Arduino Libraries

To include a library, go to the code editor and type # on an empty line. You'll see a autocomplete dropdown with #include suggestions for popular libraries.

By default, Wokwi compiles your code with the standard built-in Arduino libraries, such as Wire.h and SPI.h.

Adding third party libraries

To add third-party libraries to your project, go to the "Library Manager" tab in the code editor, and press the blue "+" button. Type some text in the search box to search for a library (e.g. "FastLED"), and then click on one of the library names in the list to add it.

You can use this method to install any Arduino library from the Arduino Library Manager.

Uploading custom libraries

Paying users can upload any Arduino library by selecting a folder from their computer. To upload a custom library, click on the blue "+" button in the Arduino library manager and then click on "Upload a Library".

The selected folder should contain the source code for the library (.h and .c/.cpp files). After selecting a folder, Wokwi will zip its contents and upload it to the Wokwi build server. You will be able to see the library in the Library Mananger as a .zip file.

Anyone who opens the project will be able to download the library from the Library manager. Any user who creates a copy of the project will be able to use the library in the copied project.

The libraries.txt file

When you add libraries through the built-in "Library Manager", it will create a "libraries.txt" file in your project. It is a simple text file that lists all of libraries installed in your project, one library per line. Lines that start with "#" are comments.

Normally, you don't need to edit this file yourself - the "Library Manager" does this for you. But you can find this file useful if you want to install a specific version of a library. To select a specific version, add "@" after the library name, followed by the version that you want to install.

For example, the following file will install the latest versions of Servo and FastLED, as well as version 2.3.0 of MySensors:

# Sample libraries.txt file:
Servo
FastLED

# Install a specific version of a library:
[email protected]

Custom libraries have the following format: the library name, followed by a the text "@wokwi:", and a unique identifier of the library's zip file on Wokwi's servers. You can copy custom libraries to a different project by copying the relevant lines from libraries.txt into the other project.