Learn Prompting occupies an unusual and welcome position in a corner of the internet that is absolutely flooded with low-quality prompt engineering content. It started as an open-source guide and grew into something with real academic involvement, including collaboration on prompt engineering research, and that heritage is the main reason I trust it more than the typical ten-dollar Udemy course or the endless threads promising secret prompts. The free guide is the heart of it and it is genuinely good. It walks you from the basics of how to structure a prompt through to more advanced ideas like chain-of-thought, few-shot prompting, and techniques for getting more reliable output, and it does not stop at the fun stuff, it also covers prompt injection, jailbreaking and AI red teaming, which is the kind of thing you actually need to understand if you are building anything real on top of these models.
Because it is community-maintained, it stays reasonably current rather than describing a version of ChatGPT that no longer exists. The honest caveats are worth stating. The site has clearly moved toward a business model, so alongside the free material you will be pointed at paid courses and certification, and while those have value for people who want structured lessons or a credential, plenty of readers will get everything they need from the free guide and never need to pay. There is also a bigger philosophical point, which is that prompt engineering as a discrete skill is a moving target.
As models get better at understanding sloppy instructions, some of the more elaborate techniques matter less than they did a year ago, so I would learn the principles here rather than memorising specific tricks. A certificate that says you are good at prompting is also not something I would lean on by itself in a job search. My recommendation is to treat the free guide as the main event. Read it, apply it to whatever you are actually working on, and you will be ahead of most people who claim prompt engineering on their CV.
Consider the paid track only if you specifically want the structure or the certificate, and go in clear-eyed that the underlying skill will keep shifting as the models do.