I’ve just passed my GCP Professional architect exam and I thought it would be a good idea to share my experience as I did with the other cloud providers (link here).
First, the exam consists of 50 questions that need to be answered in 2 hours. You can’t have any notes with you. Out of the 50 questions, around 10 are about 4 business cases that you can read beforehand (you can find them here). Be aware that on May 1st, 2021 the cases changed so make sure that you have the latest version. The 50 questions are test-type questions and may have 1 or several correct answers. In the exam, they won't only test you on your GCP knowledge, but they will also test your general architecting experience AND your ability to choose the best possible answer among the correct answers. So the right way to face them is never “option B is the correct answer”, it’s usually “between ABCDE, I know that A and D are wrong and among B C and E I believe that B is the easiest to implement and the most cost-effective one, therefore B is the correct answer”. Another tip: if you don't know the answer to a question in 2 minutes, flag it and move on. Don't get stuck.
Second, one of the challenges of the exam itself is the lack of learning material (at least for the newest version). There is the famous book Google Professional Cloud Architect Study guide from Dan Sullivan (+300 pages) which will help you with the understanding of the core technology in GCP. At the end of each chapter of the book, there are test questions. It might be interesting to take a look but they are far from the level of the exam (they are too easy). Then, there are some summaries that can be helpful to you. I would recommend the Google Cloud Professional Cloud architect by Ammett (link HERE). They are a good overview of the different parts of the technology (don't forget to open the links included in the document itself). On top of these tools, there are the practice environments. I recommend you to use them as much as possible as they are the best tool that you have (even if they incur an additional cost). If your company is a GCP partner, you might have access to internal GCP courses. They are well done and easy to follow. If not, I would simply advise you to create an account and practice practice practice. The best tool to practice is called Qwiklabs. Last, there are Udemy courses. In my opinion, they are far from the level of the exam and too superficial. I wouldn't advise them.
Last but not least, and without trying to discourage anyone, this exam is hard. It's not only hard to study due to the lack of resources aligned with the difficulty of the exam, but also because of the questions themselves. With only good memory you won't pass the exam, you will need a critical thinking spirit and architecting experience. I don’t recommend it as a first step into GCP certification path. If you don’t have any GCP certification experience I would advise you to go first to the fundamentals exam or to the associate cloud engineer one.
As a summary, my advice would be: read and understand the Google Professional architect book, read every morning the summary from Ammett and the 4 business cases, practice with the questions from examtopics.com (without checking the business case questions as they are not updated), try all the Qwiklabs that you can (that's where you really learn) and then go to the exam.
Good luck and let me know if you pass!
PD: Link to my LinkedIn post HERE