flutter_model_assert 0.0.3

Early runtime validator for backend JSON responses to prevent type crashes and detect API contract mismatches in Flutter.

FlutterModelAssert

A lightweight, runtime API contract validator for Flutter that prevents silent backend changes from crashing your app due to unexpected type or structure mismatches.

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❗ Problem it solves

Flutter apps rely on predefined Dart models to parse API responses.
When backend teams update an API field type (e.g., int → double, double → String, int → String, or rename/remove keys), Flutter throws errors like:

This causes:

• App crashes at runtime
• API parsing failures
• Broken UI or infinite loading states
• Time-consuming debugging to find the exact mismatched field

FlutterModelAssert detects these issues early and safely before parsing, giving clear error reports so developers can fix instantly.

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✨ Features

• Validates required keys in JSON responses
• Compares backend response types vs expected Dart model types
• Supports nested JSON validation
• Prevents runtime crashes by failing safely
• Provides exact field mismatch reports
• No code generation, no reflection (dart:mirrors) needed
• Ideal for QA, staging, and debug builds
• Works with http, Dio, or any JSON source

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🚀 Installation

Add to pubspec.yaml:

dependencies:
  flutter_model_assert: ^0.0.1
# flutter_model_assert