter so accessible:
🚀 Flutter: Your Cross-Platform Powerhouse
You already know it—Flutter lets you build beautiful, performant apps for mobile, web, desktop, and more, all from a single codebase. But more than just UI, Flutter gives you the flexibility to handle logic, function calls, and real-time state changes—perfect for agentic app development in Flutter where your UI may evolve dynamically based on what the agent decides to do.
🔧 Firebase: Your AI-Ready Backend
Firebase isn’t just about auth or crash reporting anymore. When you use Firebase for agentic apps, you’re tapping into secure APIs, serverless functions, App Check, Remote Config, and seamless integration with cloud-hosted AI tools. It’s the scaffolding that supports agentic behavior—handling user feedback, storing device info, and enabling smart responses.
🧠 Vertex AI (SDK): Your Bridge to Any LLM
The Firebase Vertex AI SDK makes it easy to connect your Flutter app to powerful language models like Gemini—or any other LLM supported through Vertex or custom endpoints. This SDK is designed for mobile and web use, giving you access to features like:
Multimodal prompts (text + images)
Function/tool calling
Real-time streaming (via Gemini Live or equivalents)
JSON output and schema enforcement
And the best part? You don’t have to switch languages or deal with complex backend infrastructure. You can develop agentic apps with Flutter entirely within your Dart codebase.
Together, this stack gives you the freedom to build agentic apps with Firebase and Flutter that aren’t just smart—they’re usable, deployable, and maintainable at scale.
Building an Agentic App: Core Steps
Now that we’ve got the “why” and “what” out of the way, let’s talk about the “how.” This is where you actually build agentic apps with Flutter and hook them into your chosen AI logic using Firebase and the Vertex AI SDK.
Don’t worry—if you’ve built any Flutter + Firebase app before, you’ll feel right at home. The difference? You’re now giving your app a brain and a voice.
Here’s a simplified roadmap to get you started with developing agentic applications with Flutter:
Step 1: Set Up Your Firebase + Flutter Project
Create a Firebase project in the console
Enable billing and turn on Vertex AI APIs
In your Flutter project, add these packages:
flutter pub add firebase_core
flutter pub add firebase_vertexai
Run the flutterfire configure command to link your app to Firebase
Step 2: Define Your Agent’s System Prompt and Tools
This is where the “agent” part comes in. In your code, configure the agent with:
A system prompt — defines the agent’s personality and goal.
E.g. “You are a helpful in-app concierge that assists users with UI changes.”A list of tools (function calls) — these are the things your agent can do.
Examples:Change app theme color
Ask user for confirmation
Retrieve device info
File structured feedback reports
Here’s a sample function declaration for changing the app color:
final changeColorTool = FunctionDeclaration(
name: 'change_app_color',
description: 'Changes the app theme color.',
parameters: {
'r': {'type': 'integer', 'description': 'Red value'},
'g': {'type': 'integer', 'description': 'Green value'},
'b': {'type': 'integer', 'description': 'Blue value'},
},
);
Step 3: Capture Feedback with UI
Use the feedback package from pub.dev—it lets users take screenshots, annotate, and describe the issue in natural language. This input is what you’ll send to the LLM.
Perfect for building smart agentic apps using Flutter that learn from user interaction on the fly.
Step 4: Handle LLM Responses and Execute Actions
Once a message is submitted, send it to the LLM using the Vertex SDK’s chat interface. If the response includes function calls, your app should:
Parse the function call
Execute the action (e.g., update state, show dialog)
Send a confirmation or result back to the chat thread
Remember: the model doesn’t execute anything directly—it just tells your app what should be done. Your Flutter logic makes it real.
Key Design Principles for Agentic UX
Just because your app can act autonomously doesn’t mean it should do everything on its own. One of the most important parts of agentic app development in Flutter isn’t just wiring up the logic—it’s designing for real people.
Here are a few critical UX principles to follow when you develop agentic apps with Flutter and Firebase AI:
Always Ask Before Acting
Let’s say the agent wants to change your app’s color from yellow to blue. Don’t just surprise the user with a sudden visual shift—ask for confirmation. Use modal dialogs or snackbars to verify first.
That’s why most agentic apps in Flutter include a tool like ask_user_confirmation()—because the agent is smart, but the user still calls the shots.
Prepare for Imperfect Instructions
Real-world user input is messy. Someone might write, “this font is weird lol”. Your LLM might still figure it out, but you’ll need fallbacks if the response isn’t actionable.
