esptool

June 5, 2026 ยท View on GitHub

A Python-based, open-source, platform-independent serial utility for flashing, provisioning, and interacting with Espressif SoCs.

Test esptool Build esptool pre-commit.ci status

Documentation

Visit the documentation or run esptool -h.

Flasher Stub

esptool uploads a small flasher stub program to the chip to improve flashing performance and work around ROM bootloader limitations. The stub is developed in the esp-flasher-stub repository. Prebuilt binaries are bundled with esptool releases.

Contribute

If you're interested in contributing to esptool, please check the contributions guide.

About

esptool was initially created by Fredrik Ahlberg (@themadinventor), and later maintained by Angus Gratton (@projectgus). It is now supported by Espressif Systems. It has also received improvements from many members of the community.

License

This document and the attached source code are released as Free Software under GNU General Public License Version 2 or later. See the accompanying LICENSE file for a copy.