esp32sim
Open-source ESP32 emulator written in Rust; runs unmodified firmware locally or in a browser, booting the real mask ROM and modeling displays, WiFi, and peripherals with no hardware required.
What it does and how it connects
esp32sim is an ESP32 emulator written in Rust. It runs real ESP32 firmware on the user's computer or in a browser tab, without the hardware. It boots the chip's own mask ROM, the real second-stage bootloader, and the unmodified application, and models the board around the chip: displays, touch, LEDs, buttons, audio, camera and WiFi.
Supported chips stated in the README are ESP32-S3 (mature), ESP32-C3 and ESP32-C6 (draft), classic ESP32 (early), and ESP32-P4 (draft). WiFi uses the unmodified Espressif WiFi library: firmware joins a virtual access point, gets DHCP, DNS and NTP, and can reach the real network, HTTPS included. The S3 has a block cache and a JIT, and runs hello_world about 30 times faster than real time. A WebAssembly build of the same emulator runs in the browser, and comparisons with real chips are published (S3 in JTAG lock-step, C3 and C6 by console diff).
Demos on the demo site include Linux 6.11 on the ESP32-S3 with a login shell, the Atech kit's Pocket Synth, an LVGL touch panel, pocket-tank, an 802.15.4 energy scanner with two Contiki-NG motes on the ESP32-C6, and MicroPython on a classic ESP32 T-Display. Prebuilt binaries for macOS and Linux ship on the releases page, and the mask ROMs are fetched by a script since they are not in the repo.
What engineers report
Two defects found running unmodified ESP-IDF v5.3.3 Rust firmware (M5StickC Plus, M5Paper) on the classic ESP32 model, at ba58b16c. Both are still in the source at 04f07602.
2026-10-31Read the original
Alternatives
Compare side by side- esp-device-broker-mcp
A single-owner MCP broker that runs jobs on real ESP32 boards, rather than an emulator that runs firmware with no hardware.
- silica-eda
An MCP server that gives coding agents structured access to an RTL-to-bitstream toolchain and programs an FPGA board, rather than an ESP32 emulator.
Sources
Not verified
- Pricing: none stated on the repo; the emulator is free and open source.
- No matching Error Index entry verified for this emulator, so related errors are empty.
Last verified November 6, 2026. Listings are informational. The evidence score measures public, verifiable evidence and is not an endorsement or a compatibility claim.