So when the agent can’t execute a tool, the app should default to generating a structured feedback report instead. That way, you’re still learning—even when automation isn’t possible.
Clarity in Function and Parameter Descriptions
When you define a tool for your agent, make it readable. You’re not writing for the machine—you’re writing for the model trying to understand what the tool does.
For instance:
description: 'Updates the app font size. Use for accessibility or readability improvements.'
Well-described tools lead to more accurate and useful agent behavior—core to creating agentic apps with Flutter that feel intentional.
Maintain Chat Context (Session History Matters)
Most LLM-based agents benefit from persistent context. That’s where chat sessions in Vertex AI (or any similar LLM tool) shine. By retaining previous messages, the agent can reason better, follow up, and avoid redundant questions.
If you’re building agentic apps with Flutter, maintaining that session state improves both the intelligence and the user experience.
Keep It Secure, Keep It Private
Remember—agentic mobile apps with Flutter and Firebase can potentially collect and act on sensitive data. Use Firebase App Check to ensure that only legitimate users are triggering AI requests.
You should also be transparent with users: let them know what’s being collected, what’s automated, and where their data is going.
Real Agentic App Ideas You Can Build with Flutter and Firebase
Now that you understand what agentic apps are and how they work, let’s look at what you can actually build. These ideas aren’t sci-fi—they’re very real and doable today using Flutter for agentic app development with Firebase powering the backend and AI logic.
Here are six practical and exciting use cases:
1. Fitness Coach That Adapts to You
An app that reads your daily activity (like steps, sleep, or water intake) and adjusts your workout or meal plan accordingly. It can send nudges, tweak routines, and even highlight patterns—all without manual input.
2. Smart Language Learning Companion
A language learning app that adapts to how you learn. If you struggle with verbs, it gives you more drills. If you ace pronunciation, it levels you up. Think flashcards, quizzes, speaking practice—all adjusted in real time.
3. CRM That Writes and Follows Up
For sales teams or solopreneurs, an app that drafts emails, schedules follow-ups, and summarizes conversations based on lead updates. It becomes your silent assistant who never forgets a lead or a meeting.
4. Maintenance App for Field Technicians
For companies managing equipment or infrastructure, the app can predict issues based on sensor data, assign technicians, and prep parts ahead of time. Techs see their schedule and updates in a live Flutter dashboard.
5. Travel Planner in Your Pocket
Let users describe their dream trip in plain language—"3 days in Kerala, quiet and scenic"—and the app builds the itinerary, books the stay, and stores all tickets in-app. Users can tweak it on the go.
6. Content Assistant for Creators
Upload a video or audio file, and the app automatically creates short clips, writes captions, drafts social posts, and helps schedule them. All edits and previews happen right inside a Flutter app.
These are just starting points. Once you begin creating agentic mobile apps with Flutter, you’ll see how easily you can apply this model to your industry—be it healthcare, edtech, logistics, productivity, or finance.
Final Thoughts + Resources
We’re at a turning point in how apps are built—and how they behave. With the rise of language models, apps are no longer just responsive—they’re becoming proactive, contextual, and truly helpful.
That’s the promise of agentic apps, and the best part is: you don’t need a new tech stack to build them.
With Flutter, you already have a fast, scalable, cross-platform UI toolkit. With Firebase, you’ve got secure backend services that handle storage, auth, messaging, and configuration. And with the AI capabilities now accessible through Firebase, you can build agentic apps with Flutter that think, reason, and act—across web, mobile, and desktop.
Whether you're trying to:
Create agentic apps with Flutter for smarter UX,
Develop agentic applications that adapt in real time,
Or explore ways to build agentic apps with Firebase for enterprise use.
The tools are ready. The ecosystem is stable. And the ideas? You just read six of them—ready to be shipped.
Helpful Links to Get Started
Agentic mobile apps with Flutter and Firebase aren’t just cool—they solve real problems, remove friction, and create experiences that feel personal. And if you're already building with Flutter, this isn’t a leap—it’s a step forward.
Flutternest Leads the Way in Agentic App Development
From dynamic mobile interfaces to fully integrated app agents, we specialize in crafting agentic apps that don’t just respond—they reason, decide, and deliver. Backed by deep expertise in Flutter and Firebase, our team builds AI-native experiences that feel seamless, scalable, and genuinely useful.
Whether you’re imagining the next health companion, support assistant, or smart enterprise workflow—Flutternest brings the vision, engineering muscle, and product thinking to make it real.
