API Charset and Encoding Fix Guide

When working with API calls in FlutterFlow, you might encounter issues where the response returns with strange characters, incorrect formatting, or unreadable content. These problems are often caused by improper charset or encoding settings either in the API request or the server response.

This guide shows you how to resolve such issues and ensure your API outputs are correctly displayed in your FlutterFlow project.

Follow the steps below:

1. Set Proper Request Headers

   Make sure your API call includes the appropriate headers to instruct the server on how to format the response. Add the following headers to your API configuration:

   • Content-Type: application/json

   • Charset: utf-8​

   These headers tell the server to return the data in JSON format using UTF-8 encoding, which is compatible with FlutterFlow.

   

2. Enable UTF-8 Decoding in FlutterFlow

   If the server does not specify encoding—or if you're still getting corrupted text—you can configure FlutterFlow to decode the API response as UTF-8 manually.

   To do this:

   1. Go to your API call setup in FlutterFlow.
   2. Scroll to Advanced Settings.
   3. Enable Force response decoding as UTF-8.

   This setting helps FlutterFlow correctly interpret the API response, especially from servers that don’t return standard headers.

   

Final Tips

• Always test your API calls in FlutterFlow’s API Test tab to ensure the response is properly formatted.
• Confirm that the external API supports UTF-8 and returns a valid JSON response.
• Review your server settings if you control the backend, to ensure it sends the correct headers.

note

Incorrect API call outputs due to charset or encoding can be quickly resolved by:

• Adding proper headers like Content-Type: application/json and Charset: utf-8.
• Enabling Force response decoding as UTF-8 in FlutterFlow’s API advanced settings. These simple steps will help you get accurate and readable data from your APIs, resulting in a smoother app development experience.

If you still face challenges, don't hesitate to reach out to our support team through Live chat or by emailing support@flutterflow.io