Additional documentation can be found at the Marlin Home Page. Please test this firmware and let us know if it misbehaves in any way. Volunteers are standing by!

Not for production use. Use with caution!

Marlin 2.1 takes this popular RepRap firmware to the next level by adding support for much faster 32-bit and ARM-based boards while improving support for 8-bit AVR boards. Read about Marlin's decision to use a "Hardware Abstraction Layer" below.

This branch is for patches to the latest 2.1.x release version. Periodically this branch will form the basis for the next minor 2.1.x release.

Download earlier versions of Marlin on the Releases page.

Before you can build Marlin for your machine you'll need a configuration for your specific hardware. Upon request, your vendor will be happy to provide you with the complete source code and configurations for your machine, but you'll need to get updated configuration files if you want to install a newer version of Marlin. Fortunately, Marlin users have contributed dozens of tested configurations to get you started. Visit the MarlinFirmware/Configurations repository to find the right configuration for your hardware.

To build and upload Marlin you will use one of these tools:

• The free Visual Studio Code using the Auto Build Marlin extension.
• The free Arduino IDE : See Building Marlin with Arduino
• You can also use VSCode with devcontainer : See Installing Marlin (VSCode devcontainer).

Marlin is optimized to build with the PlatformIO IDE extension for Visual Studio Code. You can still build Marlin with Arduino IDE, and we hope to improve the Arduino build experience, but at this time PlatformIO is the better choice.

We intend to continue supporting 8-bit AVR boards in perpetuity, maintaining a single codebase that can apply to all machines. We want casual hobbyists and tinkerers and owners of older machines to benefit from the community's innovations just as much as those with fancier machines. Plus, those old AVR-based machines are often the best for your testing and feedback!

Marlin includes an abstraction layer to provide a common API for all the platforms it targets. This allows Marlin code to address the details of motion and user interface tasks at the lowest and highest levels with no system overhead, tying all events directly to the hardware clock.

Every new HAL opens up a world of hardware. At this time we need HALs for RP2040 and the Duet3D family of boards. A HAL that wraps an RTOS is an interesting concept that could be explored. Did you know that Marlin includes a Simulator that can run on Windows, macOS, and Linux? Join the Discord to help move these sub-projects forward!

The Issue Queue is reserved for Bug Reports and Feature Requests. Please use the following resources for help with configuration and troubleshooting:

• Marlin Documentation - Official Marlin documentation
• Marlin Discord - Discuss issues with Marlin users and developers
• Facebook Group "Marlin Firmware"
• RepRap.org Marlin Forum
• Facebook Group "Marlin Firmware for 3D Printers"
• Marlin Configuration on YouTube

You can contribute patches by submitting a Pull Request to the (bugfix-2.1.x) branch.

• We use branches named with a "bugfix" or "dev" prefix to fix bugs and integrate new features.
• Follow the Coding Standards to gain points with the maintainers.
• Please submit Feature Requests and Bug Reports to the Issue Queue. See above for user support.
• Whenever you add new features, be sure to add one or more build tests to buildroot/tests. Any tests added to a PR will be run within that PR on GitHub servers as soon as they are pushed. To minimize iteration be sure to run your new tests locally, if possible.
  • Local build tests:
    • All: make tests-config-all-local
    • Single: make tests-config-single-local TEST_TARGET=...
  • Local build tests in Docker:
    • All: make tests-config-all-local-docker
    • Single: make tests-config-all-local-docker TEST_TARGET=...
  • To run all unit test suites:
    • Using PIO: platformio run -t test-marlin
    • Using Make: make unit-test-all-local
    • Using Docker make: maker unit-test-all-local-docker
  • To run a single unit test suite:
    • Using PIO: platformio run -t marlin_<test-suite-name>
    • Using make: make unit-test-single-local TEST_TARGET=<test-suite-name>
    • Using Docker make: maker unit-test-single-local-docker TEST_TARGET=<test-suite-name>
• If your feature can be unit tested, add one or more unit tests. For more information see our documentation on Unit Tests.

Marlin is constantly improving thanks to a huge number of contributors from all over the world bringing their specialties and talents. Huge thanks are due to all the contributors who regularly patch up bugs, help direct traffic, and basically keep Marlin from falling apart. Marlin's continued existence would not be possible without them.

Marlin is published under the GPL license because we believe in open development. The GPL comes with both rights and obligations. Whether you use Marlin firmware as the driver for your open or closed-source product, you must keep Marlin open, and you must provide your compatible Marlin source code to end users upon request. The most straightforward way to comply with the Marlin license is to make a fork of Marlin on Github, perform your modifications, and direct users to your modified fork.