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mbed Online Compiler

The online compiler enables you to either write your code from scratch or import an existing project and modify it to suit your needs. The only thing you need is an mbed developer account.

The compiler is always available on https://developer.mbed.org/compiler/.

Video summary

Video tutorial

Importing code to the compiler

There are two methods of importing the code into the online compiler: directly from a program presented on the site, or using the compiler’s Import button:

  1. Directly from the site: wherever you see a program on the site, you should see an Import button:

    Most code snippets on the site can be directly imported

    Clicking that button will take you to the compiler; you can then give the program a new name and import it to your workspace:

    Importing to the mbed Online Compiler

  2. The compiler’s Import button: click the Import button in the compiler to open the Import Wizard:

    Triggering the Import Wizard from within the mbed Online Compiler

    You can search for a program by name, or perform an empty search to show all available programs:

    The applications list

    Double click a program to import it.

Creating a new program

  1. From the New menu, select Program:

    The applications listTriggering a new program

  2. The Create new program pop-up opens.

    1. Select your platform (board).
    2. You can create from an existing template, or from an empty program.
    3. Enter a unique name.

    Creating a new program

  3. Create a main.cpp file in your program:

    1. Right click on the program and select New File…. The Create new file popup opens.

      Adding a file

    2. Enter main.cpp as the file name.

      Naming the new file

  4. Import the mbed OS library so you can build your program with the mbed OS code base:

    1. Click Import. The Import Wizard opens.
    2. Go to the Libraries tab and search for “mbed”, or perform an empty search to show all libraries:

      Searching for mbed OS

    3. Double click on “mbed” to import it. The library is added to your program.

      mbed OS is now in the workspace

Getting your program on your board

The mbed Online Compiler builds a file that can run on your board. All you need to do is:

  1. Select the correct board.
  2. Compile the code and download the compiled file.
  3. Copy the file to your board.

Selecting your board

mbed programs can be built to run on multiple boards. The hard work is done behind the scenes, by mbed OS itself. All you need to do is tell the mbed Online Compiler which board you’re building for.

To select a board as the build target:

  1. The compiler shows the current build board’s name on the upper right corner:

    Showing current board. Click the board to open the full list

  2. Click the name of the board you need:

    Click a board to set it as the compilation board

    If the board isn’t already on your list, go to the board’s page on mbed.com and click the Add to your mbed Compiler button:

    Adding a board to the mbed Online Compiler list

Compile and download

The Compile menu offers five options:

  1. Compile: builds your code and downloads a binary file. Current program only.
  2. Compile All: same as compile, but for all programs.
  3. Build Only: compiles your code but doesn’t download the result.
  4. Compile Macros: defines additional macros at compile time.
  5. Update Docs: see the guide for documenting APIs.

Copying the file to the board

Note: If you’re working on Windows, you might need to install a driver to allow you to copy to your board. Please see the Windows Serial Driver section.

Your board should appear on your computer as removable storage. To run your program on the board, simply drag and drop the file you downloaded in the previous section.

The device appears as removable storage, under the name MBED

Keyboard shortcuts

Shortcut Description
Hold Ctrl Interactive mode
Shift + Home Select from current position to beginning of line
Shift + End Select from current position to end of line
Ctrl + Home Go to beginning of file
Ctrl + End Go to end of file
Ctrl + Shift + Home Select from current position to beginning of file
Ctrl + Shift + End Select from current position to end of file
Shift + Page Up Select from current position up one page
Shift + Page Down Select from current position down one page
Shift + any arrow Extend or reduce text selection
Ctrl + left arrow Go to beginning of the previous word
Ctrl + right arrow Go to beginning of the next word
Ctrl + up arrow Scroll up one row
Ctrl + down arrow Scroll down one row

Ctrl key sequences

Shortcut Description
Ctrl + A Select all
Ctrl + B Compile only (no download prompt)
Ctrl + Shift + B Compile all and download
Ctrl + C Copy (only selected text)
Ctrl + Shift + C Commit
Ctrl + D Compile and download
Ctrl + Shift + D Duplicate line
Ctrl + E Erase current line
Ctrl + F Find and replace
Ctrl + Alt + F Find in files
Ctrl + Shift + F Format code (selected text or current file)
Ctrl + H Find and replace
Ctrl + K Find and replace
Ctrl + L Change selected text to lower case
Ctrl + R Current file’s revision history (must be in single file mode)
Ctrl + S Save current file
Ctrl + Alt + S Save as
Ctrl + Shift + S Save all
Ctrl + U Change select text to upper case
Ctrl + V Paste text from clipboard
Ctrl + W Close current file (doesn’t work on Chrome
Ctrl + Shift + W Close all (doesn’t work on Chrome
Ctrl + X Cut selected text
Ctrl + Y Redo
Ctrl + Z Undo
Ctrl + / Toggle line comment (using slashes)
Ctrl + Shift + / Toggle block comment (using //)


Shortcut Description
Tab Increase text indent
Shift + Tab Decrease text indent
Esc Close find or toggle editor area full screen
Ins Toggle insert mode
Ctrl + Ins Copy selected text
Shift + Ins Paste text from clipboard
Shift + Del Cut selected text
F8 Compile only (no download prompt
F9 Compile and download
F10 Compile all and download

Touch device shortcuts


Shortcut Description
Single tap Move the cursor
Double tap Text selection on the tapped word (opens context menu)
Triple tap Text selection on the tapped row (opens context menu)
Hold Context menu
Touch + drag Text selection until the touch is released (opens context menu)

Compiler IDE

Shortcut Description
Single tap Equivalent to single mouse click
Double tap Equivalent to double mouse click
Hold Equivalent to right click (opens context menu)
Touch + drag Equivalent to mouse dragging