What Breadboard is

Breadboard behaves like a bench, not a diagram tool. Parts place freely on an open canvas and wire pin-to-pin (breadboards are just another part when you want one). Underneath, a from-scratch SPICE-style solver computes every node voltage continuously, so meters read real numbers, LEDs dim realistically with series resistance, and a part wired past its ratings genuinely burns out.

What's real here

• The analog engine: modified nodal analysis with Newton–Raphson, the same math family as SPICE. Capacitors charge, inductors kick, op-amps clip, the 555 oscillates because its comparators actually compare.
• The microcontrollers: an ATmega328P (Arduino Uno), a Raspberry Pi Pico (RP2040), and four ESP32s (the classic dual-core LX6, the C3, the dual-core S3, and the C6) are emulated at the instruction level and boot unmodified vendor firmware: MicroPython to a live REPL, ESP-IDF apps, compiled Arduino sketches.
• The radio: the ESP32's Wi-Fi comes up through the genuine Espressif stack against a virtual ether: scan finds networks, WPA2 does its real 4-way handshake, two boards on one bench talk over actual 802.11 frames.
• The failure modes: power ratings, current limits, and fuses are enforced. Mistakes look like mistakes: smoke, scorch marks, and a diagnostic telling you why.

Where to start

1. 1Open Examples in the header: every card shows a live preview of the circuit it loads, and scripted examples run themselves.
2. 2Take a guided tutorial (Help → Guided tutorials): the app watches your circuit and each step completes when you've actually done it.
3. 3Or just build: read Getting started next and light an LED in two minutes.