Sheets CMS — Flutter + Google Sheets as a Backend

A Flutter app that uses Google Sheets as a free CMS/database for a product catalog. Create, read, update, and delete products directly from a spreadsheet — no backend server required.

Built as a tutorial project to demonstrate real-world patterns: service account auth, the repository pattern, Riverpod state management, and graceful error handling.

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Features

• Product catalog — list products fetched from a Google Sheet
• Add / Edit / Delete — full CRUD with batch delete support
• Offline detection — pre-flight connectivity check before every request
• Retry with backoff — automatic exponential backoff (1 s → 2 s → 4 s) on transient failures
• Skeleton loading — shimmer-style placeholder cards while data loads
• Typed error handling — sealed Result<T> type, no raw exceptions leaking into the UI

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Tech Stack

Layer	Package
State management	flutter_riverpod + riverpod_annotation
Google Sheets API	googleapis + googleapis_auth
Connectivity	connectivity_plus
HTTP client	dio

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Spreadsheet Structure

Create a Google Sheet with the following columns starting at row 2 (row 1 = headers):

A — ID	B — Name	C — Price	D — Category	E — Description
1	Blue T-Shirt	29.99	Apparel	Soft cotton tee

Supported categories: Apparel, Accessories, Electronics, Other

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Setup

1. Google Cloud — Service Account

1. Go to Google Cloud Console and create a project.
2. Enable the Google Sheets API.
3. Create a Service Account and download its JSON key file.
4. Share your spreadsheet with the service account's email address (Editor access).

2. Add credentials to the project

Place the downloaded JSON key file at:

assets/service_account.json

Never commit this file. Add it to .gitignore.

3. Set your Spreadsheet ID

Open lib/features/catalog/data/sheets_repository.dart and replace the placeholder:

const _spreadsheetId = 'YOUR_SPREADSHEET_ID_HERE';

The ID is the long string in your sheet's URL: https://docs.google.com/spreadsheets/d/<spreadsheet-id>/edit

4. Run

flutter pub get
flutter run

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Project Structure

lib/
├── core/
│   ├── auth/               # Service account authentication
│   ├── connectivity/       # Offline detection
│   ├── result.dart         # Sealed Result<T> / SheetsError types
│   └── retry.dart          # Exponential backoff helper
└── features/
    └── catalog/
        ├── data/           # SheetsRepository — all API calls
        ├── domain/         # Product model
        └── presentation/   # CatalogScreen, AddProductScreen, EditProductScreen

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Resources

• Flutter documentation
• Riverpod Tutorial
• Google Sheets API reference
• googleapis Dart package