Creating a custom app > Working with plug-ins > Creating custom plug-ins

Creating custom plug-ins

If you are a C or C++ programmer and familiar with calculations and scripts in FileMaker Pro Advanced, you can create FileMaker plug-ins. The plug-ins can take advantage of recursion and looping, or hook into other programming interfaces. To create a custom plug-in, you will need the FileMaker plug-in SDK.

To use plug-ins, FileMaker Pro Advanced users need to allow solution files to install and enable plug-ins. For hosted files, the server administrator needs to allow the Install Plug-In File script step to update plug-ins installed on the server in Admin Console for FileMaker Server or FileMaker Cloud for AWS.

To prepare your custom plug-ins:

1. Using C or C++, create a plug-in file.

Windows: The plug-in extension must be .fmx (32-bit FileMaker Pro Advanced) or .fmx64 (64-bit FileMaker Pro Advanced).

macOS: The plug-in extension must be .fmplugin.

2. Compile and test the plug-in.

Though digitally signing your plug-in is optional, users will be asked whether to permit an unsigned plug-in to load. See Setting permitted hosts and plug-ins preferences.

3. Install the compiled plug-in file in a container field in your FileMaker solution. See Installing plug-ins.

4. (optional) Set up the solution file to check the version of installed plug-ins and update them if needed. See Plug-in update example.

To make plug-ins available in a file, users need to:

1. Enable and configure plug-ins in the Preferences dialog box in FileMaker Pro Advanced. See Setting plug-in preferences.

2. (optional) Select Allow Solutions to Install Files in the plug-in preferences to have plug-in updates installed automatically. See Plug-in update example.

3. Do one of the following:

To use a function provided by the plug-in, sort the list of functions in the Specify Calculation dialog box by type. Under the name of the plug-in, choose a function.

To use a script step provided by the plug-in, sort the list of script steps in the Script Workspace by category. Under the name of the plug-in, choose a script step.


For security reasons, system administrators might require users to disable Allow Solutions to Install Files. Contact the system administrator at your customer site for more information.

Related topics 

Get(InstalledFMPlugins) function