React Native with TypeScript

Using:

• React Native
• Expo for easier setup
• TypeScript
• Supabase or Firebase
• AI API through your backend

This is probably the best balance of:

• easy to start
• good for iPhone + Android
• strong community
• JavaScript/TypeScript everywhere
• easier than native Swift/Kotlin for one-person or small-team development

Best language for a mobile version

TypeScript

Why:

• works great with React Native
• lets you build cross-platform apps
• easier than building separate iOS and Android apps
• lots of libraries for forms, notifications, auth, API calls
• safer and cleaner than plain JavaScript

Best stack for your mobile app

Frontend mobile app

• React Native
• Expo

Backend

Choose one:

• Supabase if you want database + auth + backend features
• or Firebase if you want quick setup and notifications
• or custom Node.js/TypeScript backend if you want more control

AI

• call an AI API from your backend
• use it to parse natural language tasks and generate reminder suggestions

Notifications

• Expo Notifications for push notifications
• later maybe Firebase Cloud Messaging for more advanced push support

Why Expo is a great starting point

Expo makes React Native much easier because it handles a lot for you:

• project setup
• running on your phone
• notifications
• device APIs
• testing quickly with Expo Go

This is ideal if you’re just starting.

Recommended app plan

Version 1 mobile MVP

Build these features first:

Core task features

• add task
• edit task
• mark complete
• delete task

Reminder features

• set date/time reminder
• local push notification
• simple repeat reminders if possible later

AI feature

• user types: “Remind me to call mom tomorrow at 6”
• AI returns structured data:
  • title
  • due date
  • reminder time

That is already a strong MVP.

Best way to get started coding

Step 1: Create the app

With Expo:

bashnpx create-expo-app todo-ai-mobile cd todo-ai-mobile npm install npm run start

If you want TypeScript, choose the TypeScript template or rename files as needed.

Step 2: Build basic screens

You’ll probably want these screens:

• Home / Task List
• Add Task
• Task Details
• Settings

Step 3: Define your task model

Example:

tsexport type Task = {  id: string;  title: string;  notes?: string;  completed: boolean;  dueDate?: string;  reminderAt?: string;  priority?: "low" | "medium" | "high";  createdAt: string; };

Step 4: Start with local storage first

Before setting up a backend, store tasks on the device using:

• AsyncStorage

This is much easier for early development.

Later move to:

• Supabase
• Firebase
• or your own backend

Suggested mobile app structure

bashtodo-ai-mobile/ ├── app/
│   ├── index.tsx
│   ├── add-task.tsx
│ ├── task/[id].tsx │   └── settings.tsx
├── components/
│   ├── TaskItem.tsx
│   ├── TaskForm.tsx
│   └── ReminderPicker.tsx
├── types/
│   └── task.ts
├── lib/
│   ├── storage.ts
│   ├── notifications.ts
│   └── ai.ts
└── hooks/

If you use Expo Router, this structure works nicely.

How reminders should work at first

For version 1, use local notifications.

That means:

• when user creates a reminder
• app schedules a notification on the device

This is easier than building a full server-based notification system.

Use:

• expo-notifications

This is a very good first step.

How AI should work

Important: don’t call AI directly from the app with a secret API key.

Instead:

1. mobile app sends user text to your backend
2. backend calls AI model
3. backend returns parsed task JSON
4. app shows result and user confirms

Example input:

“Remind me to buy groceries tomorrow at 5 pm”

Example output:

json{ "title": "Buy groceries", "dueDate": "2026-04-15", "reminderAt": "2026-04-15T17:00:00", "priority": "medium" }

What backend should you use?

For a mobile MVP, I’d recommend one of these:

Option A: Simplest practical setup

Supabase + small serverless AI endpoint

Use Supabase for:

• auth
• database
• user data

Use a small backend route for:

• AI task parsing
• secure API calls

Option B: Firebase

Good if you want:

• easy mobile integration
• notifications
• auth
• real-time sync

Option C: Full custom backend

Use Node.js/Express if you want full control, but this is more work.

My actual recommendation

For your app idea:

Easiest strong setup:

• React Native
• Expo
• TypeScript
• AsyncStorage first
• expo-notifications
• Supabase later
• small Node/Next backend for AI

This lets you:

• build the mobile UI quickly
• test reminders on a real phone
• add AI without too much complexity

What not to do first

Avoid starting with:

• separate iOS and Android apps
• complex push notification servers
• recurring scheduling logic
• too many AI features
• full calendar syncing

Start simple:

1. create task
2. save task
3. set reminder
4. parse text with AI

Development roadmap

Phase 1

• Expo app
• task list UI
• add task form
• local storage

Phase 2

• reminder picker
• local notifications

Phase 3

• backend endpoint for AI parsing
• “smart add task” input

Phase 4

• cloud sync with Supabase/Firebase
• auth
• smarter reminder suggestions

If you are choosing between React Native and Flutter

Pick React Native if:

• you want to use JavaScript/TypeScript
• you may build a web version later
• you want easier AI/backend integration with JS ecosystem

Pick Flutter if:

• you like Dart
• you care a lot about custom UI polish
• you’re okay learning a less common language

For your specific app, I would still choose React Native + TypeScript.

My final answer

For a mobile AI to-do reminder app, the best place to start is:

React Native + Expo + TypeScript

And build this in order:

1. simple to-do list
2. local reminders
3. AI task parsing
4. cloud sync