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Knowledge base Troubleshooting page encoding issues

Troubleshooting page encoding issues

Update 08/04/2026

This guide is intended for developers and webmasters who are experiencing issues with the display of special characters (e.g., accents, Arabic characters, Chinese characters, emojis, etc.) on an Infomaniak website or in its database.

Introduction

Common causes of incorrectly displayed characters that appear instead of special characters or emojis like ??:
- PHP connection in utf8 instead of utf8mb4
- MySQL table or column in latin1 or utf8 instead of utf8mb4
- SQL file encoded differently from the import setting
- Incorrectly encoded HTML/CSS/JS files
- Missing or incorrect charset declaration on the HTML, PHP, or HTTP side
Common solutions:
- Use utf8mb4 everywhere: database, connections, tables, columns, files, headers
- Validate the encoding of all files and dumps
- Test the display of emojis, accents, and other multilingual characters
Also, refer to this other guide to force a different encoding when connecting to a MySQL database.

Use a text editor that supports saving in UTF-8 without BOM (Visual Studio Code, Sublime Text, Notepad++...)

1. Use UTF-8 or UTF-8MB4 everywhere

MySQL's utf8 encoding does not support 4-byte characters, such as emojis. These will be displayed as ??. Therefore, you should use utf8mb4, which is a true, complete implementation of UTF-8.

2. HTML – Correct encoding declaration

In the <head> of your HTML pages:

Also, make sure that the CSS/JS files are saved in UTF-8 (without BOM).

Assurez-vous aussi que les fichiers CSS/JS sont enregistrés en UTF-8 (sans BOM).

3. PHP – Enforce UTF-8 or UTF-8MB4

a) HTTP Headers

header('Content-Type: text/html; charset=utf-8');

b) MySQL connection (MySQL API)

b) Connexion MySQL (API MySQL)

$connection = mysql_connect($host, $user, $pass);
mysql_set_charset('utf8mb4', $connection);

c) PDO Connection

 $dsn = "mysql:host=localhost;dbname=ma_base;charset=utf8mb4";
$pdo = new PDO($dsn, $user, $pass, [
    PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION
]);

4. MySQL database

a) Configuration in phpMyAdmin

The database, tables, and columns must be in utf8mb4_unicode_ci or utf8mb4_general_ci.
In the Operations tab, choose utf8mb4_unicode_ci for the collation.

b) Useful SQL commands

ALTER DATABASE ma_base CHARACTER SET = utf8mb4 COLLATE = utf8mb4_unicode_ci;
ALTER TABLE ma_table CONVERT TO CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci;

c) After the PHP connection

mysqli_query($conn, "SET NAMES 'utf8mb4'");
mysqli_query($conn, "SET CHARACTER SET 'utf8mb4'");

5. .user.ini / .htaccess file

To force server-side encoding (Apache):

AddDefaultCharset utf-8
Header set Content-Type "text/html; charset=utf-8"
# For PHP
php_value default_charset UTF-8
php_value mbstring.internal_encoding UTF-8

6. Import/export SQL dumps

Errors such as é becoming ? or an emoji ☺ becoming ?? often stem from an encoding mismatch.

Check the encoding of the SQL file before importing. Use iconv if necessary:

iconv -f ISO-8859-1 -t UTF-8 dump.sql > dump_utf8.sql

In phpMyAdmin, specify the import encoding (e.g. UTF-8, UTF-8MB4 or latin1) according to the file.

Link to this FAQ: https://faq.infomaniak.com/1124

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