4 jobs in 4 years on IT would be seen as a yellow flag for any HR person sourcing candidates for a position. Then it would be really up to the hiring manager. But definitely, as you have noticed, it is something it will be spotted.
It's natural to question this when hiring. Soon you will progress on your career and you will have to hire. Then, if you get a resume from a young person that has been 4 jobs in 4 years, you will be asking yourself the same question, is he going to leave on a year?
There are many valid reasons to leave jobs frequently. Even boredom is a valid reason. Without knowing your actual reasons, personally, if I find myself changing often, I would consider whether I should be contracting instead of going permanent.
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