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MicroPython libraries


Important summary of this section

  • MicroPython provides built-in modules that mirror the functionality of the Python standard library (e.g. os, time), as well as MicroPython-specific modules (e.g. bluetooth, machine).

  • Most Python standard library modules implement a subset of the functionality of the equivalent Python module, and in a few cases provide some MicroPython-specific extensions (e.g. array, os)

  • Due to resource constraints or other limitations, some ports or firmware versions may not include all the functionality documented here.

  • To allow for extensibility, some built-in modules can be extended from Python code loaded onto the device filesystem.

This chapter describes modules (function and class libraries) which are built into MicroPython. This documentation in general aspires to describe all modules and functions/classes which are implemented in the MicroPython project. However, MicroPython is highly configurable, and each port to a particular board/embedded system may include only a subset of the available MicroPython libraries.

With that in mind, please be warned that some functions/classes in a module (or even the entire module) described in this documentation may be unavailable in a particular build of MicroPython on a particular system. The best place to find general information of the availability/non-availability of a particular feature is the “General Information” section which contains information pertaining to a specific MicroPython port.

On some ports you are able to discover the available, built-in libraries that can be imported by entering the following at the REPL:


Beyond the built-in libraries described in this documentation, many more modules from the Python standard library, as well as further MicroPython extensions to it, can be found in micropython-lib.

Python standard libraries and micro-libraries

The following standard Python libraries have been “micro-ified” to fit in with the philosophy of MicroPython. They provide the core functionality of that module and are intended to be a drop-in replacement for the standard Python library.

MicroPython-specific libraries

Functionality specific to the MicroPython implementation is available in the following libraries.

The following libraries provide drivers for hardware components.

Port-specific libraries

In some cases the following port/board-specific libraries have functions or classes similar to those in the machine library. Where this occurs, the entry in the port specific library exposes hardware functionality unique to that platform.

To write portable code use functions and classes from the machine module. To access platform-specific hardware use the appropriate library, e.g. pyb in the case of the Pyboard.

Libraries specific to the pyboard

The following libraries are specific to the pyboard.

Libraries specific to the WiPy

The following libraries and classes are specific to the WiPy.

Libraries specific to the ESP8266 and ESP32

The following libraries are specific to the ESP8266 and ESP32.

Libraries specific to the RP2040

The following libraries are specific to the RP2040, as used in the Raspberry Pi Pico.

Libraries specific to Zephyr

The following libraries are specific to the Zephyr port.

Extending built-in libraries from Python

A subset of the built-in modules are able to be extended by Python code by providing a module of the same name in the filesystem. This extensibility applies to the following Python standard library modules which are built-in to the firmware: array, binascii, collections, errno, gzip, hashlib, heapq, io, json, os, platform, random, re, select, socket, ssl, struct, time zlib, as well as the MicroPython-specific machine module. All other built-in modules cannot be extended from the filesystem.

This allows the user to provide an extended implementation of a built-in library (perhaps to provide additional CPython compatibility or missing functionality). This is used extensively in micropython-lib, see Package management for more information. The filesystem module will typically do a wildcard import of the built-in module in order to inherit all the globals (classes, functions and variables) from the built-in.

In MicroPython v1.21.0 and higher, to prevent the filesystem module from importing itself, it can force an import of the built-in module it by temporarily clearing sys.path during the import. For example, to extend the time module from Python, a file named on the filesystem would do the following:

_path = sys.path
sys.path = ()
  from time import *
  sys.path = _path
  del _path

def extra_method():

The result is that contains all the globals of the built-in time module, but adds extra_method.

In earlier versions of MicroPython, you can force an import of a built-in module by appending a u to the start of its name. For example, import utime instead of import time. For example, on the filesystem could look like:

from utime import *

def extra_method():

This way is still supported, but the sys.path method described above is now preferred as the u-prefix will be removed from the names of built-in modules in a future version of MicroPython.

Other than when it specifically needs to force the use of the built-in module, code should always use import module rather than import umodule.