{"id":219,"date":"2009-03-03T12:55:51","date_gmt":"2009-03-03T11:55:51","guid":{"rendered":"http:\/\/www.ewerkzeug.info\/?p=219"},"modified":"2025-12-01T10:18:22","modified_gmt":"2025-12-01T09:18:22","slug":"allowed-characters-in-email-addresses-or-mailbox-names","status":"publish","type":"post","link":"https:\/\/www.ewerkzeug.info\/en\/erlaubte-zeichen-in-email-adressen-bzw-mailboxnamen\/","title":{"rendered":"Valid characters in email addresses or mailbox names"},"content":{"rendered":"<p>Read here which special characters can be used in email addresses.&nbsp;<\/p>\n\n\n<h2 class=\"simpletoc-title\">Table of Contents<\/h2>\n<ul class=\"simpletoc-list\">\n<li><a href=\"#die-syntax\">The syntax<\/a>\n\n\n<ul><li>\n<a href=\"#local-part\">local part<\/a>\n\n<\/li>\n<li><a href=\"#domain-part\">domain part<\/a>\n\n<\/li>\n<\/ul>\n<li><a href=\"#existiert-die-emailadresse\">Does the e-mail address exist?<\/a>\n\n<\/li>\n<li><a href=\"#emailversand-absichern\">Secure email delivery<\/a>\n<\/li><\/ul>\n\n\n<h2 id=\"die-syntax\" class=\"wp-block-heading\">The syntax<\/h2>\n\n\n\n<figure class=\"wp-block-image aligncenter\"><img loading=\"lazy\" decoding=\"async\" width=\"909\" height=\"147\" src=\"https:\/\/www.ewerkzeug.info\/wp-content\/uploads\/mailadresse.png\" alt=\"Composition of an e-mail address\" class=\"wp-image-3154\" srcset=\"https:\/\/www.ewerkzeug.info\/wp-content\/uploads\/mailadresse.png 909w, https:\/\/www.ewerkzeug.info\/wp-content\/uploads\/mailadresse-300x49.png 300w, https:\/\/www.ewerkzeug.info\/wp-content\/uploads\/mailadresse-768x124.png 768w\" sizes=\"auto, (max-width: 909px) 100vw, 909px\" \/><figcaption class=\"wp-element-caption\">Composition of an e-mail address<\/figcaption><\/figure>\n\n\n\n<h3 id=\"local-part\" class=\"wp-block-heading\">local part<\/h3>\n\n\n\n<p>These characters are part of an email address <strong>before<\/strong> the @ sign (i.e. <strong>left from @<\/strong>which is the local part):<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Letters<\/strong> A-Z and a-z (without accents and no umlauts, no \u00df)<\/li>\n\n\n\n<li><strong>Digits<\/strong> 0-9 <\/li>\n\n\n\n<li>The following <strong>Special characters<\/strong>: <code>! # $ % &amp; ' * + - \/ = ? ^ _ ` . { | } ~<\/code><\/li>\n<\/ul>\n\n\n\n<p>The following combination of characters is actually a valid email address in terms of syntax:<\/p>\n\n\n\n<pre class=\"wp-block-code\" style=\"font-size:clamp(24.034px, 1.502rem + ((1vw - 3.2px) * 1.247), 40px);\"><code>!#$%&amp;'*+-\/=?^_`.{|}~<em>@example.com<\/em><\/code><\/pre>\n\n\n\n<p>Or this email address is also valid:<\/p>\n\n\n\n<pre class=\"wp-block-code\" style=\"font-size:clamp(24.034px, 1.502rem + ((1vw - 3.2px) * 1.247), 40px);\"><code>-'-\/-{<em>@example.com<\/em><\/code><\/pre>\n\n\n\n<p>(Source:<a href=\"http:\/\/en.wikipedia.org\/wiki\/Email_address\" target=\"_blank\" rel=\"noopener noreferrer\"> Wikipedia<\/a>)<\/p>\n\n\n\n<p>The previous applies if the local part is NOT surrounded by quotation marks. In principle, however, the local part can also be enclosed in quotation marks, and then further characters are possible in the local part.<\/p>\n\n\n\n<p>The following e-mail addresses may therefore also be valid:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><code>\".John.Doe\"@example.com<\/code><\/li>\n\n\n\n<li><code>\"John.Doe.\"@example.com<\/code><\/li>\n\n\n\n<li><code>\"John..Doe\"@example.com<\/code><\/li>\n\n\n\n<li><code>\"John Doe\"@example.com<\/code><\/li>\n\n\n\n<li><code>\" \"@example.org<\/code>&nbsp;(space between the quotation marks)<\/li>\n\n\n\n<li><code>\"john..doe\"@example.org<\/code>&nbsp;(points strung together)<\/li>\n\n\n\n<li><code>\"very.(),:;[]\\\".VERY.\\\"very@\\\\ \\\"very\\\".unusual\"@strange.example.com<\/code><\/li>\n<\/ul>\n\n\n\n<p>However, it is not recommended to allow such mail addresses on the mail server (<a rel=\"noreferrer noopener\" href=\"https:\/\/www.rfc-editor.org\/rfc\/rfc5321\" target=\"_blank\">https:\/\/www.rfc-editor.org\/rfc\/rfc5321<\/a>page 41). Thanks to the <a href=\"https:\/\/www.ewerkzeug.info\/en\/allowed-characters-in-email-addresses-or-mailbox-names\/#comment-119210\">Commentator Maddse<\/a> for the hint.<\/p>\n\n\n\n<ins class=\"adsbygoogle\"\n     style=\"display:block; text-align:center;\"\n     data-ad-layout=\"in-article\"\n     data-ad-format=\"fluid\"\n     data-ad-client=\"ca-pub-2233617471649092\"\n     data-ad-slot=\"3695473590\"><\/ins>\n<script>\n     (adsbygoogle = window.adsbygoogle || []).push({});\n<\/script>\n\n\n\n<p>But now to the restrictions.