This guide details the allowed and prohibited characters when creating an email address (up to 64 characters) in an Infomaniak Mail Service.

Introduction

• The allowed characters differ depending on whether they appear before or after the at symbol @. For example, in nom-utilisateur.mail@nom-domaine.xyz:
  • Before the at symbol: the nom-utilisateur.mail part corresponds to the username.
  • After the at symbol: the nom-domaine.xyz part corresponds to the domain name.
• To learn about the possibilities offered at the domain name level (the part after the at symbol @), please refer to this other guide.

Part before the at symbol: username.mail

RFC 5321 (❓: help) and RFC 5322 (❓: help) define the general syntax of email addresses. However, email providers – including Infomaniak – apply additional restrictions to ensure security, consistency, and compatibility with most software/email clients.

For example, an address such as -@exemple.com is syntactically valid according to RFC 5322, but is not accepted when creating accounts on Infomaniak servers.

These additional rules allow, in particular:

• to prevent abuse (spam, malicious automation, etc.);
• to comply with naming conventions (an identifier consisting only of - is meaningless);
• to ensure compatibility with software and email clients that do not handle certain address formats correctly.

Allowed characters before the at symbol

The following characters can be used in the part of an Infomaniak email address that comes before the at symbol:

Are uppercase letters allowed?

Yes. From a technical and syntactical standpoint, uppercase letters (from A to Z) are accepted in the part located before the at symbol. However, they are strongly discouraged. Although tolerated during creation, most email servers (and web best practices) recommend using only lowercase letters. Using uppercase letters can lead to confusion, complicate input for your contacts, and cause distribution or connection errors in some strict software/email clients.

Characters not allowed before the at symbol

The following characters (at sign, exclamation mark, hash, dollar sign, percent sign, caret, ampersand, asterisk, parenthesis, equals sign, bracket, chevron, comma, quotation marks, semicolon, question mark…) cannot be used to create an Infomaniak email address: