# Ticket of the month - November 2025 - Do not include special characters at the end of DOIs

**URL:** <https://community.crossref.org/t/ticket-of-the-month-november-2025-do-not-include-special-characters-at-the-end-of-dois/14916>\
**Category:** Content Registration\
**Tags:** content-registration, doi-suffix, constructing\_dois, ticket\_of\_month\
**Created:** [9 December 2025 11:16 UTC](https://community.crossref.org/t/ticket-of-the-month-november-2025-do-not-include-special-characters-at-the-end-of-dois/14916 "2025-12-09T11:16:30Z")\
**Posts on this page:** 1\
**Page:** 1

<div class="post-metadata">

**Author:** ![eatoni](https://avatars.discourse-cdn.com/v4/letter/e/d07c76/32.png) [@eatoni](https://community.crossref.org/u/eatoni)\
**Post date:** [9 December 2025 11:16 UTC](https://community.crossref.org/t/ticket-of-the-month-november-2025-do-not-include-special-characters-at-the-end-of-dois/14916/1 "2025-12-09T11:16:31Z")

</div>

DOIs are unique and persistent identifiers, and their pattern contains three parts:

 ![image](https://us1.discourse-cdn.com/flex020/uploads/crossref/original/2X/a/a37f4af5bdca38a945501b513be3df5685e5d364.png)

The DOI prefix is automatically assigned to you when you become a Crossref member. As a member, you are only required to create and manage your suffixes.

The key question is: **What special characters are actually allowed in a DOI suffix?** According to our rules, you can use the following special characters: **hyphen (-), period (.), underscore (\_), semicolon (;), parentheses (()), and forward slash (/)**. However, it is **not recommended** to end a DOI with a special character. If a human sees a DOI ending in a **period (.)**, they often delete it before trying to resolve it, which typically leads to an error page (‘DOI NOT FOUND’). Similarly, machines often fail to correctly resolve DOIs that end with a **forward slash (/)**. Therefore, we strongly recommend against including any of these characters at the end of your DOIs.

Lastly, let’s recap the rules to construct your DOI suffix

- Each DOI must be unique

- Only use approved characters: DOI suffixes can be any alphanumeric string that includes combinations the following approved characters:

- Suffixes are case insensitive, so 10.1006/abc is the same in the system as 10.1006/ABC. Note that using lowercase is better for accessibility.

Please refer to our documentation pages for a more detailed guide on how to construct your DOI here [https://www.crossref.org/documentation/member-setup/constructing-your-dois/](https://www.crossref.org/documentation/member-setup/constructing-your-dois/)