Building AI-Powered Flutter Apps with Claude

Introduction

Artificial Intelligence (AI) is transforming how we interact with technology. Instead of hard-coding logic for every feature, developers can now offload tasks like summarization, reasoning, and content generation to Large Language Models (LLMs).

Claude, created by Anthropic, is one of the newest and most powerful AI assistants available today. It competes with models like OpenAI’s GPT, but with a focus on safety, long context handling (up to 200K tokens), and strong reasoning abilities.

In this article, I’ll show how Flutter, a cross-platform framework for mobile development, can integrate with Claude’s API to create AI-driven mobile applications.

Why Use AI in Mobile Apps?

Mobile users generate and consume text constantly — notes, emails, chats, documents, and more. Embedding AI into apps unlocks powerful use cases:

1. Summarization → Turn long text into quick highlights.

2. Chatbots → Build in-app virtual assistants.

3. Content Moderation → Automatically detect unsafe content.

4. Learning Tools → Translate or explain concepts in natural language.

Instead of building complex Natural Language Processing (NLP) pipelines, we can connect to Claude’s API and fetch smart responses instantly

Setting Up Claude API

Claude is accessible via a simple REST API.

• Sign up at Anthropic Console

• Generate an API key.

• Store the key securely — never hard-code it in your Flutter app.

(Best practice: call Claude through your backend.)

Flutter + Claude Integration

In Flutter, we can use the http package to send requests to Claude’s API.

Here’s a simple ClaudeService class:

import 'dart:convert';
import 'package:http/http.dart' as http;

class ClaudeService {
  final String apiKey;

  ClaudeService(this.apiKey);

  Future<String> summarizeText(String input) async {
    final url = Uri.parse("https://api.anthropic.com/v1/messages");

    final response = await http.post(
      url,
      headers: {
        "Content-Type": "application/json",
        "x-api-key": apiKey,
      },
      body: jsonEncode({
        "model": "claude-3-5-sonnet-20240620",
        "max_tokens": 300,
        "messages": [
          {"role": "user", "content": "Summarize this:\n\n$input"}
        ],
      }),
    );

    if (response.statusCode == 200) {
      final data = jsonDecode(response.body);
      return data["content"][0]["text"];
    } else {
      throw Exception("Claude API error: ${response.body}");
    }
  }
}

Demo: Summarizer App

1. Let’s build a quick Summarizer App:

2. User pastes text in a TextField.

3. On button click, Flutter calls ClaudeService.summarizeText().

The summary is displayed in a Card.

import 'package:flutter/material.dart';

class SummarizerPage extends StatefulWidget {
  const SummarizerPage({super.key});

  @override
  State<SummarizerPage> createState() => _SummarizerPageState();
}

class _SummarizerPageState extends State<SummarizerPage> {
  final _controller = TextEditingController();
  String _summary = "";
  bool _loading = false;

  final service = ClaudeService("YOUR_API_KEY");

  void _summarize() async {
    setState(() => _loading = true);
    try {
      final result = await service.summarizeText(_controller.text);
      setState(() => _summary = result);
    } catch (e) {
      setState(() => _summary = "Error: $e");
    }
    setState(() => _loading = false);
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: const Text("AI Summarizer")),
      body: Padding(
        padding: const EdgeInsets.all(16),
        child: Column(
          children: [
            TextField(
              controller: _controller,
              maxLines: 5,
              decoration: const InputDecoration(
                hintText: "Paste text here...",
                border: OutlineInputBorder(),
              ),
            ),
            const SizedBox(height: 12),
            ElevatedButton(
              onPressed: _loading ? null : _summarize,
              child: _loading
                  ? const CircularProgressIndicator()
                  : const Text("Summarize"),
            ),
            const SizedBox(height: 20),
            if (_summary.isNotEmpty)
              Card(
                child: Padding(
                  padding: const EdgeInsets.all(16),
                  child: Text(_summary),
                ),
              ),
          ],
        ),
      ),
    );
  }
}

Advantages of Claude

• Safety by design: Claude is trained with “constitutional AI,” reducing harmful or biased outputs.

• Large context: With up to 200K tokens, it can handle very long documents.

• High-quality summaries: Excellent for research, study, or productivity apps.

Conclusion

Integrating AI into apps is no longer optional — it’s becoming a competitive edge. By combining Flutter’s cross-platform power with Claude’s intelligence, developers can create mobile apps that summarize, explain, or reason about content instantly.

This approach shifts the workload: instead of building custom AI pipelines, developers can focus on delivering better user experiences, while Claude provides the intelligence layer.

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Artificial Intelligence (AI) is transforming how we interact with technology