DOIs are unique and persistent identifiers, and their pattern contains three parts:
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
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Each DOI must be unique
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Only use approved characters: DOI suffixes can be any alphanumeric string that includes combinations the following approved characters:
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Letters of the Roman alphabet, A-Z (see below on case insensitivity)
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Numbers, 0-9
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-._;()/ (hyphen, period, underscore, semicolon, parentheses, forward slash). Note that the non-breaking hyphen (U+2011), figure dash (U+2012), en dash (U+2013), and em dash (U+2014) are not approved characters. The only approved hyphen is the hyphen-minus (U+002D).
- Note, some older (pre-2008) DOIs which contain other characters. Learn more about suffixes containing special characters.
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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/