<\/p>\n\n\n\n<p>Please note that various special characters only appear in the <strong>before the @<\/strong> the e-mail address (the <strong>local-part<\/strong>) are generally permitted. However, you may not necessarily be able to use all of these characters in the mailbox name on your own mail server. Which of the characters you can actually use for your mail address also depends on the configuration of the mail servers by the responsible administrators or the software used for this purpose.<\/p>\n\n\n\n<h3 id=\"domain-part\" class=\"wp-block-heading\">domain part<\/h3>\n\n\n\n<p>For the domain (the part <strong>behind the @<\/strong>) other rules apply. Permitted characters in <strong>Domain names<\/strong> are:\u00a0<strong>\u201ea-z\u201c, \u201e0-9\u201c and \u201e-\u201e<\/strong> (hyphen). The dot \u201c . \u201c of course, because the domain name cannot be valid without it. The minimum length of the domain name is 3 characters, the maximum length is 63 characters. The name may not begin or end with a hyphen. A valid domain name consists of a maximum of 63 characters. If you insist, you can also use \u00e4,\u00f6, or \u00fc in the domain part, but I advise against this.<\/p>\n\n\n\n<hr class=\"wp-block-separator has-css-opacity\"\/>\n\n\n\n<h2 id=\"existiert-die-emailadresse\" class=\"wp-block-heading\">Does the e-mail address exist?<\/h2>\n\n\n\n<p>You can use the following online tools to check whether an email address is syntactically correct and whether it exists at all. <\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><a href=\"https:\/\/www.experte.de\/email-pruefen\" target=\"_blank\" rel=\"noreferrer noopener\">https:\/\/www.experte.de\/email-pruefen<\/a><\/li>\n\n\n\n<li><a rel=\"noreferrer noopener\" href=\"https:\/\/captainverify.com\/de\/mail-tester.html\" target=\"_blank\">https:\/\/captainverify.com\/de\/mail-tester.html<\/a><\/li>\n\n\n\n<li><a rel=\"noreferrer noopener\" href=\"http:\/\/www.emailtester.de\/tools\/mailtester-emailadressen-checker.php\" target=\"_blank\">http:\/\/www.emailtester.de\/tools\/mailtester-emailadressen-checker.php<\/a><\/li>\n<\/ul>\n\n\n\n<h2 id=\"emailversand-absichern\" class=\"wp-block-heading\">Secure email delivery<\/h2>\n\n\n\n<p>If you want to know how you can largely prevent someone from using your email address as the sender of spam emails, read this article about <a rel=\"noreferrer noopener\" href=\"https:\/\/www.ewerkstatt.com\/2021\/07\/05\/spf-dkim-und-dmarc-was-ist-das\/\" target=\"_blank\">SPF, DKIM and DMARC<\/a>. <\/p>","protected":false},"excerpt":{"rendered":"<p>You can use these special characters in email addresses. Plus: Online test tools<\/p>","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_seopress_robots_primary_cat":"none","_seopress_titles_title":"G\u00fcltige Zeichen in Email-Adressen bzw. Mailboxnamen","_seopress_titles_desc":"Welche Zeichen sind bei E-Mail-Adressen erlaubt? Plus: Pr\u00fcfung einer E-Mail Adresse hinsichtlich g\u00fcltiger Zeichen mit einem einfachen PHP-Code.","_seopress_robots_index":"","iawp_total_views":17739,"footnotes":""},"categories":[29],"tags":[],"class_list":["post-219","post","type-post","status-publish","format-standard","hentry","category-tipps"],"blocksy_meta":{"styles_descriptor":{"styles":{"desktop":"","tablet":"","mobile":""},"google_fonts":[],"version":6}},"_links":{"self":[{"href":"https:\/\/www.ewerkzeug.info\/en\/wp-json\/wp\/v2\/posts\/219","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.ewerkzeug.info\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.ewerkzeug.info\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.ewerkzeug.info\/en\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.ewerkzeug.info\/en\/wp-json\/wp\/v2\/comments?post=219"}],"version-history":[{"count":6,"href":"https:\/\/www.ewerkzeug.info\/en\/wp-json\/wp\/v2\/posts\/219\/revisions"}],"predecessor-version":[{"id":5745,"href":"https:\/\/www.ewerkzeug.info\/en\/wp-json\/wp\/v2\/posts\/219\/revisions\/5745"}],"wp:attachment":[{"href":"https:\/\/www.ewerkzeug.info\/en\/wp-json\/wp\/v2\/media?parent=219"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.ewerkzeug.info\/en\/wp-json\/wp\/v2\/categories?post=219"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.ewerkzeug.info\/en\/wp-json\/wp\/v2\/tags?post=219"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}