Configurator is live

Fast ESP32 tooling that just works.

Debugging an ESP32 shouldn't mean slow steps and a frozen IDE. Coil is a new JTAG debugger built to be fast and never hang. Its pin configurator is live today, so you can catch strapping, flash and PSRAM conflicts before you build the board.

Open the configurator → See the debugger

8S3 & C6 parts

49ordering codes

0 KBuploaded: runs in your browser

Windows · first macOS · planned Linux · later

Debugger · in development · the reason Coil exists

JTAG debugging that's fast, and doesn't freeze.

Debugging an ESP32 today means waiting on every step. Worse, your IDE freezes, and OpenOCD keeps running in the background, holding the board, so before you can debug again you kill it from a command prompt, restart the IDE, or unplug the board. Coil is a new debugger, every layer written from scratch for the chips' built-in USB-JTAG. We measured today's tools on real ESP32-S3 and ESP32-C6 boards first, then built our own transport to see what the link can really do.

Memory read, ESP32-C6

30× faster

OpenOCD5 KiB/s

probe-rs5–6 KiB/s

Coil141–148 KiB/s

measured · verified byte for byte

Step + read registers

<50 ms

OpenOCD132–233 ms

probe-rs129–167 ms

Coil<50 ms

target · link allows 2–15 ms

Flash a one-byte change

~1 s

OpenOCD23.9 s

esptool12.3 s (full)

Coil~1 s

target · incremental flashing

Never stuck waiting

Every operation on the link has a deadline. If the chip stops answering, Coil tells you and recovers the session instead of freezing your editor, and no stray process is left holding the board.

design goal

Survives resets and sleep

Resets, deep sleep, a panic or a USB reconnect are normal on an ESP32. Coil reattaches on its own, keeping your breakpoints.

design goal

Tells you why

USB pins reused by your firmware, JTAG disabled in eFuse, the chip in download mode, a missing driver: a plain message with the fix, not a log to dig through.

design goal

OpenOCD v0.12.0-esp32-20260424 and probe-rs 0.32.0 over the chips' built-in USB-JTAG on Windows, 20 runs each. Coil's memory read uses the RISC-V debug module's system bus access with 512 reads per USB transfer. Targets are what the measured link allows, not yet a released product.

Pin configurator · available now

The pin planner ESP32 never had.

STM32 developers have CubeMX. ESP32 developers find out about strapping pins, flash pins and PSRAM conflicts when the board doesn't boot. Coil checks your pin plan against the exact part you're using.

Every module, drawn to scale

S3-MINI-1, WROOM-1, WROOM-2, C6-MINI-1, C6-WROOM-1 and the bare QFN chips, from their real footprints, with the variant you actually ordered.

Conflicts as you click

Strapping pins, flash and PSRAM pins, USB-JTAG, ADC2 with Wi-Fi, 1.8 V pins, a signal on two pins: each with a plain explanation and its datasheet source.

board.h that compiles

Pin defines plus your UART, I²C, SPI, PWM and pin settings as ESP-IDF's own constants. Tested against ESP-IDF v6.0.2 with -Werror.

ESP32-S3ESP32-S3-MINI-1ESP32-S3-WROOM-1ESP32-S3-WROOM-2 ESP32-C6ESP32-C6FH4/FH8ESP32-C6-MINI-1ESP32-C6-WROOM-1 more families soon

Where you'll use it · planned

In the editor you already use, or in Coil's own IDE.

The debugger, flasher, monitor and configurator run in one fast background engine. Two front ends will sit on top of it: an extension for VS Code, and a complete IDE for people who want everything in one install.

planned · M5

Coil for VS Code

Keep your editor, settings and extensions. Coil adds ESP32 build, flash, monitor and debugging that start in a second and don't hang.

One-click Build, Flash, Monitor and Debug for ESP-IDF projects
The Coil debugger behind VS Code's own debug view
Fast code navigation with clangd, set up for you
Device panel and the pin configurator inside the editor
Windows first, then macOS (M6)

planned · M8

Coil IDE

A complete ESP32 IDE in one installer, for new projects and new team members. No toolchain hunting, no driver guesswork.

Everything in the VS Code extension, ready out of the box
Toolchains and ESP-IDF versions installed and switched for you
Guided first project, and a friendly mode for Arduino users
Settings view that replaces menuconfig

Coil Pro · planned

Free for everyone. Pro for teams that ship.

The tools that fix everyday ESP32 pain stay free. Coil Pro adds what professional teams need to find hard bugs, test on real hardware and build products. No dates or prices yet: the debugger comes first.

Free, always DebuggerFlashingSerial monitorPin configuratorVS Code extensionclangd setup

Live watch and graphs

Plot variables, buffers and sensor values while the chip keeps running, without halting it. Built on Coil's fast memory reads.

RTOS trace

FreeRTOS tasks, interrupts and context switches on a timeline, on both cores. CPU load per task, stack high-water marks, priority problems.

Hardware-in-the-loop tests

Run tests on real boards from GitHub Actions or Jenkins. Coil flashes, runs, collects results, and saves a core dump when a test fails.

Crash triage

Decode panics and core dumps from devices in the field, grouped by crash, with file and line, firmware version and how often it happens.

Remote debugging

Debug a board plugged into a lab PC or test rack from your own desk, as if it were on your USB port.

Production programming

A flashing station for manufacturing: firmware, eFuses, secure boot and flash-encryption keys, serial numbers, and a log for every device.

Pro also includes priority support and long-term support for chosen ESP-IDF versions. Planned features may change as we learn what teams need.

Roadmap

Small, useful steps.

Each stage ships something you can use on its own.

M0 · DONE

IntelliSense that works

clangd set up correctly for ESP-IDF v5 and v6 projects, Xtensa and RISC-V.

M1 · DONE

Measure, then build

Benchmarks of today's debuggers, and Coil's own USB-JTAG transport.

M2 · NOW

Pin configurator

Pin planning for every S3 and C6 module and chip. Live now.

M3 · NEXT

Debugger

Halt, step and inspect over built-in USB-JTAG, fast and without freezes.

Flash and monitor

Flash only what changed in about a second; serial monitor and debugger side by side; readable panics.

VS Code extension

Coil inside VS Code: one click to build, flash and debug.

M6 · MACOS

Coil on macOS

The debugger, flashing and the VS Code extension on Apple Silicon and Intel Macs. No driver to install.

More chips

ESP32, C3, S2, H2 and others, external probes like ESP-Prog, and Linux.

Coil IDE

The complete ESP32 IDE in one installer.

Plan your next board in five minutes.

No install, no account. Everything runs in your browser and nothing is uploaded.

Open the configurator →