How do I fix: Using the correct data type?

Step 1: Use the `jsonDecode` function to parse the JSON response into a Map or List, depending on what is returned by the server.Step 2: Check the documentation for the http package and the server you are interacting with to ensure that you are using the correct data types and accessing them correct

Coding⏱️ 3 min read📅 2026-06-04

How to Fix: Unhandled Exception: InternalLinkedHashMap<String, dynamic>' is not a subtype of type 'List<dynamic>

Q: Step-by-Step Verified Fixes Accessing a Map as a List?

Step 1: Use the `map.values` property to access all values in the Map, rather than trying to access an element by index.Step 2: If you need to access a specific value from the Map, use the `map.keys` or `map.entries` properties to get an iterable of keys or entries.Step 3: Make sure that the server

The error occurs because the response body is not a list, but an internal linked hash map. You need to access the data using its key-value pairs.

Quick Answer: Use json.decode() method to parse the JSON string into a dynamic object, and then access the data using its key-value pairs.

📋 Table of Contents

💡 Why You Are Getting This Error
🛠️ Step-by-Step Verified Fixes
🎯 Final Words

The error message 'Unhandled Exception: type '_InternalLinkedHashMap<String, dynamic>' is not a subtype of type 'List' indicates that there is an issue with how you are trying to access or manipulate data in your code. This error specifically occurs when you try to use a data structure that is not compatible with the operations you are attempting to perform on it.

This error affects developers who are using Dart and the http package to fetch JSON data from a server. The error can occur when the server returns a JSON response that contains a dynamic map, but the code is expecting a list of items.

💡 Why You Are Getting This Error

The primary cause of this error is likely due to the fact that you are trying to access an element in a List using the index of a Map. In Dart, Maps and Lists are two different data types with different properties and behaviors.
Another possible cause could be that the server returns a JSON response that contains a dynamic map instead of a list.

🛠️ Step-by-Step Verified Fixes

Accessing a Map as a List

Step 1: Use the `map.values` property to access all values in the Map, rather than trying to access an element by index.
Step 2: If you need to access a specific value from the Map, use the `map.keys` or `map.entries` properties to get an iterable of keys or entries.
Step 3: Make sure that the server returns a JSON response that contains a list of items, and not a dynamic map.

Using the correct data type

Step 1: Use the `jsonDecode` function to parse the JSON response into a Map or List, depending on what is returned by the server.
Step 2: Check the documentation for the http package and the server you are interacting with to ensure that you are using the correct data types and accessing them correctly.

🎯 Final Words

To resolve this error, you need to understand how Maps and Lists work in Dart and use the correct data type when accessing or manipulating data. Make sure to check the documentation for the http package and the server you are interacting with to ensure that you are using the correct data types and accessing them correctly.

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