Browser-Based ESP32 & ESP8266 Flash Tool
The serial monitor uses a separate port from the flasher. You cannot use both simultaneously on the same COM port.
If the output looks garbled, the baud rate probably doesn't match your firmware's Serial.begin() value.
Boot messages appear immediately on port open. If you miss them, press the EN / RST button on your board.
No drivers, no IDE, no installation needed. Plug in your board and flash firmware directly from this browser page in under two minutes.
| Chip Family | Bootloader | Partition Table | App |
|---|---|---|---|
| ESP32 (classic) | 0x1000 | 0x8000 | 0x10000 |
| ESP32-S2 / S3 | 0x0 | 0x8000 | 0x10000 |
| ESP32-C3 / C6 / H2 | 0x0 | 0x8000 | 0x10000 |
| ESP8266 | 0x0 | N/A | 0x0 |
For a single merged / factory .bin, always use address 0x0 regardless of chip.
This tool uses the Web Serial API — a secure browser API that allows web pages to communicate with USB serial devices without any drivers or installed software. It is supported in Google Chrome and Microsoft Edge version 89 and above on Windows, macOS, and Linux desktops. It is not available in Firefox, Safari, or any mobile browser.
The Web Serial API allows supported browsers to communicate directly with your computer's USB and serial ports. This happens entirely locally on your machine.
When you click "Connect Device", the browser asks you to grant permission to a specific port. We do not have access to any other devices on your computer.
Privacy Promise: Your firmware files are read locally by your browser and sent directly to the ESP chip. No firmware files, code, or analytics are ever uploaded to our servers.
A professional browser-based firmware flashing tool for the ESP32 and ESP8266 family of microcontrollers.
ESP Flasher App lets you flash firmware onto any ESP32 or ESP8266 device directly from your web browser — without installing drivers, an IDE, or any software.
It uses the Web Serial API and Espressif's official esptool-js library to implement the full ROM bootloader protocol. All processing happens locally in your browser. No files are uploaded to any server.
Your firmware files never leave your device. The flasher communicates directly between your browser and your ESP board over the local USB serial connection.
No analytics, no trackers, no ads. We do not collect or store any user data through this tool.
ESP Flasher App is a professional browser-based firmware flashing tool for the ESP32 and ESP8266 family of microcontrollers. It lets you flash firmware onto any ESP device directly from your web browser — without installing drivers, an IDE, or any software.
This tool was built to make firmware deployment simpler for both beginners and professionals — no command line, no driver hunting, no IDE bloat. Using the Web Serial API and Espressif's official esptool-js library, all processing happens locally in your browser.