The Neighbours

PlatformIO is one answer to "how do I build for boards." These are the others you will meet, and what each trades.

The Arduino IDE

The friendly face of board programming: pick a board, pick a port, press the arrow. For a first blink it cannot be beaten, and its library manager taught the world the shape of the problem. What it trades away is the file: board settings, library versions and options live in the editor's state and your memory, sketches are single-program affairs, and there is no desktop twin, no test runner, no second machine story. Many people start here and arrive at PlatformIO (or the next entry) carrying a sketch — which the Arduino framework setting welcomes unchanged, as this guide's Uno build shows.

The Arduino CLI

Arduino's own command line: arduino-cli compile --fqbn ..., with libraries and boards managed in its own config. It does honestly most of what this guide does for Arduino boards specifically — reproducible-ish builds, scriptability — with a smaller download and a narrower world: Arduino cores only, a thinner library-versioning story, no native test environment of the same shape.

The vendor frameworks: ESP-IDF, STM32Cube, Zephyr

Each chip family also offers its own house toolchain — Espressif's ESP-IDF, ST's Cube, the Linux Foundation's Zephyr RTOS. They go deeper than PlatformIO can: the newest chip features first, the vendor's own debuggers and examples, support contracts. The trade is scope and portability: learn ESP-IDF and you know ESP32, in depth, and nothing else transfers except the C. Notably, PlatformIO can sit on top of several of them — framework = espidf is a real configuration — acting as the fetching-and-organising layer over the vendor's own build, which is perhaps the clearest statement of what PlatformIO itself is.

Plain Make and CMake

The ancestors: a hand-written build file naming the cross-compiler, the flags, the sources. Total control, nothing downloaded behind your back, and every problem in this guide — finding toolchains, pinning libraries, adding a board, testing on the desk — reappearing as your problem, in your file, forever. Right for a team that already has that expertise and a reason; a heavy way to blink an LED.

MicroPython and CircuitPython

A different answer entirely: put a Python interpreter on the board and skip compiling — copy a .py file across, and it runs. For learning, sensors-and-scripting projects, and anything that changes hourly, it is delightful and this shelf's MicroPython guide covers it. The trades are speed, memory (the interpreter lives in the same kilobytes your program wanted), and a ceiling you meet the day the project needs a library that exists only in C — at which point the road leads back here.

Check: the choosing question

Ask of any project: how many boards, how long a life, how many machines must rebuild it? One board, one afternoon, one laptop — the IDE is honestly enough. Anything past that, the project file starts paying rent — and that rent is the subject of this guide.