Install

Flash Frothy from the browser, check the board, and start writing.

You do not need to clone Frothy or install a compiler to get started. The browser flasher installs ready-made firmware, and the browser editor talks to the board directly over USB.

What You Need

a supported board and a USB data cable
desktop Chrome, Edge, or Opera
macOS, Linux, or Windows

1. Flash The Board

Open the Frothy browser flasher , choose your board, and select Flash Frothy. Keep the page open until the progress bar reaches the end and the board resets.

The flasher uses Web Serial. Your browser will ask which serial device it may use; choose the board you plugged in.

For an RP2040 board, the button is Download Frothy UF2. RP2040 Boards shows the two steps after the download.

If No Port Appears

If the browser lists no port, or not your board:

Use a USB cable that carries data. Some cables carry only power.
The ESP32 DevKit V1 and the NodeMCU ESP-32S have a USB chip (CP210x or CH340). On some computers, that chip needs a driver from its maker.
Close other tabs and programs that use the serial port, such as a serial monitor.

If the flasher cannot connect to an ESP32 board, start the board in download mode. Hold the BOOT button, press and release the reset button, and then release BOOT. Then select Flash Frothy again.

2. Check Frothy

Choose Check Frothy on the flasher page. This sends a small status request and confirms that the board is reachable and running Frothy.

If the check cannot reach the board, close other applications using its serial port, press the board’s EN button (or unplug and reconnect it), and try again.

3. Start Writing

Continue to the browser editor , choose Connect, and select the same board. Put the cursor on a line and choose Run Line, or click the play marker in the gutter next to the line. A line inside a block runs on its own. The line that opens the block and the line that closes it run the whole block. Run File runs the open file from the top, splicing in any include directives; running main.fr starts the program fresh.

Edits save locally in the browser. Use the file navigator’s download button when you want a normal copy of the project.

VS Code And The CLI

Install the Frothy extension from the VS Code Marketplace (publisher: NikolaiKozak) when you want a local project workflow. The extension uses the installed frothy CLI for serial sessions; the browser tools do not.

Homebrew is the packaged CLI path. It installs the CLI, esptool, and the official release firmware, so frothy flash BOARD does not require a source checkout or ESP-IDF:

brew install nikokozak/frothy/frothy
frothy doctor

frothy doctor confirms the install and looks for a connected board. To build the CLI from source instead, follow the developer setup .