HDK File

What are HDK files and how to open them

Are you having problems opening a HDK file or are you simply curious about its contents? We're here to explain the properties of these files and provide you with software that can open or handle your HDK files.

What is a HDK file?

A .HDK file is a HotDocs Registration Key file.

A HotDocs Registration Key File (extension .HDK) is a file issued by the HotDocs vendor to a licensed publisher under HotDocs software. It serves as a publisher key enabling the registration of document templates for use with the free HotDocs Player, allowing those templates to be published commercially and used outside of the HotDocs Developer environment.

HotDocs Developer generates templates - documents with variable fields and logic - that can be published for use by end users via HotDocs Player. When publishing templates with registration, the publisher places the .HDK file (often named Register.hdk) into the HotDocs installation folder. In the publishing wizard, one selects options such as "Register component files," supplying a password associated with the publisher key file. Once registered, the resulting template sets produced can operate with HotDocs Player.

HotDocs' official documentation lists the .HDK extension among its file types. The .HDK file is identified as "HotDocs Registration File (required when publishing templates for commercial use with HotDocs Player)."

How to open HDK files

We have identified one HDK opener that is compatible with this specific type of HDK file.

Programs that open HotDocs Registration Key files

Last updated: August 7, 2026

Various apps that use files with this extension

These apps are known to open certain types of HDK files. Remember, different programs may use HDK files for different purposes, so you may need to try out a few of them to be able to open your specific file.

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